convert inputmethodcommon to kotlin

app/build.gradle

@@ -1,11 +1,13 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion 29
 
     defaultConfig {
         applicationId "org.dslul.openboard.inputmethod.latin"
-        minSdkVersion 14
+        minSdkVersion 19
         targetSdkVersion 29
         versionCode 4
         versionName "1.2"
@@ -36,4 +38,9 @@ android {
 dependencies {
     implementation 'com.google.code.findbugs:jsr305:3.0.2'
     implementation 'androidx.legacy:legacy-support-v4:1.0.0'
+    implementation "androidx.core:core-ktx:1.1.0"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}
+repositories {
+    mavenCentral()
 }

app/src/main/java/org/dslul/openboard/inputmethod/annotations/ExternallyReferenced.kt

@@ -13,12 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-package org.dslul.openboard.inputmethod.annotations;
+package org.dslul.openboard.inputmethod.annotations
 
 /**
  * Denotes that the class, method or field should not be eliminated by ProGuard,
  * because it is externally referenced. (See proguard.flags)
  */
-public @interface ExternallyReferenced {
-}
+annotation class ExternallyReferenced

app/src/main/java/org/dslul/openboard/inputmethod/annotations/UsedForTesting.kt

@@ -13,12 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-package org.dslul.openboard.inputmethod.annotations;
+package org.dslul.openboard.inputmethod.annotations
 
 /**
  * Denotes that the class, method or field should not be eliminated by ProGuard,
  * so that unit tests can access it. (See proguard.flags)
  */
-public @interface UsedForTesting {
-}
+annotation class UsedForTesting

app/src/main/java/org/dslul/openboard/inputmethodcommon/InputMethodSettingsActivity.java

@@ -1,94 +0,0 @@
-/*
- * Copyright (C) 2011 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License
- */
-
-package org.dslul.openboard.inputmethodcommon;
-
-import android.graphics.drawable.Drawable;
-import android.os.Bundle;
-import android.preference.PreferenceActivity;
-
-/**
- * This is a helper class for an IME's settings preference activity. It's recommended for every
- * IME to have its own settings preference activity which inherits this class.
- */
-public abstract class InputMethodSettingsActivity extends PreferenceActivity
-        implements InputMethodSettingsInterface {
-    private final InputMethodSettingsImpl mSettings = new InputMethodSettingsImpl();
-    @SuppressWarnings("deprecation")
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        setPreferenceScreen(getPreferenceManager().createPreferenceScreen(this));
-        mSettings.init(this, getPreferenceScreen());
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setInputMethodSettingsCategoryTitle(int resId) {
-        mSettings.setInputMethodSettingsCategoryTitle(resId);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setInputMethodSettingsCategoryTitle(CharSequence title) {
-        mSettings.setInputMethodSettingsCategoryTitle(title);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerTitle(int resId) {
-        mSettings.setSubtypeEnablerTitle(resId);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerTitle(CharSequence title) {
-        mSettings.setSubtypeEnablerTitle(title);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerIcon(int resId) {
-        mSettings.setSubtypeEnablerIcon(resId);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerIcon(Drawable drawable) {
-        mSettings.setSubtypeEnablerIcon(drawable);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void onResume() {
-        super.onResume();
-        mSettings.updateSubtypeEnabler();
-    }
-}

app/src/main/java/org/dslul/openboard/inputmethodcommon/InputMethodSettingsActivity.kt

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+package org.dslul.openboard.inputmethodcommon
+
+import android.graphics.drawable.Drawable
+import android.os.Bundle
+import android.preference.PreferenceActivity
+
+/**
+ * This is a helper class for an IME's settings preference activity. It's recommended for every
+ * IME to have its own settings preference activity which inherits this class.
+ */
+abstract class InputMethodSettingsActivity : PreferenceActivity(), InputMethodSettingsInterface {
+    private val mSettings = InputMethodSettingsImpl()
+    public override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        preferenceScreen = preferenceManager.createPreferenceScreen(this)
+        mSettings.init(this, preferenceScreen)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setInputMethodSettingsCategoryTitle(resId: Int) {
+        mSettings.setInputMethodSettingsCategoryTitle(resId)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setInputMethodSettingsCategoryTitle(title: CharSequence?) {
+        mSettings.setInputMethodSettingsCategoryTitle(title)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerTitle(resId: Int) {
+        mSettings.setSubtypeEnablerTitle(resId)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerTitle(title: CharSequence?) {
+        mSettings.setSubtypeEnablerTitle(title)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerIcon(resId: Int) {
+        mSettings.setSubtypeEnablerIcon(resId)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerIcon(drawable: Drawable?) {
+        mSettings.setSubtypeEnablerIcon(drawable)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public override fun onResume() {
+        super.onResume()
+        mSettings.updateSubtypeEnabler()
+    }
+}

app/src/main/java/org/dslul/openboard/inputmethodcommon/InputMethodSettingsFragment.java

