Refer to groups by UUID

- Also lays the foundations for adding entries to multiple groups and changing group names

Co-authored-by: Alexander Bakker <ab@alexbakker.me>

app/src/main/java/com/beemdevelopment/aegis/Preferences.java

@@ -20,9 +20,11 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Set;
 import java.util.UUID;
 
 public class Preferences {
@@ -478,26 +480,26 @@ public class Preferences {
         return _prefs.getBoolean("pref_minimize_on_copy", false);
     }
 
-    public void setGroupFilter(List<String> groupFilter) {
+    public void setGroupFilter(Set<UUID> groupFilter) {
         JSONArray json = new JSONArray(groupFilter);
-        _prefs.edit().putString("pref_group_filter", json.toString()).apply();
+        _prefs.edit().putString("pref_group_filter_uuids", json.toString()).apply();
     }
 
-    public List<String> getGroupFilter() {
+    public Set<UUID> getGroupFilter() {
-        String raw = _prefs.getString("pref_group_filter", null);
+        String raw = _prefs.getString("pref_group_filter_uuids", null);
         if (raw == null || raw.isEmpty()) {
-            return Collections.emptyList();
+            return Collections.emptySet();
         }
 
         try {
             JSONArray json = new JSONArray(raw);
-            List<String> filter = new ArrayList<>();
+            Set<UUID> filter = new HashSet<>();
             for (int i = 0; i < json.length(); i++) {
-                filter.add(json.isNull(i) ? null : json.optString(i));
+                filter.add(json.isNull(i) ? null : UUID.fromString(json.getString(i)));
             }
             return filter;
         } catch (JSONException e) {
-            return Collections.emptyList();
+            return Collections.emptySet();
         }
     }
 

app/src/main/java/com/beemdevelopment/aegis/importers/AegisImporter.java

@@ -16,6 +16,7 @@ import com.beemdevelopment.aegis.vault.VaultEntryException;
 import com.beemdevelopment.aegis.vault.VaultFile;
 import com.beemdevelopment.aegis.vault.VaultFileCredentials;
 import com.beemdevelopment.aegis.vault.VaultFileException;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 import com.beemdevelopment.aegis.vault.slots.PasswordSlot;
 import com.beemdevelopment.aegis.vault.slots.SlotList;
 import com.topjohnwu.superuser.io.SuFile;
@@ -27,6 +28,7 @@ import org.json.JSONObject;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
+import java.util.UUID;
 
 public class AegisImporter extends DatabaseImporter {
 
@@ -132,11 +134,31 @@ public class AegisImporter extends DatabaseImporter {
             Result result = new Result();
 
             try {
-                JSONArray array = _obj.getJSONArray("entries");
+                if (_obj.has("groups")) {
-                for (int i = 0; i < array.length(); i++) {
+                    JSONArray groupArray = _obj.getJSONArray("groups");
-                    JSONObject entryObj = array.getJSONObject(i);
+                    for (int i = 0; i < groupArray.length(); i++) {
+                        JSONObject groupObj = groupArray.getJSONObject(i);
+                        try {
+                            VaultGroup group = convertGroup(groupObj);
+                            if (!result.getGroups().has(group)) {
+                                result.addGroup(group);
+                            }
+                        } catch (DatabaseImporterEntryException e) {
+                            result.addError(e);
+                        }
+                    }
+                }
+
+                JSONArray entryArray = _obj.getJSONArray("entries");
+                for (int i = 0; i < entryArray.length(); i++) {
+                    JSONObject entryObj = entryArray.getJSONObject(i);
                     try {
                         VaultEntry entry = convertEntry(entryObj);
+                        for (UUID groupUuid : entry.getGroups()) {
+                            if (!result.getGroups().has(groupUuid)) {
+                                entry.getGroups().remove(groupUuid);
+                            }
+                        }
                         result.addEntry(entry);
                     } catch (DatabaseImporterEntryException e) {
                         result.addError(e);
@@ -156,5 +178,13 @@ public class AegisImporter extends DatabaseImporter {
                 throw new DatabaseImporterEntryException(e, obj.toString());
             }
         }
+
+        private static VaultGroup convertGroup(JSONObject obj) throws DatabaseImporterEntryException {
+            try {
+                return VaultGroup.fromJson(obj);
+            } catch (VaultEntryException e) {
+                throw new DatabaseImporterEntryException(e, obj.toString());
+            }
+        }
     }
 }

app/src/main/java/com/beemdevelopment/aegis/importers/DatabaseImporter.java

@@ -8,6 +8,7 @@ import androidx.annotation.StringRes;
 import com.beemdevelopment.aegis.R;
 import com.beemdevelopment.aegis.util.UUIDMap;
 import com.beemdevelopment.aegis.vault.VaultEntry;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 import com.topjohnwu.superuser.Shell;
 import com.topjohnwu.superuser.io.SuFile;
 import com.topjohnwu.superuser.io.SuFileInputStream;
@@ -168,12 +169,17 @@ public abstract class DatabaseImporter {
 
     public static class Result {
         private UUIDMap<VaultEntry> _entries = new UUIDMap<>();
+        private UUIDMap<VaultGroup> _groups = new UUIDMap<>();
         private List<DatabaseImporterEntryException> _errors = new ArrayList<>();
 
         public void addEntry(VaultEntry entry) {
             _entries.add(entry);
         }
 
+        public void addGroup(VaultGroup group) {
+            _groups.add(group);
+        }
+
         public void addError(DatabaseImporterEntryException error) {
             _errors.add(error);
         }
@@ -182,6 +188,10 @@ public abstract class DatabaseImporter {
             return _entries;
         }
 
+        public UUIDMap<VaultGroup> getGroups() {
+            return _groups;
+        }
+
         public List<DatabaseImporterEntryException> getErrors() {
             return _errors;
         }

app/src/main/java/com/beemdevelopment/aegis/ui/EditEntryActivity.java

@@ -1,7 +1,7 @@
 package com.beemdevelopment.aegis.ui;
 
+import android.content.DialogInterface;
 import android.content.Intent;
-import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
@@ -15,7 +15,6 @@ import android.view.ViewGroup;
 import android.view.animation.AccelerateInterpolator;
 import android.view.animation.AlphaAnimation;
 import android.view.animation.Animation;
-import android.widget.AdapterView;
 import android.widget.AutoCompleteTextView;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
@@ -54,11 +53,13 @@ import com.beemdevelopment.aegis.otp.YandexInfo;
 import com.beemdevelopment.aegis.ui.dialogs.Dialogs;
 import com.beemdevelopment.aegis.ui.dialogs.IconPickerDialog;
 import com.beemdevelopment.aegis.ui.glide.IconLoader;
+import com.beemdevelopment.aegis.ui.models.VaultGroupModel;
 import com.beemdevelopment.aegis.ui.tasks.ImportFileTask;
 import com.beemdevelopment.aegis.ui.views.IconAdapter;
 import com.beemdevelopment.aegis.util.Cloner;
 import com.beemdevelopment.aegis.util.IOUtils;
 import com.beemdevelopment.aegis.vault.VaultEntry;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 import com.beemdevelopment.aegis.vault.VaultRepository;
 import com.bumptech.glide.Glide;
 import com.bumptech.glide.load.engine.DiskCacheStrategy;
@@ -73,11 +74,14 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
-import java.util.TreeSet;
+import java.util.Objects;
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Collectors;
@@ -90,7 +94,7 @@ public class EditEntryActivity extends AegisActivity {
     private boolean _isNew = false;
     private boolean _isManual = false;
     private VaultEntry _origEntry;
-    private TreeSet<String> _groups;
+    private Collection<VaultGroup> _groups;
     private boolean _hasCustomIcon = false;
     // keep track of icon changes separately as the generated jpeg's are not deterministic
     private boolean _hasChangedIcon = false;
@@ -114,7 +118,7 @@ public class EditEntryActivity extends AegisActivity {
     private AutoCompleteTextView _dropdownAlgo;
     private TextInputLayout _dropdownAlgoLayout;
     private AutoCompleteTextView _dropdownGroup;
-    private List<String> _dropdownGroupList = new ArrayList<>();
+    private List<VaultGroupModel> _dropdownGroupList = new ArrayList<>();
 
     private KropView _kropView;
 
@@ -262,8 +266,13 @@ public class EditEntryActivity extends AegisActivity {
         updateAdvancedFieldStatus(_origEntry.getInfo().getTypeId());
         updatePinFieldVisibility(_origEntry.getInfo().getTypeId());
 
