Add a language option to the preference menu

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

@@ -2,8 +2,12 @@ package com.beemdevelopment.aegis;
 
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.content.res.Resources;
+import android.os.Build;
 import android.preference.PreferenceManager;
 
+import java.util.Locale;
+
 public class Preferences {
     private SharedPreferences _prefs;
 
@@ -70,4 +74,18 @@ public class Preferences {
     public int getTimeout() {
         return _prefs.getInt("pref_timeout", -1);
     }
+
+    public Locale getLocale() {
+        String lang = _prefs.getString("pref_lang", "system");
+
+        if (lang.equals("system")) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+                return Resources.getSystem().getConfiguration().getLocales().get(0);
+            } else {
+                return Resources.getSystem().getConfiguration().locale;
+            }
+        }
+
+        return new Locale(lang);
+    }
 }

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

@@ -2,6 +2,7 @@ package com.beemdevelopment.aegis.ui;
 
 import android.animation.ValueAnimator;
 import android.content.Intent;
+import android.content.res.Configuration;
 import android.os.Build;
 import android.os.Bundle;
 import android.provider.Settings;
@@ -16,6 +17,8 @@ import com.beemdevelopment.aegis.Theme;
 import androidx.annotation.CallSuper;
 import androidx.appcompat.app.AppCompatActivity;
 
+import java.util.Locale;
+
 public abstract class AegisActivity extends AppCompatActivity implements AegisApplication.LockListener {
     private boolean _resumed;
     private AegisApplication _app;
@@ -24,8 +27,10 @@ public abstract class AegisActivity extends AppCompatActivity implements AegisAp
     protected void onCreate(Bundle savedInstanceState) {
         _app = (AegisApplication) getApplication();
 
-        // set the theme and create the activity
-        setPreferredTheme(getPreferences().getCurrentTheme());
+        // set the theme and locale before creating the activity
+        Preferences prefs = getPreferences();
+        setPreferredTheme(prefs.getCurrentTheme());
+        setLocale(prefs.getLocale());
         super.onCreate(savedInstanceState);
 
         // if the app was killed, relaunch MainActivity and close everything else
@@ -97,6 +102,15 @@ public abstract class AegisActivity extends AppCompatActivity implements AegisAp
         }
     }
 
+    protected void setLocale(Locale locale) {
+        Locale.setDefault(locale);
+
+        Configuration config = new Configuration();
+        config.locale = locale;
+
+        getBaseContext().getResources().updateConfiguration(config, getBaseContext().getResources().getDisplayMetrics());
+    }
+
     /**
      * Reports whether this Activity has been resumed. (i.e. onResume was called)
      */

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

@@ -117,6 +117,13 @@ public class PreferencesFragment extends PreferenceFragmentCompat {
             }
         });
 
+        Preference langPreference = findPreference("pref_lang");
+        langPreference.setOnPreferenceChangeListener((preference, newValue) -> {
+            _result.putExtra("needsRecreate", true);
+            getActivity().recreate();
+            return true;
+        });
+
         int currentViewMode = app.getPreferences().getCurrentViewMode().ordinal();
         Preference viewModePreference = findPreference("pref_view_mode");
         viewModePreference.setSummary(String.format("%s: %s", getString(R.string.selected), getResources().getStringArray(R.array.view_mode_titles)[currentViewMode]));

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

@@ -29,4 +29,21 @@
         <item>@string/compact_mode_title</item>
         <item>@string/small_mode_title</item>
     </string-array>
+
+    <string-array name="pref_lang_entries">
+        <item>System default</item>
+        <item>Dutch</item>
+        <item>English</item>
+        <item>French</item>
+        <item>Russian</item>
+    </string-array>
+
+    <string-array name="pref_lang_values" translatable="false">
+        <item>system</item>
+        <item>nl</item>
+        <item>en</item>
+        <item>fr</item>
+        <item>ru</item>
+    </string-array>
+
 </resources>

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

@@ -15,6 +15,7 @@
     <string name="pref_tools_group_title">Tools</string>
     <string name="pref_select_theme_title">Theme</string>
     <string name="pref_view_mode_title">View mode</string>
+    <string name="pref_lang_title">Language</string>
     <string name="pref_account_name_title">Show the account name</string>
     <string name="pref_account_name_summary">Enable this to show the account name next to the issuer</string>
     <string name="pref_timeout_title">Timeout</string>

app/src/main/res/xml/preferences.xml

@@ -19,6 +19,15 @@
             android:title="@string/pref_view_mode_title"
             app:iconSpaceReserved="false"/>
 
+        <ListPreference
+            android:key="pref_lang"
+            android:title="@string/pref_lang_title"
+            android:summary="%s"
+            android:entries="@array/pref_lang_entries"
+            android:entryValues="@array/pref_lang_values"
+            android:defaultValue="system"
+            app:iconSpaceReserved="false"/>
+
         <androidx.preference.SwitchPreferenceCompat
             android:defaultValue="false"
             android:key="pref_account_name"