@@ -1,95 +0,0 @@
-/*
- * Copyright (C) 2011 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.dslul.openboard.inputmethodcommon;
-
-import android.content.Context;
-import android.graphics.drawable.Drawable;
-import android.os.Bundle;
-import android.preference.PreferenceFragment;
-
-/**
- * This is a helper class for an IME's settings preference fragment. It's recommended for every
- * IME to have its own settings preference fragment which inherits this class.
- */
-public abstract class InputMethodSettingsFragment extends PreferenceFragment
-        implements InputMethodSettingsInterface {
-    private final InputMethodSettingsImpl mSettings = new InputMethodSettingsImpl();
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        final Context context = getActivity();
-        setPreferenceScreen(getPreferenceManager().createPreferenceScreen(context));
-        mSettings.init(context, getPreferenceScreen());
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setInputMethodSettingsCategoryTitle(int resId) {
-        mSettings.setInputMethodSettingsCategoryTitle(resId);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setInputMethodSettingsCategoryTitle(CharSequence title) {
-        mSettings.setInputMethodSettingsCategoryTitle(title);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerTitle(int resId) {
-        mSettings.setSubtypeEnablerTitle(resId);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerTitle(CharSequence title) {
-        mSettings.setSubtypeEnablerTitle(title);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerIcon(int resId) {
-        mSettings.setSubtypeEnablerIcon(resId);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerIcon(Drawable drawable) {
-        mSettings.setSubtypeEnablerIcon(drawable);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void onResume() {
-        super.onResume();
-        mSettings.updateSubtypeEnabler();
-    }
-}

app/src/main/java/org/dslul/openboard/inputmethodcommon/InputMethodSettingsFragment.kt

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.dslul.openboard.inputmethodcommon
+
+import android.content.Context
+import android.graphics.drawable.Drawable
+import android.os.Bundle
+import android.preference.PreferenceFragment
+
+/**
+ * This is a helper class for an IME's settings preference fragment. It's recommended for every
+ * IME to have its own settings preference fragment which inherits this class.
+ */
+abstract class InputMethodSettingsFragment : PreferenceFragment(), InputMethodSettingsInterface {
+    private val mSettings = InputMethodSettingsImpl()
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val context: Context = activity
+        preferenceScreen = preferenceManager.createPreferenceScreen(context)
+        mSettings.init(context, preferenceScreen)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setInputMethodSettingsCategoryTitle(resId: Int) {
+        mSettings.setInputMethodSettingsCategoryTitle(resId)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setInputMethodSettingsCategoryTitle(title: CharSequence?) {
+        mSettings.setInputMethodSettingsCategoryTitle(title)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerTitle(resId: Int) {
+        mSettings.setSubtypeEnablerTitle(resId)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerTitle(title: CharSequence?) {
+        mSettings.setSubtypeEnablerTitle(title)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerIcon(resId: Int) {
+        mSettings.setSubtypeEnablerIcon(resId)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerIcon(drawable: Drawable?) {
+        mSettings.setSubtypeEnablerIcon(drawable)
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun onResume() {
+        super.onResume()
+        mSettings.updateSubtypeEnabler()
+    }
+}

app/src/main/java/org/dslul/openboard/inputmethodcommon/InputMethodSettingsImpl.java