-        String group = _origEntry.getGroup();
+        Set<UUID> groups = _origEntry.getGroups();
-        setGroup(group);
+        if (groups.isEmpty()) {
+            setGroup(new VaultGroupModel(getString(R.string.no_group)));
+        } else {
+            VaultGroup group = _vaultManager.getVault().getGroupByUUID(groups.iterator().next());
+            setGroup(new VaultGroupModel(group));
+        }
 
         // Update the icon if the issuer or name has changed
         _textIssuer.addTextChangedListener(_nameChangeListener);
@@ -327,24 +336,31 @@ public class EditEntryActivity extends AegisActivity {
             startIconSelection();
         });
 
-        _dropdownGroup.setOnItemClickListener(new AdapterView.OnItemClickListener() {
+        _dropdownGroup.setOnItemClickListener((parent, view, position, id) -> {
-            private int prevPosition = _dropdownGroupList.indexOf(_dropdownGroup.getText().toString());
+            VaultGroupModel selectedGroup = _dropdownGroupList.get(position);
-
+            if (selectedGroup.isPlaceholder() && Objects.equals(selectedGroup.getName(), getString(R.string.new_group))) {
-            @Override
+                Dialogs.TextInputListener onAddGroup = text -> {
-            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+                    String groupName = new String(text).trim();
-                if (position == _dropdownGroupList.size() - 1) {
+                    if (!groupName.isEmpty()) {
-                    Dialogs.showTextInputDialog(EditEntryActivity.this, R.string.set_group, R.string.group_name_hint, text -> {
+                        VaultGroup group = _vaultManager.getVault().findGroupByName(groupName);
-                        String groupName = new String(text);
+                        if (group == null) {
-                        if (!groupName.isEmpty()) {
+                            group = new VaultGroup(groupName);
-                            _groups.add(groupName);
+                            _vaultManager.getVault().addGroup(group);
-                            updateGroupDropdownList();
-                            _dropdownGroup.setText(groupName, false);
                         }
-                    });
+
-                    _dropdownGroup.setText(_dropdownGroupList.get(prevPosition), false);
+                        updateGroupDropdownList();
-                } else {
+                        setGroup(new VaultGroupModel(group));
-                    prevPosition = position;
+                    }
-                }
+                };
+
+                DialogInterface.OnCancelListener onCancel = dialogInterface -> {
+                    VaultGroupModel previous = (VaultGroupModel) _dropdownGroup.getTag();
+                    _dropdownGroup.setText(previous.getName(), false);
+                };
+
+                Dialogs.showTextInputDialog(EditEntryActivity.this, R.string.set_group, R.string.group_name_hint, onAddGroup, onCancel);
+            } else {
+                setGroup(_dropdownGroupList.get(position));
             }
         });
 
@@ -365,13 +381,9 @@ public class EditEntryActivity extends AegisActivity {
         _textPin.setHint(otpType.equals(MotpInfo.ID) ? R.string.motp_pin : R.string.yandex_pin);
     }
 
-    private void setGroup(String groupName) {
+    private void setGroup(VaultGroupModel group) {
-        int pos = 0;
+        _dropdownGroup.setText(group.getName(), false);
-        if (groupName != null) {
+        _dropdownGroup.setTag(group);
-            pos = _groups.contains(groupName) ? _groups.headSet(groupName).size() + 1 : 0;
-        }
-
-        _dropdownGroup.setText(_dropdownGroupList.get(pos), false);
     }
 
     private void openAdvancedSettings() {
@@ -395,11 +407,10 @@ public class EditEntryActivity extends AegisActivity {
     }
 
     private void updateGroupDropdownList() {
-        Resources res = getResources();
         _dropdownGroupList.clear();
-        _dropdownGroupList.add(res.getString(R.string.no_group));
+        _dropdownGroupList.add(new VaultGroupModel(getString(R.string.new_group)));
-        _dropdownGroupList.addAll(_groups);
+        _dropdownGroupList.addAll(_groups.stream().map(VaultGroupModel::new).collect(Collectors.toList()));
-        _dropdownGroupList.add(res.getString(R.string.new_group));
+        _dropdownGroupList.add(new VaultGroupModel(getString(R.string.no_group)));
     }
 
     private boolean hasUnsavedChanges(VaultEntry newEntry) {
@@ -726,12 +737,13 @@ public class EditEntryActivity extends AegisActivity {
         entry.setName(_textName.getText().toString());
         entry.setNote(_textNote.getText().toString());
 
-        int groupPos = _dropdownGroupList.indexOf(_dropdownGroup.getText().toString());
+        VaultGroupModel group = (VaultGroupModel) _dropdownGroup.getTag();
-        if (groupPos != 0) {
+        if (group.isPlaceholder()) {
-            String group = _dropdownGroupList.get(groupPos);
+            entry.setGroups(new HashSet<>());
-            entry.setGroup(group);
         } else {
-            entry.setGroup(null);
+            Set<UUID> groups = new HashSet<>();
+            groups.add(group.getUUID());
+            entry.setGroups(groups);
         }
 
         if (_hasChangedIcon) {

app/src/main/java/com/beemdevelopment/aegis/ui/GroupManagerActivity.java

@@ -14,16 +14,17 @@ import androidx.recyclerview.widget.RecyclerView;
 import com.beemdevelopment.aegis.R;
 import com.beemdevelopment.aegis.ui.dialogs.Dialogs;
 import com.beemdevelopment.aegis.ui.views.GroupAdapter;
-import com.beemdevelopment.aegis.vault.VaultEntry;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
 
 public class GroupManagerActivity extends AegisActivity implements GroupAdapter.Listener {
     private GroupAdapter _adapter;
-    private HashSet<String> _removedGroups;
+    private HashSet<UUID> _removedGroups;
     private RecyclerView _groupsView;
     private View _emptyStateView;
     private BackPressHandler _backPressHandler;
@@ -43,11 +44,14 @@ public class GroupManagerActivity extends AegisActivity implements GroupAdapter.
         _backPressHandler = new BackPressHandler();
         getOnBackPressedDispatcher().addCallback(this, _backPressHandler);
 
+        _removedGroups = new HashSet<>();
         if (savedInstanceState != null) {
             List<String> groups = savedInstanceState.getStringArrayList("removedGroups");
-            _removedGroups = new HashSet<>(Objects.requireNonNull(groups));
+            if (groups != null) {
-        } else {
+                for (String uuid : groups) {
-            _removedGroups = new HashSet<>();
+                    _removedGroups.add(UUID.fromString(uuid));
+                }
+            }
         }
 
         _adapter = new GroupAdapter(this);
@@ -57,8 +61,10 @@ public class GroupManagerActivity extends AegisActivity implements GroupAdapter.
         _groupsView.setAdapter(_adapter);
         _groupsView.setNestedScrollingEnabled(false);
 
-        for (String group : _vaultManager.getVault().getGroups()) {
+        for (VaultGroup group : _vaultManager.getVault().getGroups()) {
-            _adapter.addGroup(group);
+            if (!_removedGroups.contains(group.getUUID())) {
+                _adapter.addGroup(group);
+            }
         }
 
         _emptyStateView = findViewById(R.id.vEmptyList);
@@ -68,16 +74,21 @@ public class GroupManagerActivity extends AegisActivity implements GroupAdapter.
     @Override
     protected void onSaveInstanceState(@NonNull Bundle outState) {
         super.onSaveInstanceState(outState);
-        outState.putStringArrayList("removedGroups", new ArrayList<>(_removedGroups));
+        ArrayList<String> removed = new ArrayList<>();
+        for (UUID uuid : _removedGroups) {
+            removed.add(uuid.toString());
+        }
+
+        outState.putStringArrayList("removedGroups", removed);
     }
 
     @Override
-    public void onRemoveGroup(String group) {
+    public void onRemoveGroup(VaultGroup group) {
         Dialogs.showSecureDialog(new AlertDialog.Builder(this)
                 .setTitle(R.string.remove_group)
                 .setMessage(R.string.remove_group_description)
                 .setPositiveButton(android.R.string.yes, (dialog, whichButton) -> {
-                    _removedGroups.add(group);
+                    _removedGroups.add(group.getUUID());
                     _adapter.removeGroup(group);
                     _backPressHandler.setEnabled(true);
                     updateEmptyState();
@@ -86,12 +97,29 @@ public class GroupManagerActivity extends AegisActivity implements GroupAdapter.
                 .create());
     }
 
