Refactor CaptionMoreOptionsFragment to improve maintainability

Root cause: There is a bunch of different logic of preferences in CaptionMoreOptionsFragment. It’s hard to implement new features and hard to maintain and hard to be testable.
Solution: Move out different logic of CaptionMoreOptionsFragment into controllers to reduce the complexity of the relationship between preference and fragment.

Bug: 197695932
Test: make RunSettingsRoboTests ROBOTEST_FILTER=CaptionMoreOptionsFragmentTest CaptionLocalePreferenceControllerTest
Change-Id: Ifdf3e22b027328a9f8eb13d756730ca047ece047

res/xml/captioning_more_options.xml

@@ -22,8 +22,8 @@
 
     <com.android.settings.accessibility.LocalePreference
         android:key="captioning_locale"
-        android:summary="%s"
-        android:title="@string/captioning_locale" />
+        android:title="@string/captioning_locale"
+        settings:controller="com.android.settings.accessibility.CaptionLocalePreferenceController"/>
 
     <com.android.settings.accessibility.AccessibilityFooterPreference
         android:key="captioning_more_options_footer"

src/com/android/settings/accessibility/CaptionLocalePreferenceController.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2022 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 com.android.settings.accessibility;
+
+import android.content.Context;
+import android.provider.Settings;
+import android.view.accessibility.CaptioningManager;
+
+import androidx.preference.Preference;
+import androidx.preference.PreferenceScreen;
+
+import com.android.settings.core.BasePreferenceController;
+
+/** Controller that shows the caption locale summary. */
+public class CaptionLocalePreferenceController extends BasePreferenceController
+        implements Preference.OnPreferenceChangeListener {
+
+    private final CaptioningManager mCaptioningManager;
+    private LocalePreference mPreference;
+
+    public CaptionLocalePreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+        mCaptioningManager = context.getSystemService(CaptioningManager.class);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = screen.findPreference(getPreferenceKey());
+        final String rawLocale = mCaptioningManager.getRawLocale();
+        mPreference.setValue(rawLocale == null ? "" : rawLocale);
+    }
+
+    @Override
+    public CharSequence getSummary() {
+        return mPreference.getEntry();
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        Settings.Secure.putString(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_LOCALE, (String) newValue);
+        mPreference.setValue((String) newValue);
+        mPreference.setSummary(mPreference.getEntry());
+        return true;
+    }
+}

src/com/android/settings/accessibility/CaptionMoreOptionsFragment.java

@@ -17,13 +17,6 @@
 package com.android.settings.accessibility;
 
 import android.app.settings.SettingsEnums;
-import android.content.ContentResolver;
-import android.content.Context;
-import android.os.Bundle;
-import android.provider.Settings;
-import android.view.accessibility.CaptioningManager;
-
-import androidx.preference.Preference;
 
 import com.android.settings.R;
 import com.android.settings.dashboard.DashboardFragment;
@@ -32,31 +25,15 @@ import com.android.settingslib.search.SearchIndexable;
 
 /** Settings fragment containing more options of captioning properties. */
 @SearchIndexable(forTarget = SearchIndexable.ALL & ~SearchIndexable.ARC)
-public class CaptionMoreOptionsFragment extends DashboardFragment
-        implements Preference.OnPreferenceChangeListener {
+public class CaptionMoreOptionsFragment extends DashboardFragment {
 
     private static final String TAG = "CaptionMoreOptionsFragment";
-    private static final String PREF_LOCALE = "captioning_locale";
-
-    private CaptioningManager mCaptioningManager;
-    private LocalePreference mLocale;
 
     @Override
     public int getMetricsCategory() {
         return SettingsEnums.ACCESSIBILITY_CAPTION_MORE_OPTIONS;
     }
 
-    @Override
-    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
-        super.onCreatePreferences(savedInstanceState, rootKey);
-
-        mCaptioningManager = (CaptioningManager) getSystemService(Context.CAPTIONING_SERVICE);
-
-        initializeAllPreferences();
-        updateAllPreferences();
-        installUpdateListeners();
-    }
-
     @Override
     protected int getPreferenceScreenResId() {
         return R.xml.captioning_more_options;
@@ -67,30 +44,6 @@ public class CaptionMoreOptionsFragment extends DashboardFragment
         return TAG;
     }
 