@@ -1,179 +0,0 @@
-/*
- * Copyright (C) 2011 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.dslul.openboard.inputmethodcommon;
-
-import android.content.Context;
-import android.content.Intent;
-import android.graphics.drawable.Drawable;
-import android.preference.Preference;
-import android.preference.Preference.OnPreferenceClickListener;
-import android.preference.PreferenceScreen;
-import android.provider.Settings;
-import android.text.TextUtils;
-import android.view.inputmethod.InputMethodInfo;
-import android.view.inputmethod.InputMethodManager;
-import android.view.inputmethod.InputMethodSubtype;
-
-import java.util.List;
-
-/* package private */ class InputMethodSettingsImpl implements InputMethodSettingsInterface {
-    private Preference mSubtypeEnablerPreference;
-    private int mInputMethodSettingsCategoryTitleRes;
-    private CharSequence mInputMethodSettingsCategoryTitle;
-    private int mSubtypeEnablerTitleRes;
-    private CharSequence mSubtypeEnablerTitle;
-    private int mSubtypeEnablerIconRes;
-    private Drawable mSubtypeEnablerIcon;
-    private InputMethodManager mImm;
-    private InputMethodInfo mImi;
-
-    /**
-     * Initialize internal states of this object.
-     * @param context the context for this application.
-     * @param prefScreen a PreferenceScreen of PreferenceActivity or PreferenceFragment.
-     * @return true if this application is an IME and has two or more subtypes, false otherwise.
-     */
-    public boolean init(final Context context, final PreferenceScreen prefScreen) {
-        mImm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
-        mImi = getMyImi(context, mImm);
-        if (mImi == null || mImi.getSubtypeCount() <= 1) {
-            return false;
-        }
-        final Intent intent = new Intent(Settings.ACTION_INPUT_METHOD_SUBTYPE_SETTINGS);
-        intent.putExtra(Settings.EXTRA_INPUT_METHOD_ID, mImi.getId());
-        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
-                | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
-                | Intent.FLAG_ACTIVITY_CLEAR_TOP);
-        mSubtypeEnablerPreference = new Preference(context);
-        mSubtypeEnablerPreference.setIntent(intent);
-        prefScreen.addPreference(mSubtypeEnablerPreference);
-        updateSubtypeEnabler();
-        return true;
-    }
-
-    private static InputMethodInfo getMyImi(Context context, InputMethodManager imm) {
-        final List<InputMethodInfo> imis = imm.getInputMethodList();
-        for (int i = 0; i < imis.size(); ++i) {
-            final InputMethodInfo imi = imis.get(i);
-            if (imis.get(i).getPackageName().equals(context.getPackageName())) {
-                return imi;
-            }
-        }
-        return null;
-    }
-
-    private static String getEnabledSubtypesLabel(
-            Context context, InputMethodManager imm, InputMethodInfo imi) {
-        if (context == null || imm == null || imi == null) return null;
-        final List<InputMethodSubtype> subtypes = imm.getEnabledInputMethodSubtypeList(imi, true);
-        final StringBuilder sb = new StringBuilder();
-        final int N = subtypes.size();
-        for (int i = 0; i < N; ++i) {
-            final InputMethodSubtype subtype = subtypes.get(i);
-            if (sb.length() > 0) {
-                sb.append(", ");
-            }
-            sb.append(subtype.getDisplayName(context, imi.getPackageName(),
-                    imi.getServiceInfo().applicationInfo));
-        }
-        return sb.toString();
-    }
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setInputMethodSettingsCategoryTitle(int resId) {
-        mInputMethodSettingsCategoryTitleRes = resId;
-        updateSubtypeEnabler();
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setInputMethodSettingsCategoryTitle(CharSequence title) {
-        mInputMethodSettingsCategoryTitleRes = 0;
-        mInputMethodSettingsCategoryTitle = title;
-        updateSubtypeEnabler();
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerTitle(int resId) {
-        mSubtypeEnablerTitleRes = resId;
-        updateSubtypeEnabler();
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerTitle(CharSequence title) {
-        mSubtypeEnablerTitleRes = 0;
-        mSubtypeEnablerTitle = title;
-        updateSubtypeEnabler();
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerIcon(int resId) {
-        mSubtypeEnablerIconRes = resId;
-        updateSubtypeEnabler();
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public void setSubtypeEnablerIcon(Drawable drawable) {
-        mSubtypeEnablerIconRes = 0;
-        mSubtypeEnablerIcon = drawable;
-        updateSubtypeEnabler();
-    }
-
-    public void updateSubtypeEnabler() {
-        final Preference pref = mSubtypeEnablerPreference;
-        if (pref == null) {
-            return;
-        }
-        final Context context = pref.getContext();
-        final CharSequence title;
-        if (mSubtypeEnablerTitleRes != 0) {
-            title = context.getString(mSubtypeEnablerTitleRes);
-        } else {
-            title = mSubtypeEnablerTitle;
-        }
-        pref.setTitle(title);
-        final Intent intent = pref.getIntent();
-        if (intent != null) {
-            intent.putExtra(Intent.EXTRA_TITLE, title);
-        }
-        final String summary = getEnabledSubtypesLabel(context, mImm, mImi);
-        if (!TextUtils.isEmpty(summary)) {
-            pref.setSummary(summary);
-        }
-        if (mSubtypeEnablerIconRes != 0) {
-            pref.setIcon(mSubtypeEnablerIconRes);
-        } else {
-            pref.setIcon(mSubtypeEnablerIcon);
-        }
-    }
-}