+    public void onRemoveUnusedGroups() {
+        Dialogs.showSecureDialog(new AlertDialog.Builder(this)
+                .setTitle(R.string.remove_unused_groups)
+                .setMessage(R.string.remove_unused_groups_description)
+                .setPositiveButton(android.R.string.yes, (dialog, whichButton) -> {
+                    Set<VaultGroup> unusedGroups = new HashSet<>(_vaultManager.getVault().getGroups());
+                    unusedGroups.removeAll(_vaultManager.getVault().getUsedGroups());
+
+                    for (VaultGroup group : unusedGroups) {
+                        _removedGroups.add(group.getUUID());
+                        _adapter.removeGroup(group);
+                    }
+                    _backPressHandler.setEnabled(true);
+                    updateEmptyState();
+                })
+                .setNegativeButton(android.R.string.no, null)
+                .create());
+    }
+
     private void saveAndFinish() {
         if (!_removedGroups.isEmpty()) {
-            for (VaultEntry entry : _vaultManager.getVault().getEntries()) {
+            for (UUID uuid : _removedGroups) {
-                if (_removedGroups.contains(entry.getGroup())) {
+                _vaultManager.getVault().removeGroup(uuid);
-                    entry.setGroup(null);
-                }
             }
 
             saveAndBackupVault();
@@ -126,6 +154,9 @@ public class GroupManagerActivity extends AegisActivity implements GroupAdapter.
             case R.id.action_save:
                 saveAndFinish();
                 break;
+            case R.id.action_delete_unused_groups:
+                onRemoveUnusedGroups();
+                break;
             default:
                 return super.onOptionsItemSelected(item);
         }

app/src/main/java/com/beemdevelopment/aegis/ui/ImportEntriesActivity.java

@@ -25,6 +25,7 @@ import com.beemdevelopment.aegis.ui.tasks.RootShellTask;
 import com.beemdevelopment.aegis.ui.views.ImportEntriesAdapter;
 import com.beemdevelopment.aegis.util.UUIDMap;
 import com.beemdevelopment.aegis.vault.VaultEntry;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 import com.beemdevelopment.aegis.vault.VaultRepository;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.google.android.material.snackbar.Snackbar;
@@ -37,6 +38,7 @@ import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Set;
 import java.util.UUID;
 
 public class ImportEntriesActivity extends AegisActivity {
@@ -45,6 +47,8 @@ public class ImportEntriesActivity extends AegisActivity {
     private ImportEntriesAdapter _adapter;
     private FabScrollHelper _fabScrollHelper;
 
+    private UUIDMap<VaultGroup> _importedGroups;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -205,6 +209,8 @@ public class ImportEntriesActivity extends AegisActivity {
             importEntries.add(importEntry);
         }
 
+        _importedGroups = result.getGroups();
+
         List<DatabaseImporterEntryException> errors = result.getErrors();
         if (errors.size() > 0) {
             String message = getResources().getQuantityString(R.plurals.import_error_dialog, errors.size(), errors.size());
@@ -225,10 +231,43 @@ public class ImportEntriesActivity extends AegisActivity {
     private void saveAndFinish(boolean wipeEntries) {
         VaultRepository vault = _vaultManager.getVault();
         if (wipeEntries) {
-            vault.wipeEntries();
+            vault.wipeContents();
         }
 
+        // Given the list of selected entries, collect the UUID's of all groups
+        // that we're actually going to import
         List<ImportEntry> selectedEntries = _adapter.getCheckedEntries();
+        List<UUID> selectedGroupUuids = new ArrayList<>();
+        for (ImportEntry entry : selectedEntries) {
+            selectedGroupUuids.addAll(entry.getEntry().getGroups());
+        }
+
+        // Add all of the new groups to the vault. If a group with the same name already
+        // exists in the vault, rewrite all entries in that group to reference the existing group.
+        for (VaultGroup importedGroup : _importedGroups) {
+            if (!selectedGroupUuids.contains(importedGroup.getUUID())) {
+                continue;
+            }
+
+            VaultGroup existingGroup = vault.findGroupByUUID(importedGroup.getUUID());
+            if (existingGroup != null) {
+                continue;
+            }
+
+            existingGroup = vault.findGroupByName(importedGroup.getName());
+            if (existingGroup == null) {
+                vault.addGroup(importedGroup);
+            } else {
+                for (ImportEntry entry : selectedEntries) {
+                    Set<UUID> entryGroups = entry.getEntry().getGroups();
+                    if (entryGroups.contains(importedGroup.getUUID())) {
+                        entryGroups.remove(importedGroup.getUUID());
+                        entryGroups.add(existingGroup.getUUID());
+                    }
+                }
+            }
+        }
+
         for (ImportEntry selectedEntry : selectedEntries) {
             VaultEntry entry = selectedEntry.getEntry();
 

app/src/main/java/com/beemdevelopment/aegis/ui/MainActivity.java

@@ -63,7 +63,7 @@ import java.util.Date;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.TreeSet;
+import java.util.Set;
 import java.util.UUID;
 import java.util.stream.Collectors;
 
@@ -632,7 +632,7 @@ public class MainActivity extends AegisActivity implements EntryListView.Listene
             startAuthActivity(false);
         } else if (_loaded) {
             // update the list of groups in the entry list view so that the chip gets updated
-            _entryListView.setGroups(_vaultManager.getVault().getGroups());
+            _entryListView.setGroups(_vaultManager.getVault().getUsedGroups());
 
             // update the usage counts in case they are edited outside of the EntryListView
             _entryListView.setUsageCounts(_prefs.getUsageCounts());
@@ -670,7 +670,7 @@ public class MainActivity extends AegisActivity implements EntryListView.Listene
 
         updateLockIcon();
         if (_loaded) {
-            _entryListView.setGroups(_vaultManager.getVault().getGroups());
+            _entryListView.setGroups(_vaultManager.getVault().getUsedGroups());
             updateSortCategoryMenu();
         }
 
@@ -980,7 +980,7 @@ public class MainActivity extends AegisActivity implements EntryListView.Listene
     public void onListChange() { _fabScrollHelper.setVisible(true); }
 
     @Override
-    public void onSaveGroupFilter(List<String> groupFilter) {
+    public void onSaveGroupFilter(Set<UUID> groupFilter) {
         _prefs.setGroupFilter(groupFilter);
     }
 
@@ -1128,17 +1128,7 @@ public class MainActivity extends AegisActivity implements EntryListView.Listene
                     case R.id.action_delete:
                         Dialogs.showDeleteEntriesDialog(MainActivity.this, _selectedEntries, (d, which) -> {
                             deleteEntries(_selectedEntries);
-
+                            _entryListView.setGroups(_vaultManager.getVault().getUsedGroups());
-                            for (VaultEntry entry : _selectedEntries) {
-                                if (entry.getGroup() != null) {
-                                    TreeSet<String> groups = _vaultManager.getVault().getGroups();
-                                    if (!groups.contains(entry.getGroup())) {
-                                        _entryListView.setGroups(groups);
-                                        break;
-                                    }
-                                }
-                            }
-
                             mode.finish();
                         });
                         return true;

app/src/main/java/com/beemdevelopment/aegis/ui/components/DropdownCheckBoxes.java

@@ -18,19 +18,19 @@ import androidx.appcompat.widget.AppCompatAutoCompleteTextView;
 import com.beemdevelopment.aegis.R;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
-import java.util.TreeSet;
 import java.util.stream.Collectors;
 
-public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
+public class DropdownCheckBoxes<T> extends AppCompatAutoCompleteTextView {
     private @PluralsRes int _selectedCountPlural = R.plurals.dropdown_checkboxes_default_count;
 
     private boolean _allowFiltering = false;
 
-    private final List<String> _items = new ArrayList<>();
+    private final List<T> _items = new ArrayList<>();
-    private List<String> _visibleItems = new ArrayList<>();
+    private List<T> _visibleItems = new ArrayList<>();
-    private final Set<String> _checkedItems = new TreeSet<>();
+    private final Set<T> _checkedItems = new HashSet<>();
 
     private CheckboxAdapter _adapter;
 
@@ -70,7 +70,15 @@ public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
         }
     }
 
-    public void addItems(List<String> items, boolean startChecked) {
+    /**
+     * Add parameterized items to be displayed as a checkbox in the dropdown view
+     * the label for the checkbox is determined by the toString() method of the items
+     * you add.
+     *
+     * @param items a list of the items you want to show in the dropdown
+     * @param startChecked whether the checkbox should be checked initially
+     */
+    public void addItems(List<T> items, boolean startChecked) {
         _items.addAll(items);
         _visibleItems.addAll(items);
 
@@ -97,7 +105,7 @@ public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
         _selectedCountPlural = resId;
     }
 
