Add display settings dashboard to new IA.

- Added a activity-alias pointing to displaySettings as top level
  setting item.
- Refactored all preference logic in DisplaySettings into
  PreferenceControllers. During fragment onAttach it installs all
  controllers, and during onResume it updates preference state. Each
  controller listens to its own preference change event.

Bug: 31800242
Test: RunSettingsRoboTests
Change-Id: Ibc9bf200c5acce7c4ae9292340822afee27a3a28

src/com/android/settings/dashboard/DashboardFragment.java

@@ -55,6 +55,14 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         super.onAttach(context);
         mDashboardFeatureProvider =
                 FeatureFactory.getFactory(context).getDashboardFeatureProvider(context);
+
+        final List<PreferenceController> controllers = getPreferenceControllers(context);
+        if (controllers == null) {
+            return;
+        }
+        for (PreferenceController controller : controllers) {
+            addPreferenceController(controller);
+        }
     }
 
     @Override
@@ -81,7 +89,10 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         if (category == null) {
             return;
         }
-        mSummaryLoader.setListening(true);
+        if (mSummaryLoader != null) {
+            // SummaryLoader can be null when there is no dynamic tiles.
+            mSummaryLoader.setListening(true);
+        }
         final Activity activity = getActivity();
         if (activity instanceof SettingsDrawerActivity) {
             mListeningToCategoryChange = true;
@@ -102,6 +113,12 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         pref.setSummary(tile.summary);
     }
 
+    @Override
+    public void onResume() {
+        super.onResume();
+        updatePreferenceStates();
+    }
+
     @Override
     public boolean onPreferenceTreeClick(Preference preference) {
         Collection<PreferenceController> controllers = mPreferenceControllers.values();
@@ -117,7 +134,10 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
     @Override
     public void onStop() {
         super.onStop();
-        mSummaryLoader.setListening(false);
+        if (mSummaryLoader != null) {
+            // SummaryLoader can be null when there is no dynamic tiles.
+            mSummaryLoader.setListening(false);
+        }
         if (mListeningToCategoryChange) {
             final Activity activity = getActivity();
             if (activity instanceof SettingsDrawerActivity) {
@@ -141,12 +161,36 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
      */
     protected abstract String getCategoryKey();
 
+    /**
+     * Get the tag string for logging.
+     */
+    protected abstract String getLogTag();
+
+    /**
+     * Get the res id for static preference xml for this fragment.
+     */
+    protected abstract int getPreferenceScreenResId();
+
+    /**
+     * Get a list of {@link PreferenceController} for this fragment.
+     */
+    protected abstract List<PreferenceController> getPreferenceControllers(Context context);
+
     /**
      * Displays resource based tiles.
      */
-    protected abstract void displayResourceTiles();
-
-    protected abstract String getLogTag();
+    private void displayResourceTiles() {
+        final int resId = getPreferenceScreenResId();
+        if (resId <= 0) {
+            return;
+        }
+        addPreferencesFromResource(resId);
+        final PreferenceScreen screen = getPreferenceScreen();
+        Collection<PreferenceController> controllers = mPreferenceControllers.values();
+        for (PreferenceController controller : controllers) {
+            controller.displayPreference(screen);
+        }
+    }
 
     /**
      * Displays dashboard tiles as preference.
@@ -195,6 +239,17 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         }
     }
 
+    /**
+     * Update state of each preference managed by PreferenceController.
+     */
+    private void updatePreferenceStates() {
+        Collection<PreferenceController> controllers = mPreferenceControllers.values();
+        final PreferenceScreen screen = getPreferenceScreen();
+        for (PreferenceController controller : controllers) {
+            controller.updateState(screen);
+        }
+    }
+
     /**
      * Refresh preference items using system category dashboard items.
      */
@@ -206,6 +261,7 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         }
         // Add resource based tiles.
         displayResourceTiles();
+
         // Add dashboard tiles.
         displayDashboardTiles(TAG, getPreferenceScreen());
     }