-    private void initializeAllPreferences() {
-        mLocale = (LocalePreference) findPreference(PREF_LOCALE);
-    }
-
-    private void installUpdateListeners() {
-        mLocale.setOnPreferenceChangeListener(this);
-    }
-
-    private void updateAllPreferences() {
-        final String rawLocale = mCaptioningManager.getRawLocale();
-        mLocale.setValue(rawLocale == null ? "" : rawLocale);
-    }
-
-    @Override
-    public boolean onPreferenceChange(Preference preference, Object value) {
-        final ContentResolver cr = getActivity().getContentResolver();
-        if (mLocale == preference) {
-            Settings.Secure.putString(
-                    cr, Settings.Secure.ACCESSIBILITY_CAPTIONING_LOCALE, (String) value);
-        }
-
-        return true;
-    }
-
     @Override
     public int getHelpResource() {
         return R.string.help_url_caption;

tests/robotests/src/com/android/settings/accessibility/CaptionLocalePreferenceControllerTest.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2022 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 com.android.settings.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import androidx.preference.PreferenceScreen;
+import androidx.test.core.app.ApplicationProvider;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+import org.robolectric.RobolectricTestRunner;
+
+/** Tests for {@link CaptionLocalePreferenceController}. */
+@RunWith(RobolectricTestRunner.class)
+public class CaptionLocalePreferenceControllerTest {
+
+    @Rule
+    public final MockitoRule mMockitoRule = MockitoJUnit.rule();
+    @Mock
+    private PreferenceScreen mScreen;
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+    private CaptionLocalePreferenceController mController;
+    private LocalePreference mPreference;
+
+    @Before
+    public void setUp() {
+        mController = new CaptionLocalePreferenceController(mContext, "captioning_local_pref");
+        mPreference = new LocalePreference(mContext);
+        when(mScreen.findPreference(mController.getPreferenceKey())).thenReturn(mPreference);
+    }
+
+    @Test
+    public void getAvailabilityStatus_shouldReturnAvailable() {
+        assertThat(mController.getAvailabilityStatus())
+                .isEqualTo(BasePreferenceController.AVAILABLE);
+    }
+
+    @Test
+    public void getSummary_byDefault_shouldReturnDefault() {
+        mController.displayPreference(mScreen);
+
+        assertThat(mController.getSummary().toString()).isEqualTo(
+                mContext.getResources().getString(R.string.locale_default));
+    }
+
+    @Test
+    public void getSummary_byArabicLocale_shouldReturnArabic() {
+        Settings.Secure.putString(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_CAPTIONING_LOCALE, "af_ZA");
+
+        mController.displayPreference(mScreen);
+
+        assertThat(mController.getSummary().toString()).isEqualTo("Afrikaans");
+    }
+
+    @Test
+    public void onPreferenceChange_byArabicLocale_shouldReturnArabic() {
+        mController.displayPreference(mScreen);
+
+        mController.onPreferenceChange(mPreference, "af_ZA");
+
+        assertThat(mPreference.getSummary().toString()).isEqualTo("Afrikaans");
+    }
+}

tests/robotests/src/com/android/settings/accessibility/CaptionMoreOptionsFragmentTest.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2022 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 com.android.settings.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+
+import androidx.test.core.app.ApplicationProvider;
+
+import com.android.settings.R;
+import com.android.settings.testutils.XmlTestUtils;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+import java.util.List;
+
+/** Tests for {@link CaptionMoreOptionsFragment}. */
+@RunWith(RobolectricTestRunner.class)
+public class CaptionMoreOptionsFragmentTest {
+
+    private Context mContext = ApplicationProvider.getApplicationContext();
+
+    @Test
+    public void getNonIndexableKeys_existInXmlLayout() {
+        final List<String> niks = CaptionMoreOptionsFragment.SEARCH_INDEX_DATA_PROVIDER
+                .getNonIndexableKeys(mContext);
+        final List<String> keys =
+                XmlTestUtils.getKeysFromPreferenceXml(mContext,
+                        R.xml.captioning_more_options);
+
+        assertThat(keys).containsAtLeastElementsIn(niks);
+    }
+}