-    public Set<String> getCheckedItems() {
+    public Set<T> getCheckedItems() {
         return _checkedItems;
     }
 
@@ -109,7 +117,7 @@ public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
         }
 
         @Override
-        public String getItem(int i) {
+        public T getItem(int i) {
             return _visibleItems.get(i);
         }
 
@@ -124,19 +132,18 @@ public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
                 convertView = LayoutInflater.from(getContext()).inflate(R.layout.dropdown_checkbox, viewGroup, false);
             }
 
-            String item = _visibleItems.get(i);
+            T item = _visibleItems.get(i);
 
             CheckBox checkBox = convertView.findViewById(R.id.checkbox_in_dropdown);
-            checkBox.setText(item);
+            checkBox.setText(item.toString());
+            checkBox.setTag(item);
             checkBox.setChecked(_checkedItems.contains(item));
 
             checkBox.setOnCheckedChangeListener((buttonView, isChecked) -> {
-                String label = buttonView.getText().toString();
-
                 if (isChecked) {
-                    _checkedItems.add(label);
+                    _checkedItems.add((T) buttonView.getTag());
                 } else {
-                    _checkedItems.remove(label);
+                    _checkedItems.remove((T) buttonView.getTag());
                 }
 
                 updateCheckedItemsCountText();
@@ -153,9 +160,9 @@ public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
                     FilterResults results = new FilterResults();
                     results.values = (query == null || query.toString().isEmpty())
                                    ? _items
-                                   : _items.stream().filter(str -> {
+                                   : _items.stream().filter(item -> {
                                                         String q = query.toString().toLowerCase();
-                                                        String strLower = str.toLowerCase();
+                                                        String strLower = item.toString().toLowerCase();
 
                                                         return strLower.contains(q);
                                                     })
@@ -166,7 +173,7 @@ public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
 
                 @Override
                 protected void publishResults(CharSequence charSequence, FilterResults filterResults) {
-                    _visibleItems = (List<String>) filterResults.values;
+                    _visibleItems = (List<T>) filterResults.values;
                     notifyDataSetChanged();
                 }
             };

app/src/main/java/com/beemdevelopment/aegis/ui/dialogs/Dialogs.java

@@ -25,6 +25,7 @@ import android.widget.TextView;
 import android.widget.Toast;
 
 import androidx.activity.ComponentActivity;
+import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 import androidx.appcompat.app.AlertDialog;
 
@@ -242,8 +243,8 @@ public class Dialogs {
         showTextInputDialog(context, titleId, 0, hintId, listener, null, isSecret);
     }
 
-    public static void showTextInputDialog(Context context, @StringRes int titleId, @StringRes int hintId, TextInputListener listener) {
+    public static void showTextInputDialog(Context context, @StringRes int titleId, @StringRes int hintId, TextInputListener listener, @Nullable DialogInterface.OnCancelListener onCancel) {
-        showTextInputDialog(context, titleId, hintId, listener, false);
+        showTextInputDialog(context, titleId, 0, hintId, listener, onCancel, false);
     }
 
     public static void showPasswordInputDialog(Context context, TextInputListener listener) {

app/src/main/java/com/beemdevelopment/aegis/ui/fragments/preferences/ImportExportPreferencesFragment.java

@@ -31,12 +31,14 @@ import com.beemdevelopment.aegis.ui.ImportEntriesActivity;
 import com.beemdevelopment.aegis.ui.TransferEntriesActivity;
 import com.beemdevelopment.aegis.ui.components.DropdownCheckBoxes;
 import com.beemdevelopment.aegis.ui.dialogs.Dialogs;
+import com.beemdevelopment.aegis.ui.models.VaultGroupModel;
 import com.beemdevelopment.aegis.ui.tasks.ExportTask;
 import com.beemdevelopment.aegis.ui.tasks.ImportFileTask;
 import com.beemdevelopment.aegis.vault.Vault;
 import com.beemdevelopment.aegis.vault.VaultBackupManager;
 import com.beemdevelopment.aegis.vault.VaultEntry;
 import com.beemdevelopment.aegis.vault.VaultFileCredentials;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 import com.beemdevelopment.aegis.vault.VaultRepository;
 import com.beemdevelopment.aegis.vault.VaultRepositoryException;
 import com.beemdevelopment.aegis.vault.slots.PasswordSlot;
@@ -48,12 +50,14 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.Random;
 import java.util.Set;
-import java.util.TreeSet;
+import java.util.UUID;
+import java.util.stream.Collectors;
 
 import javax.crypto.Cipher;
 
@@ -164,7 +168,7 @@ public class ImportExportPreferencesFragment extends PreferencesFragment {
         CheckBox checkBoxAccept = view.findViewById(R.id.checkbox_accept);
         CheckBox checkBoxExportAllGroups = view.findViewById(R.id.export_selected_groups);
         TextInputLayout groupsSelectionLayout = view.findViewById(R.id.group_selection_layout);
-        DropdownCheckBoxes groupsSelection = view.findViewById(R.id.group_selection_dropdown);
+        DropdownCheckBoxes<VaultGroupModel> groupsSelection = view.findViewById(R.id.group_selection_dropdown);
         TextView passwordInfoText = view.findViewById(R.id.text_separate_password);
         passwordInfoText.setVisibility(checkBoxEncrypt.isChecked() && isBackupPasswordSet ? View.VISIBLE : View.GONE);
         AutoCompleteTextView dropdown = view.findViewById(R.id.dropdown_export_format);
@@ -177,13 +181,13 @@ public class ImportExportPreferencesFragment extends PreferencesFragment {
             passwordInfoText.setVisibility(checkBoxEncrypt.isChecked() && isBackupPasswordSet ? View.VISIBLE : View.GONE);
         });
 
-        TreeSet<String> groups = _vaultManager.getVault().getGroups();
+        Collection<VaultGroup> groups = _vaultManager.getVault().getUsedGroups();
         if (groups.size() > 0) {
             checkBoxExportAllGroups.setVisibility(View.VISIBLE);
 
-            ArrayList<String> groupsArray = new ArrayList<>();
+            ArrayList<VaultGroupModel> groupsArray = new ArrayList<>();
-            groupsArray.add(getString(R.string.no_group));
+            groupsArray.add(new VaultGroupModel(getString(R.string.no_group)));
-            groupsArray.addAll(groups);
+            groupsArray.addAll(groups.stream().map(VaultGroupModel::new).collect(Collectors.toList()));
 
             groupsSelection.setCheckedItemsCountTextRes(R.plurals.export_groups_selected_count);
             groupsSelection.addItems(groupsArray, false);
@@ -319,17 +323,19 @@ public class ImportExportPreferencesFragment extends PreferencesFragment {
         Dialogs.showSecureDialog(dialog);
     }
 
-    private Vault.EntryFilter getVaultEntryFilter(DropdownCheckBoxes dropdownCheckBoxes) {
+    private Vault.EntryFilter getVaultEntryFilter(DropdownCheckBoxes<VaultGroupModel> dropdownCheckBoxes) {
-        Set<String> groups = new HashSet<>();
+        Set<UUID> groups = new HashSet<>();
-        for (String group: dropdownCheckBoxes.getCheckedItems()) {
+        for (VaultGroupModel group : dropdownCheckBoxes.getCheckedItems()) {
-            if (group.equals(getString(R.string.no_group))) {
+            groups.add(group.getUUID());
-                groups.add(null);
-            } else  {
-                groups.add(group);
-            }
         }
 
-        return groups.isEmpty() ? null : entry -> groups.contains(entry.getGroup());
+        return groups.isEmpty() ? null : entry -> {
+            if (entry.getGroups().isEmpty()) {
+                return groups.contains(null);
+            } else {
+                return entry.getGroups().stream().anyMatch(groups::contains);
+            }
+        };
     }
 
     private void startGoogleAuthenticatorStyleExport() {

app/src/main/java/com/beemdevelopment/aegis/ui/models/VaultGroupModel.java

@@ -0,0 +1,45 @@
+package com.beemdevelopment.aegis.ui.models;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import com.beemdevelopment.aegis.vault.VaultGroup;
+import java.io.Serializable;
+import java.util.UUID;
+
+public class VaultGroupModel implements Serializable {
+    private final VaultGroup _group;
+    private final String _placeholderName;
+
+    public VaultGroupModel(VaultGroup group) {
+        _group = group;
+        _placeholderName = null;
+    }
+
+    public VaultGroupModel(String placeholderName) {
+        _group = null;
+        _placeholderName = placeholderName;
+    }
+
+    public VaultGroup getGroup() {
+        return _group;
+    }
+
+    public String getName() {
+        return _group != null ? _group.getName() : _placeholderName;
+    }
+
+    public boolean isPlaceholder() {
+        return _group == null;
+    }
+
+    @Nullable
+    public UUID getUUID() {
+        return _group == null ? null : _group.getUUID();
+    }
+
+    @NonNull
+    @Override
+    public String toString() {
+        return getName();
+    }
+}

app/src/main/java/com/beemdevelopment/aegis/ui/views/EntryAdapter.java

@@ -39,6 +39,8 @@ import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
 import java.util.TreeSet;
 import java.util.UUID;
 
