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

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;
+    }
+}