app/src/main/java/org/dslul/openboard/inputmethodcommon/InputMethodSettingsImpl.kt

@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.dslul.openboard.inputmethodcommon
+
+import android.content.Context
+import android.content.Intent
+import android.graphics.drawable.Drawable
+import android.preference.Preference
+import android.preference.PreferenceScreen
+import android.provider.Settings
+import android.text.TextUtils
+import android.view.inputmethod.InputMethodInfo
+import android.view.inputmethod.InputMethodManager
+
+/* package private */
+internal class InputMethodSettingsImpl : InputMethodSettingsInterface {
+    private var mSubtypeEnablerPreference: Preference? = null
+    private var mInputMethodSettingsCategoryTitleRes = 0
+    private var mInputMethodSettingsCategoryTitle: CharSequence? = null
+    private var mSubtypeEnablerTitleRes = 0
+    private var mSubtypeEnablerTitle: CharSequence? = null
+    private var mSubtypeEnablerIconRes = 0
+    private var mSubtypeEnablerIcon: Drawable? = null
+    private var mImm: InputMethodManager? = null
+    private var mImi: InputMethodInfo? = null
+    /**
+     * Initialize internal states of this object.
+     * @param context the context for this application.
+     * @param prefScreen a PreferenceScreen of PreferenceActivity or PreferenceFragment.
+     * @return true if this application is an IME and has two or more subtypes, false otherwise.
+     */
+    fun init(context: Context, prefScreen: PreferenceScreen): Boolean {
+        mImm = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
+        mImi = getMyImi(context, mImm)
+        if (mImi == null || mImi!!.subtypeCount <= 1) {
+            return false
+        }
+        val intent = Intent(Settings.ACTION_INPUT_METHOD_SUBTYPE_SETTINGS)
+        intent.putExtra(Settings.EXTRA_INPUT_METHOD_ID, mImi!!.id)
+        intent.flags = (Intent.FLAG_ACTIVITY_NEW_TASK
+                or Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
+                or Intent.FLAG_ACTIVITY_CLEAR_TOP)
+        mSubtypeEnablerPreference = Preference(context)
+        mSubtypeEnablerPreference!!.intent = intent
+        prefScreen.addPreference(mSubtypeEnablerPreference)
+        updateSubtypeEnabler()
+        return true
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setInputMethodSettingsCategoryTitle(resId: Int) {
+        mInputMethodSettingsCategoryTitleRes = resId
+        updateSubtypeEnabler()
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setInputMethodSettingsCategoryTitle(title: CharSequence?) {
+        mInputMethodSettingsCategoryTitleRes = 0
+        mInputMethodSettingsCategoryTitle = title
+        updateSubtypeEnabler()
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerTitle(resId: Int) {
+        mSubtypeEnablerTitleRes = resId
+        updateSubtypeEnabler()
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerTitle(title: CharSequence?) {
+        mSubtypeEnablerTitleRes = 0
+        mSubtypeEnablerTitle = title
+        updateSubtypeEnabler()
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerIcon(resId: Int) {
+        mSubtypeEnablerIconRes = resId
+        updateSubtypeEnabler()
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    override fun setSubtypeEnablerIcon(drawable: Drawable?) {
+        mSubtypeEnablerIconRes = 0
+        mSubtypeEnablerIcon = drawable
+        updateSubtypeEnabler()
+    }
+
+    fun updateSubtypeEnabler() {
+        val pref = mSubtypeEnablerPreference ?: return
+        val context = pref.context
+        val title: CharSequence?
+        title = if (mSubtypeEnablerTitleRes != 0) {
+            context.getString(mSubtypeEnablerTitleRes)
+        } else {
+            mSubtypeEnablerTitle
+        }
+        pref.title = title
+        val intent = pref.intent
+        intent?.putExtra(Intent.EXTRA_TITLE, title)
+        val summary = getEnabledSubtypesLabel(context, mImm, mImi)
+        if (!TextUtils.isEmpty(summary)) {
+            pref.summary = summary
+        }
+        if (mSubtypeEnablerIconRes != 0) {
+            pref.setIcon(mSubtypeEnablerIconRes)
+        } else {
+            pref.icon = mSubtypeEnablerIcon
+        }
+    }
+
+    companion object {
+        private fun getMyImi(context: Context, imm: InputMethodManager?): InputMethodInfo? {
+            val imis = imm!!.inputMethodList
+            for (i in imis.indices) {
+                val imi = imis[i]
+                if (imis[i].packageName == context.packageName) {
+                    return imi
+                }
+            }
+            return null
+        }
+
+        private fun getEnabledSubtypesLabel(
+                context: Context?, imm: InputMethodManager?, imi: InputMethodInfo?): String? {
+            if (context == null || imm == null || imi == null) return null
+            val subtypes = imm.getEnabledInputMethodSubtypeList(imi, true)
+            val sb = StringBuilder()
+            val N = subtypes.size
+            for (i in 0 until N) {
+                val subtype = subtypes[i]
+                if (sb.length > 0) {
+                    sb.append(", ")
+                }
+                sb.append(subtype.getDisplayName(context, imi.packageName,
+                        imi.serviceInfo.applicationInfo))
+            }
+            return sb.toString()
+        }
+    }
+}