@@ -59,7 +61,7 @@ public class EntryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
     private boolean _tapToReveal;
     private int _tapToRevealTime;
     private CopyBehavior _copyBehavior;
-    private List<String> _groupFilter;
+    private Set<UUID> _groupFilter;
     private SortCategory _sortCategory;
     private ViewMode _viewMode;
     private String _searchFilter;
@@ -76,7 +78,7 @@ public class EntryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
         _entries = new ArrayList<>();
         _shownEntries = new ArrayList<>();
         _selectedEntries = new ArrayList<>();
-        _groupFilter = new ArrayList<>();
+        _groupFilter = new TreeSet<>();
         _holders = new ArrayList<>();
         _dimHandler = new Handler();
         _doubleTapHandler = new Handler();
@@ -246,12 +248,15 @@ public class EntryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
     }
 
     private boolean isEntryFiltered(VaultEntry entry) {
-        String group = entry.getGroup();
+        Set<UUID> groups = entry.getGroups();
         String issuer = entry.getIssuer().toLowerCase();
         String name = entry.getName().toLowerCase();
 
         if (!_groupFilter.isEmpty()) {
-            if (!_groupFilter.contains(group)) {
+            if (groups.isEmpty() && !_groupFilter.contains(null)) {
+                return true;
+            }
+            if (!groups.isEmpty() && _groupFilter.stream().filter(Objects::nonNull).noneMatch(groups::contains)) {
                 return true;
             }
         }
@@ -274,7 +279,7 @@ public class EntryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
         }
     }
 
-    public void setGroupFilter(@NonNull List<String> groups) {
+    public void setGroupFilter(@NonNull Set<UUID> groups) {
         if (_groupFilter.equals(groups)) {
             return;
         }
@@ -352,10 +357,6 @@ public class EntryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
         return (int) _shownEntries.stream().filter(VaultEntry::isFavorite).count();
     }
 
-    public void setGroups(TreeSet<String> groups) {
-        _view.setGroups(groups);
-    }
-
     @Override
     public void onItemDismiss(int position) {
 

app/src/main/java/com/beemdevelopment/aegis/ui/views/EntryListView.java

@@ -37,7 +37,10 @@ import com.beemdevelopment.aegis.helpers.UiRefresher;
 import com.beemdevelopment.aegis.otp.TotpInfo;
 import com.beemdevelopment.aegis.ui.dialogs.Dialogs;
 import com.beemdevelopment.aegis.ui.glide.IconLoader;
+import com.beemdevelopment.aegis.ui.models.VaultGroupModel;
+import com.beemdevelopment.aegis.util.UUIDMap;
 import com.beemdevelopment.aegis.vault.VaultEntry;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 import com.bumptech.glide.Glide;
 import com.bumptech.glide.ListPreloader;
 import com.bumptech.glide.RequestBuilder;
@@ -54,7 +57,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.TreeSet;
+import java.util.Set;
 import java.util.UUID;
 import java.util.stream.Collectors;
 
@@ -71,11 +74,11 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
     private TotpProgressBar _progressBar;
     private boolean _showProgress;
     private ViewMode _viewMode;
-    private TreeSet<String> _groups;
+    private Collection<VaultGroup> _groups;
     private LinearLayout _emptyStateView;
     private Chip _groupChip;
-    private List<String> _groupFilter;
+    private Set<UUID> _groupFilter;
-    private List<String> _prefGroupFilter;
+    private Set<UUID> _prefGroupFilter;
 
     private UiRefresher _refresher;
 
@@ -168,7 +171,7 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         super.onDestroyView();
     }
 
-    public void setGroupFilter(List<String> groups, boolean animate) {
+    public void setGroupFilter(Set<UUID> groups, boolean animate) {
         _groupFilter = groups;
         _adapter.setGroupFilter(groups);
         _touchCallback.setIsLongPressDragEnabled(_adapter.isDragAndDropAllowed());
@@ -334,7 +337,7 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         }
     }
 
-    public void setPrefGroupFilter(List<String> groupFilter) {
+    public void setPrefGroupFilter(Set<UUID> groupFilter) {
         _prefGroupFilter = groupFilter;
     }
 
@@ -465,17 +468,17 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         _recyclerView.scheduleLayoutAnimation();
     }
 
-    private void addChipTo(ChipGroup chipGroup, String group) {
+    private void addChipTo(ChipGroup chipGroup, VaultGroupModel group) {
         Chip chip = (Chip) getLayoutInflater().inflate(R.layout.chip_material, null, false);
-        chip.setText(group == null ? getString(R.string.no_group) : group);
+        chip.setText(group.getName());
         chip.setCheckable(true);
-        chip.setChecked(_groupFilter != null && _groupFilter.contains(group));
+        chip.setChecked(_groupFilter != null && _groupFilter.contains(group.getUUID()));
         chip.setCheckedIconVisible(true);
         chip.setOnCheckedChangeListener((group1, checkedId) -> {
-            List<String> groupFilter = getGroupFilter(chipGroup);
+            Set<UUID> groupFilter = getGroupFilter(chipGroup);
             setGroupFilter(groupFilter, true);
         });
-        chip.setTag(group == null ? new Object() : null);
+        chip.setTag(group);
         chipGroup.addView(chip);
     }
 
@@ -489,7 +492,7 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         Button saveButton = view.findViewById(R.id.btnSave);
         clearButton.setOnClickListener(v -> {
             chipGroup.clearCheck();
-            List<String> groupFilter = Collections.emptyList();
+            Set<UUID> groupFilter = Collections.emptySet();
             if (_listener != null) {
                 _listener.onSaveGroupFilter(groupFilter);
             }
@@ -498,7 +501,7 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         });
 
         saveButton.setOnClickListener(v -> {
-            List<String> groupFilter = getGroupFilter(chipGroup);
+            Set<UUID> groupFilter = getGroupFilter(chipGroup);
             if (_listener != null) {
                 _listener.onSaveGroupFilter(groupFilter);
             }
@@ -509,25 +512,23 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         _groupChip.setOnClickListener(v -> {
             chipGroup.removeAllViews();
 
-            for (String group : _groups) {
+            for (VaultGroup group : _groups) {
-                addChipTo(chipGroup, group);
+                addChipTo(chipGroup, new VaultGroupModel(group));
             }
-            addChipTo(chipGroup, null);
+            addChipTo(chipGroup, new VaultGroupModel(getString(R.string.no_group)));
 
             Dialogs.showSecureDialog(dialog);
         });
     }
 
-    private static List<String> getGroupFilter(ChipGroup chipGroup) {
+    private static Set<UUID> getGroupFilter(ChipGroup chipGroup) {
         return chipGroup.getCheckedChipIds().stream()
                 .map(i -> {
                     Chip chip = chipGroup.findViewById(i);
-                    if (chip.getTag() != null) {
+                    VaultGroupModel group = (VaultGroupModel) chip.getTag();
-                        return null;
+                    return group.getUUID();
-                    }
-                    return chip. getText().toString();
                 })
-                .collect(Collectors.toList());
+                .collect(Collectors.toSet());
     }
 
     private void updateGroupChip() {
@@ -543,29 +544,31 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         updateDividerDecoration();
     }
 
-    public void setGroups(TreeSet<String> groups) {
+    public void setGroups(Collection<VaultGroup> groups) {
         _groups = groups;
         _groupChip.setVisibility(_groups.isEmpty() ? View.GONE : View.VISIBLE);
         updateDividerDecoration();
 
         if (_prefGroupFilter != null) {
-            List<String> groupFilter = cleanGroupFilter(_prefGroupFilter);
+            Set<UUID> groupFilter = cleanGroupFilter(_prefGroupFilter);
             _prefGroupFilter = null;
             if (!groupFilter.isEmpty()) {
                 setGroupFilter(groupFilter, false);
             }
         } else if (_groupFilter != null) {
-            List<String> groupFilter = cleanGroupFilter(_groupFilter);
+            Set<UUID> groupFilter = cleanGroupFilter(_groupFilter);
             if (!_groupFilter.equals(groupFilter)) {
                 setGroupFilter(groupFilter, true);
             }
         }
     }
 
-    private List<String> cleanGroupFilter(List<String> groupFilter) {
+    private Set<UUID> cleanGroupFilter(Set<UUID> groupFilter) {
-       return groupFilter.stream()
+        Set<UUID> groupUuids = _groups.stream().map(UUIDMap.Value::getUUID).collect(Collectors.toSet());
-                .filter(g -> g == null || _groups.contains(g))
+
-                .collect(Collectors.toList());
+        return groupFilter.stream()
+                .filter(g -> g == null || groupUuids.contains(g))
+                .collect(Collectors.toSet());
     }
 
     private void updateDividerDecoration() {
@@ -616,7 +619,7 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         void onSelect(VaultEntry entry);
         void onDeselect(VaultEntry entry);
         void onListChange();
-        void onSaveGroupFilter(List<String> groupFilter);
+        void onSaveGroupFilter(Set<UUID> groupFilter);
         void onEntryListTouch();
     }
 

app/src/main/java/com/beemdevelopment/aegis/ui/views/GroupAdapter.java

@@ -7,19 +7,20 @@ import android.view.ViewGroup;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.beemdevelopment.aegis.R;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 
 import java.util.ArrayList;
 
 public class GroupAdapter extends RecyclerView.Adapter<GroupHolder> {
     private GroupAdapter.Listener _listener;
-    private ArrayList<String> _groups;
+    private ArrayList<VaultGroup> _groups;
 
     public GroupAdapter(GroupAdapter.Listener listener) {
         _listener = listener;
         _groups = new ArrayList<>();
     }
 
-    public void addGroup(String group) {
+    public void addGroup(VaultGroup group) {
         _groups.add(group);
 
         int position = getItemCount() - 1;
@@ -30,7 +31,7 @@ public class GroupAdapter extends RecyclerView.Adapter<GroupHolder> {
         }
     }
 
-    public void removeGroup(String group) {
+    public void removeGroup(VaultGroup group) {
         int position = _groups.indexOf(group);
         _groups.remove(position);
         notifyItemRemoved(position);
@@ -57,6 +58,6 @@ public class GroupAdapter extends RecyclerView.Adapter<GroupHolder> {
     }
 
     public interface Listener {
-        void onRemoveGroup(String group);
+        void onRemoveGroup(VaultGroup group);
     }
 }

app/src/main/java/com/beemdevelopment/aegis/ui/views/GroupHolder.java

@@ -7,6 +7,7 @@ import android.widget.TextView;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.beemdevelopment.aegis.R;
+import com.beemdevelopment.aegis.vault.VaultGroup;
 
 public class GroupHolder extends RecyclerView.ViewHolder {
     private TextView _slotName;
@@ -18,8 +19,8 @@ public class GroupHolder extends RecyclerView.ViewHolder {
         _buttonDelete = view.findViewById(R.id.button_delete);
     }
 
-    public void setData(String groupName) {
+    public void setData(VaultGroup group) {
-        _slotName.setText(groupName);
+        _slotName.setText(group.getName());
     }
 
     public void setOnDeleteClickListener(View.OnClickListener listener) {

app/src/main/java/com/beemdevelopment/aegis/util/UUIDMap.java

@@ -9,6 +9,7 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Objects;
 import java.util.UUID;
 
 /**
@@ -99,7 +100,14 @@ public class UUIDMap <T extends UUIDMap.Value> implements Iterable<T>, Serializa
      * Reports whether the internal map contains a value with the UUID of the given value.
      */
     public boolean has(T value) {
-        return _map.containsKey(value.getUUID());
+        return has(value.getUUID());
+    }
+
+    /**
+     * Reports whether the internal map contains a value with the given UUID.
+     */
+    public boolean has(UUID uuid) {
+        return _map.containsKey(uuid);
     }
 
     /**
@@ -161,7 +169,7 @@ public class UUIDMap <T extends UUIDMap.Value> implements Iterable<T>, Serializa
                 return false;
             }
 
-            return getUUID().equals(((Value) o).getUUID());
+            return Objects.equals(getUUID(), ((Value) o).getUUID());
         }
     }
 }

app/src/main/java/com/beemdevelopment/aegis/vault/Vault.java

@@ -8,9 +8,13 @@ import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.util.Optional;
+import java.util.UUID;
+
 public class Vault {
-    private static final int VERSION = 2;
+    private static final int VERSION = 3;
-    private UUIDMap<VaultEntry> _entries = new UUIDMap<>();
+    private final UUIDMap<VaultEntry> _entries = new UUIDMap<>();
+    private final UUIDMap<VaultGroup> _groups = new UUIDMap<>();
 
     public JSONObject toJson() {
         return toJson(null);
@@ -18,16 +22,24 @@ public class Vault {
 
     public JSONObject toJson(@Nullable EntryFilter filter) {
         try {
-            JSONArray array = new JSONArray();
+            JSONArray entriesArray = new JSONArray();
             for (VaultEntry e : _entries) {
                 if (filter == null || filter.includeEntry(e)) {
-                    array.put(e.toJson());
+                    entriesArray.put(e.toJson());
                 }
             }
 
+            // Always include all groups, even if they're not assigned to any entry (before or after the entry filter)
+            JSONArray groupsArray = new JSONArray();
+            for (VaultGroup group : _groups) {
+                groupsArray.put(group.toJson());
+            }
+
             JSONObject obj = new JSONObject();
             obj.put("version", VERSION);
-            obj.put("entries", array);
+            obj.put("entries", entriesArray);
+            obj.put("groups", groupsArray);
+
             return obj;
         } catch (JSONException e) {
             throw new RuntimeException(e);
@@ -37,6 +49,7 @@ public class Vault {
     public static Vault fromJson(JSONObject obj) throws VaultException {
         Vault vault = new Vault();
         UUIDMap<VaultEntry> entries = vault.getEntries();
+        UUIDMap<VaultGroup> groups = vault.getGroups();
 
         try {
             int ver = obj.getInt("version");
@@ -44,9 +57,28 @@ public class Vault {
                 throw new VaultException("Unsupported version");
             }
 
+            if (obj.has("groups")) {
+                JSONArray groupsArray = obj.getJSONArray("groups");
+                for (int i = 0; i < groupsArray.length(); i++) {
+                    VaultGroup group = VaultGroup.fromJson(groupsArray.getJSONObject(i));
+                    if (!groups.has(group)) {
+                        groups.add(group);
+                    }
+                }
+            }
+
             JSONArray array = obj.getJSONArray("entries");
             for (int i = 0; i < array.length(); i++) {
                 VaultEntry entry = VaultEntry.fromJson(array.getJSONObject(i));
+                vault.migrateOldGroup(entry);
+
+                // check the vault has a group corresponding to each one the entry claims to be in
+                for (UUID groupUuid: entry.getGroups()) {
+                    if (!groups.has(groupUuid)) {
+                        entry.removeGroup(groupUuid);
+                    }
+                }
+
                 entries.add(entry);
             }
         } catch (VaultEntryException | JSONException e) {
@@ -56,10 +88,33 @@ public class Vault {
         return vault;
     }
 
+    public void migrateOldGroup(VaultEntry entry) {
+        if (entry.getOldGroup() != null) {
+            Optional<VaultGroup> optGroup = getGroups().getValues()
+                                                 .stream()
+                                                 .filter(g -> g.getName().equals(entry.getOldGroup()))
+                                                 .findFirst();
+
+            if (optGroup.isPresent()) {
+                entry.addGroup(optGroup.get().getUUID());
+            } else {
+                VaultGroup group = new VaultGroup(entry.getOldGroup());
+                getGroups().add(group);
+                entry.addGroup(group.getUUID());
+            }
+
+            entry.setOldGroup(null);
+        }
+    }
+
     public UUIDMap<VaultEntry> getEntries() {
         return _entries;
     }
 
+    public UUIDMap<VaultGroup> getGroups() {
+        return _groups;
+    }
+
     public interface EntryFilter {
         boolean includeEntry(VaultEntry entry);
     }

app/src/main/java/com/beemdevelopment/aegis/vault/VaultEntry.java

@@ -10,23 +10,26 @@ import com.beemdevelopment.aegis.otp.TotpInfo;
 import com.beemdevelopment.aegis.util.JsonUtils;
 import com.beemdevelopment.aegis.util.UUIDMap;
 