app/src/main/java/org/dslul/openboard/inputmethodcommon/InputMethodSettingsInterface.kt

@@ -13,51 +13,50 @@
  * See the License for the specific language governing permissions and
  * limitations under the License
  */
+package org.dslul.openboard.inputmethodcommon
 
-package org.dslul.openboard.inputmethodcommon;
-
-import android.graphics.drawable.Drawable;
+import android.graphics.drawable.Drawable
 
 /**
  * InputMethodSettingsInterface is the interface for adding IME related preferences to
  * PreferenceActivity or PreferenceFragment.
  */
-public interface InputMethodSettingsInterface {
+interface InputMethodSettingsInterface {
     /**
      * Sets the title for the input method settings category with a resource ID.
      * @param resId The resource ID of the title.
      */
-    public void setInputMethodSettingsCategoryTitle(int resId);
+    fun setInputMethodSettingsCategoryTitle(resId: Int)
 
     /**
      * Sets the title for the input method settings category with a CharSequence.
      * @param title The title for this preference.
      */
-    public void setInputMethodSettingsCategoryTitle(CharSequence title);
+    fun setInputMethodSettingsCategoryTitle(title: CharSequence?)
 
     /**
      * Sets the title for the input method enabler preference for launching subtype enabler with a
      * resource ID.
      * @param resId The resource ID of the title.
      */
-    public void setSubtypeEnablerTitle(int resId);
+    fun setSubtypeEnablerTitle(resId: Int)
 
     /**
      * Sets the title for the input method enabler preference for launching subtype enabler with a
      * CharSequence.
      * @param title The title for this preference.
      */
-    public void setSubtypeEnablerTitle(CharSequence title);
+    fun setSubtypeEnablerTitle(title: CharSequence?)
 
     /**
      * Sets the icon for the preference for launching subtype enabler with a resource ID.
      * @param resId The resource id of an optional icon for the preference.
      */
-    public void setSubtypeEnablerIcon(int resId);
+    fun setSubtypeEnablerIcon(resId: Int)
 
     /**
      * Sets the icon for the Preference for launching subtype enabler with a Drawable.
      * @param drawable The drawable of an optional icon for the preference.
      */
-    public void setSubtypeEnablerIcon(Drawable drawable);
-}
+    fun setSubtypeEnablerIcon(drawable: Drawable?)
+}

build.gradle

@@ -1,12 +1,14 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
+    ext.kotlin_version = '1.3.61'
     repositories {
         jcenter()
         google()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.5.3'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files