+import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
 import java.util.Arrays;
-import java.util.Objects;
+import java.util.Set;
+import java.util.TreeSet;
 import java.util.UUID;
 
 public class VaultEntry extends UUIDMap.Value {
     private String _name = "";
     private String _issuer = "";
-    private String _group;
     private OtpInfo _info;
     private byte[] _icon;
     private IconType _iconType = IconType.INVALID;
     private boolean _isFavorite;
     private int _usageCount;
     private String _note = "";
+    private String _oldGroup;
+    private Set<UUID> _groups = new TreeSet<>();
 
     private VaultEntry(UUID uuid, OtpInfo info) {
         super(uuid);
@@ -44,13 +47,6 @@ public class VaultEntry extends UUIDMap.Value {
         setIssuer(issuer);
     }
 
-    public VaultEntry(OtpInfo info, String name, String issuer, String group) {
-        this(info);
-        setName(name);
-        setIssuer(issuer);
-        setGroup(group);
-    }
-
     public VaultEntry(GoogleAuthInfo info) {
         this(info.getOtpInfo(), info.getAccountName(), info.getIssuer());
     }
@@ -63,12 +59,18 @@ public class VaultEntry extends UUIDMap.Value {
             obj.put("uuid", getUUID().toString());
             obj.put("name", _name);
             obj.put("issuer", _issuer);
-            obj.put("group", _group);
             obj.put("note", _note);
             obj.put("favorite", _isFavorite);
             obj.put("icon", _icon == null ? JSONObject.NULL : Base64.encode(_icon));
             obj.put("icon_mime", _icon == null ? null : _iconType.toMimeType());
             obj.put("info", _info.toJson());
+
+            JSONArray groupUuids = new JSONArray();
+            for (UUID uuid : _groups) {
+                groupUuids.put(uuid.toString());
+            }
+            obj.put("groups", groupUuids);
+
         } catch (JSONException e) {
             throw new RuntimeException(e);
         }
@@ -90,10 +92,21 @@ public class VaultEntry extends UUIDMap.Value {
             VaultEntry entry = new VaultEntry(uuid, info);
             entry.setName(obj.getString("name"));
             entry.setIssuer(obj.getString("issuer"));
-            entry.setGroup(obj.optString("group", null));
             entry.setNote(obj.optString("note", ""));
             entry.setIsFavorite(obj.optBoolean("favorite", false));
 
+            // If the entry contains a list of group UUID's, assume conversion from the
+            // old group system has already taken place and ignore the old group field.
+            if (obj.has("groups")) {
+                JSONArray groups = obj.getJSONArray("groups");
+                for (int i = 0; i < groups.length(); i++) {
+                    String groupUuid = groups.getString(i);
+                    entry.addGroup(UUID.fromString(groupUuid));
+                }
+            } else if (obj.has("group")) {
+                entry.setOldGroup(JsonUtils.optString(obj, "group"));
+            }
+
             Object icon = obj.get("icon");
             if (icon != JSONObject.NULL) {
                 String mime = JsonUtils.optString(obj, "icon_mime");
@@ -121,8 +134,8 @@ public class VaultEntry extends UUIDMap.Value {
         return _issuer;
     }
 
-    public String getGroup() {
+    public Set<UUID> getGroups() {
-        return _group;
+        return _groups;
     }
 
     public byte[] getIcon() {
@@ -153,8 +166,22 @@ public class VaultEntry extends UUIDMap.Value {
         _issuer = issuer;
     }
 
-    public void setGroup(String group) {
+    public void addGroup(UUID group) {
-        _group = group;
+        if (group == null) {
+            throw new AssertionError("Attempt to add null group to entry's group list");
+        }
+        _groups.add(group);
+    }
+
+    public void removeGroup(UUID group) {
+        _groups.remove(group);
+    }
+
+    public void setGroups(Set<UUID> groups) {
+        if (groups.contains(null)) {
+            throw new AssertionError("Attempt to add null group to entry's group list");
+        }
+        _groups = groups;
     }
 
     public void setInfo(OtpInfo info) {
@@ -176,6 +203,14 @@ public class VaultEntry extends UUIDMap.Value {
 
     public void setIsFavorite(boolean isFavorite) { _isFavorite = isFavorite; }
 
+    void setOldGroup(String oldGroup) {
+        _oldGroup = oldGroup;
+    }
+
+    String getOldGroup() {
+        return _oldGroup;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (!(o instanceof VaultEntry)) {
@@ -194,12 +229,12 @@ public class VaultEntry extends UUIDMap.Value {
     public boolean equivalates(VaultEntry entry) {
         return getName().equals(entry.getName())
                 && getIssuer().equals(entry.getIssuer())
-                && Objects.equals(getGroup(), entry.getGroup())
                 && getInfo().equals(entry.getInfo())
                 && Arrays.equals(getIcon(), entry.getIcon())
                 && getIconType().equals(entry.getIconType())
                 && getNote().equals(entry.getNote())
-                && isFavorite() == entry.isFavorite();
+                && isFavorite() == entry.isFavorite()
+                && getGroups().equals(entry.getGroups());
     }
 
     /**

app/src/main/java/com/beemdevelopment/aegis/vault/VaultGroup.java

@@ -0,0 +1,69 @@
+package com.beemdevelopment.aegis.vault;
+
+import com.beemdevelopment.aegis.util.UUIDMap;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.UUID;
+
+public class VaultGroup extends UUIDMap.Value {
+    private String _name;
+
+    private VaultGroup(UUID uuid, String name) {
+        super(uuid);
+        _name = name;
+    }
+
+    public VaultGroup(String name) {
+        super();
+        _name = name;
+    }
+
+    public JSONObject toJson() {
+        JSONObject obj = new JSONObject();
+
+        try {
+            obj.put("uuid", getUUID().toString());
+            obj.put("name", _name);
+        } catch (JSONException e) {
+            throw new RuntimeException(e);
+        }
+
+        return obj;
+    }
+
+    public static VaultGroup fromJson(JSONObject obj) throws VaultEntryException {
+        try {
+            UUID uuid = UUID.fromString(obj.getString("uuid"));
+            String groupName = obj.getString("name");
+
+            return new VaultGroup(uuid, groupName);
+        } catch (JSONException e) {
+            throw new VaultEntryException(e);
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof VaultGroup)) {
+            return false;
+        }
+
+        VaultGroup entry = (VaultGroup) o;
+        return super.equals(entry) && getName().equals(entry.getName());
+    }
+
+    public String getName() {
+        return _name;
+    }
+
+    public void setName(String name) {
+        _name = name;
+    }
+
+    @Override
+    public String toString() {
+        return _name;
+    }
+}

app/src/main/java/com/beemdevelopment/aegis/vault/VaultRepository.java

@@ -20,9 +20,9 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.PrintStream;
 import java.nio.charset.StandardCharsets;
-import java.text.Collator;
 import java.util.Collection;
-import java.util.TreeSet;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.UUID;
 import java.util.stream.Collectors;
 
@@ -220,6 +220,8 @@ public class VaultRepository {
     }
 
     public void addEntry(VaultEntry entry) {
+        // Entries added by importing a file may contain an old group that needs to be migrated
+        _vault.migrateOldGroup(entry);
         _vault.getEntries().add(entry);
     }
 
@@ -231,8 +233,12 @@ public class VaultRepository {
         return _vault.getEntries().remove(entry);
     }
 
-    public void wipeEntries() {
+    /**
+     * Wipes all entries and groups from the vault.
+     */
+    public void wipeContents() {
         _vault.getEntries().wipe();
+        _vault.getGroups().wipe();
     }
 
     public VaultEntry replaceEntry(VaultEntry entry) {
@@ -240,8 +246,8 @@ public class VaultRepository {
     }
 
     /**
-      * Moves entry1 to the position of entry2.
+     * Moves entry1 to the position of entry2.
-      */
+     */
     public void moveEntry(VaultEntry entry1, VaultEntry entry2) {
         _vault.getEntries().move(entry1, entry2);
     }
@@ -254,15 +260,54 @@ public class VaultRepository {
         return _vault.getEntries().getValues();
     }
 
-    public TreeSet<String> getGroups() {
+    public void addGroup(VaultGroup group) {
-        TreeSet<String> groups = new TreeSet<>(Collator.getInstance());
+        _vault.getGroups().add(group);
+    }
+
+    public VaultGroup getGroupByUUID(UUID uuid) {
+        return _vault.getGroups().getByUUID(uuid);
+    }
+
+    @Nullable
+    public VaultGroup findGroupByUUID(UUID uuid) {
+        return _vault.getGroups().has(uuid) ? _vault.getGroups().getByUUID(uuid) : null;
+    }
+
+    @Nullable
+    public VaultGroup findGroupByName(String name) {
+        return _vault.getGroups().getValues()
+                .stream()
+                .filter(g -> g.getName().equals(name))
+                .findFirst()
+                .orElse(null);
+    }
+
+    public void removeGroup(UUID groupUuid) {
+        VaultGroup group = _vault.getGroups().getByUUID(groupUuid);
+        removeGroup(group);
+    }
+
+    public void removeGroup(VaultGroup group) {
         for (VaultEntry entry : getEntries()) {
-            String group = entry.getGroup();
+            entry.removeGroup(group.getUUID());
-            if (group != null) {
-                groups.add(group);
-            }
         }
-        return groups;
+
+        _vault.getGroups().remove(group);
+    }
+
+    public Collection<VaultGroup> getGroups() {
+        return _vault.getGroups().getValues();
+    }
+
+    public Collection<VaultGroup> getUsedGroups() {
+        Set<UUID> usedGroups = new HashSet<>();
+        for (VaultEntry entry : getEntries()) {
+            usedGroups.addAll(entry.getGroups());
+        }
+
+        return getGroups().stream()
+                .filter(vg -> usedGroups.contains(vg.getUUID()))
+                .collect(Collectors.toList());
     }
 
     public VaultFileCredentials getCredentials() {

app/src/main/res/menu/menu_groups.xml

@@ -3,6 +3,10 @@
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     tools:context="com.beemdevelopment.aegis.ui.GroupManagerActivity">
+    <item
+        android:id="@+id/action_delete_unused_groups"
+        app:showAsAction="collapseActionView"
+        android:title="@string/remove_unused_groups"/>
     <item
         android:id="@+id/action_save"
         app:showAsAction="ifRoom"

app/src/main/res/values/strings.xml

@@ -283,6 +283,8 @@
     <string name="unlocking_vault">Unlocking the vault</string>
     <string name="remove_group">Remove group</string>
     <string name="remove_group_description">Are you sure you want to remove this group? Entries in this group will automatically switch to \'No group\'.</string>
+    <string name="remove_unused_groups">Delete unused groups</string>
+    <string name="remove_unused_groups_description">Are you sure you want to delete all groups that are not assigned to an entry?</string>
     <string name="remove_icon_pack">Remove icon pack</string>
     <string name="remove_icon_pack_description">Are you sure you want to remove this icon pack? Entries that use icons from this pack will not be affected.</string>
     <string name="details">Details</string>

app/src/test/java/com/beemdevelopment/aegis/vault/VaultTest.java

@@ -0,0 +1,71 @@
+package com.beemdevelopment.aegis.vault;
+
+import static org.junit.Assert.assertEquals;
+
+import com.beemdevelopment.aegis.util.IOUtils;
+
+import org.junit.Test;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class VaultTest {
+    @Test
+    public void testGroupConversion()
+            throws IOException, VaultFileException, VaultException {
+        Vault vault;
+        try (InputStream inStream = getClass().getResourceAsStream("aegis_plain_grouped_v2.json")) {
+            byte[] bytes = IOUtils.readAll(inStream);
+            VaultFile file = VaultFile.fromBytes(bytes);
+            vault = Vault.fromJson(file.getContent());
+        }
+
+        checkGroups(vault);
+
+        // After saving to and loading from the new format, the same checks should still pass
+        vault = Vault.fromJson(vault.toJson());
+        checkGroups(vault);
+    }
+
+    private static void checkGroups(Vault vault) {
+        // No old groups should be present anymore
+        assertEquals(0, vault.getEntries().getValues().stream()
+                .filter(e -> e.getOldGroup() != null)
+                .count());
+
+        // New groups should have been created, and groups with the same name
+        // should have been merged into a single group
+        assertEquals(2, vault.getGroups().getValues().size());
+
+        // Only one group with name group1
+        List<VaultGroup> foundGroups = vault.getGroups().getValues().stream()
+                .filter(g -> g.getName().equals("group1"))
+                .collect(Collectors.toList());
+        assertEquals(1, foundGroups.size());
+        VaultGroup group1 = foundGroups.get(0);
+
+        // Only one group with name group2
+        foundGroups = vault.getGroups().getValues().stream()
+                .filter(g -> g.getName().equals("group2"))
+                .collect(Collectors.toList());
+        assertEquals(1, foundGroups.size());
+        VaultGroup group2 = foundGroups.get(0);
+
+        // Two entries in group1
+        assertEquals(2, vault.getEntries().getValues().stream()
+                .filter(e -> e.getGroups().contains(group1.getUUID()))
+                .count());
+
+        // One entry in group2
+        assertEquals(1, vault.getEntries().getValues().stream()
+                .filter(e -> e.getGroups().contains(group2.getUUID()))
+                .count());
+
+        // Rest of the entries in no groups
+        assertEquals(vault.getEntries().getValues().size() - 3, vault.getEntries().getValues().stream()
+                .filter(e -> e.getGroups().isEmpty())
+                .count());
+    }
+}

app/src/test/resources/com/beemdevelopment/aegis/vault/aegis_plain_grouped_v2.json

@@ -0,0 +1,117 @@
+{
+    "version": 1,
+    "header": {
+        "slots": null,
+        "params": null
+    },
+    "db": {
+        "version": 2,
+        "entries": [
+            {
+                "type": "totp",
+                "uuid": "3ae6f1ad-2e65-4ed2-a953-1ec0dff2386d",
+                "name": "Mason",
+                "issuer": "Deno",
+                "icon": null,
+                "icon_mime": null,
+                "group": "group1",
+                "info": {
+                    "secret": "4SJHB4GSD43FZBAI7C2HLRJGPQ",
+                    "algo": "SHA1",
+                    "digits": 6,
+                    "period": 30
+                }
+            },
+            {
+                "type": "totp",
+                "uuid": "84b55971-a3d2-4173-a5bb-0aea113dbc17",
+                "name": "James",
+                "issuer": "SPDX",
+                "icon": null,
+                "icon_mime": null,
+                "group": null,
+                "info": {
+                    "secret": "5OM4WOOGPLQEF6UGN3CPEOOLWU",
+                    "algo": "SHA256",
+                    "digits": 7,
+                    "period": 20
+                }
+            },
+            {
+                "type": "totp",
+                "uuid": "3deaff2e-f181-4837-80e1-fdf0c54e9363",
+                "name": "Elijah",
+                "issuer": "Airbnb",
+                "icon": null,
+                "icon_mime": null,
+                "group": "group1",
+                "info": {
+                    "secret": "7ELGJSGXNCCTV3O6LKJWYFV2RA",
+                    "algo": "SHA512",
+                    "digits": 8,
+                    "period": 50
+                }
+            },
+            {
+                "type": "hotp",
+                "uuid": "0a8c0571-ff6f-4b02-aa4b-50553b4fb4fe",
+                "name": "James",
+                "issuer": "Issuu",
+                "icon": null,
+                "icon_mime": null,
+                "group": "group2",
+                "info": {
+                    "secret": "YOOMIXWS5GN6RTBPUFFWKTW5M4",
+                    "algo": "SHA1",
+                    "digits": 6,
+                    "counter": 1
+                }
+            },
+            {
+                "type": "hotp",
+                "uuid": "03e572f2-8ebd-44b0-a57e-e958af74815d",
+                "name": "Benjamin",
+                "issuer": "Air Canada",
+                "icon": null,
+                "icon_mime": null,
+                "group": null,
+                "info": {
+                    "secret": "KUVJJOM753IHTNDSZVCNKL7GII",
+                    "algo": "SHA256",
+                    "digits": 7,
+                    "counter": 50
+                }
+            },
+            {
+                "type": "hotp",
+                "uuid": "b25f8815-007f-40f7-a700-ce058ac05435",
+                "name": "Mason",
+                "issuer": "WWE",
+                "icon": null,
+                "icon_mime": null,
+                "group": null,
+                "info": {
+                    "secret": "5VAML3X35THCEBVRLV24CGBKOY",
+                    "algo": "SHA512",
+                    "digits": 8,
+                    "counter": 10300
+                }
+            },
+            {
+                "type": "steam",
+                "uuid": "5b11ae3b-6fc3-4d46-8ca7-cf0aea7de920",
+                "name": "Sophia",
+                "issuer": "Boeing",
+                "icon": null,
+                "icon_mime": null,
+                "group": null,
+                "info": {
+                    "secret": "JRZCL47CMXVOQMNPZR2F7J4RGI",
+                    "algo": "SHA1",
+                    "digits": 5,
+                    "period": 30
+                }
+            }
+        ]
+    }
+}