Merge "Refactor SettingsContentObserver and add it to follow typing feature."

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

@@ -30,7 +30,6 @@ import android.content.pm.ResolveInfo;
 import android.content.pm.ServiceInfo;
 import android.graphics.Color;
 import android.graphics.drawable.Drawable;
-import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.UserHandle;
@@ -147,7 +146,7 @@ public class AccessibilitySettings extends DashboardFragment {
     };
 
     @VisibleForTesting
-    final SettingsContentObserver mSettingsContentObserver;
+    final AccessibilitySettingsContentObserver mSettingsContentObserver;
 
     private final Map<String, PreferenceCategory> mCategoryToPrefCategoryMap =
             new ArrayMap<>();
@@ -171,12 +170,9 @@ public class AccessibilitySettings extends DashboardFragment {
         // Observe changes from accessibility selection menu
         shortcutFeatureKeys.add(Settings.Secure.ACCESSIBILITY_BUTTON_TARGETS);
         shortcutFeatureKeys.add(Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE);
-        mSettingsContentObserver = new SettingsContentObserver(mHandler, shortcutFeatureKeys) {
+        mSettingsContentObserver = new AccessibilitySettingsContentObserver(mHandler);
-            @Override
+        mSettingsContentObserver.registerKeysToObserverCallback(shortcutFeatureKeys,
-            public void onChange(boolean selfChange, Uri uri) {
+                key -> onContentChanged());
-                onContentChanged();
-            }
-        };
     }
 
     @Override

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

@@ -0,0 +1,132 @@
+/*
+ * 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.ContentResolver;
+import android.database.ContentObserver;
+import android.net.Uri;
+import android.os.Handler;
+import android.provider.Settings;
+import android.util.Log;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+class AccessibilitySettingsContentObserver extends ContentObserver {
+
+    private static final String TAG = "AccessibilitySettingsContentObserver";
+
+    public interface ContentObserverCallback {
+        void onChange(String key);
+    }
+
+    // Key: Preference key's uri, Value: Preference key
+    private final Map<Uri, String> mUriToKey = new HashMap<>(2);
+
+    // Key: Collection of preference keys, Value: onChange callback for keys
+    private final Map<List<String>, ContentObserverCallback> mUrisToCallback = new HashMap<>();
+
+    AccessibilitySettingsContentObserver(Handler handler) {
+        super(handler);
+
+        // default key to be observed
+        addDefaultKeysToMap();
+    }
+
+    public void register(ContentResolver contentResolver) {
+        for (Uri uri : mUriToKey.keySet()) {
+            contentResolver.registerContentObserver(uri, false, this);
+        }
+    }
+
+    public void unregister(ContentResolver contentResolver) {
+        contentResolver.unregisterContentObserver(this);
+    }
+
+    private void addDefaultKeysToMap() {
+        addKeyToMap(Settings.Secure.ACCESSIBILITY_ENABLED);
+        addKeyToMap(Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES);
+    }
+
+    private boolean isDefaultKey(String key) {
+        return Settings.Secure.ACCESSIBILITY_ENABLED.equals(key)
+                || Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES.equals(key);
+    }
+
+    private void addKeyToMap(String key) {
+        mUriToKey.put(Settings.Secure.getUriFor(key), key);
+    }
+
+    /**
+     * {@link ContentObserverCallback} is added to {@link ContentObserver} to handle the
+     * onChange event triggered by the key collection of {@code keysToObserve} and the default
+     * keys.
+     *
+     * Note: The following key are default to be observed.
+     *      {@link Settings.Secure.ACCESSIBILITY_ENABLED}
+     *      {@link Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES}
+     *
+     * @param keysToObserve A collection of keys which are going to be observed.
+     * @param observerCallback A callback which is used to handle the onChange event triggered
+     *                         by the key collection of {@code keysToObserve}.
+     */
+    public void registerKeysToObserverCallback(List<String> keysToObserve,
+            ContentObserverCallback observerCallback) {
+
+        for (String key: keysToObserve) {
+            addKeyToMap(key);
+        }
+
+        mUrisToCallback.put(keysToObserve, observerCallback);
+    }
+
+    /**
+     * {@link ContentObserverCallback} is added to {@link ContentObserver} to handle the
+     * onChange event triggered by the default keys.
+     *
+     * Note: The following key are default to be observed.
+     *      {@link Settings.Secure.ACCESSIBILITY_ENABLED}
+     *      {@link Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES}
+     *
+     * @param observerCallback A callback which is used to handle the onChange event triggered
+     *      *                         by the key collection of {@code keysToObserve}.
+     */
+    public void registerObserverCallback(ContentObserverCallback observerCallback) {
+        mUrisToCallback.put(Collections.emptyList(), observerCallback);
+    }
+
+    @Override
+    public final void onChange(boolean selfChange, Uri uri) {
+
+        final String key = mUriToKey.get(uri);
+
+        if (key == null) {
+            Log.w(TAG, "AccessibilitySettingsContentObserver can not find the key for "
+                    + "uri: " + uri);
+            return;
+        }
+
+        for (List<String> keys : mUrisToCallback.keySet()) {
+            final boolean isDefaultKey = isDefaultKey(key);
+            if (isDefaultKey || keys.contains(key)) {
+                mUrisToCallback.get(keys).onChange(key);
+            }
+        }
+    }
+}

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

@@ -25,7 +25,6 @@ import android.content.ComponentName;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.icu.text.CaseMap;
-import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
 import android.provider.Settings;
@@ -64,7 +63,7 @@ public abstract class AccessibilityShortcutPreferenceFragment extends DashboardF
     protected ShortcutPreference mShortcutPreference;
     private AccessibilityManager.TouchExplorationStateChangeListener
             mTouchExplorationStateChangeListener;
-    private SettingsContentObserver mSettingsContentObserver;
+    private AccessibilitySettingsContentObserver mSettingsContentObserver;
     private CheckBox mSoftwareTypeCheckBox;
     private CheckBox mHardwareTypeCheckBox;
 
@@ -98,13 +97,11 @@ public abstract class AccessibilityShortcutPreferenceFragment extends DashboardF
         final List<String> shortcutFeatureKeys = new ArrayList<>();
         shortcutFeatureKeys.add(Settings.Secure.ACCESSIBILITY_BUTTON_TARGETS);
         shortcutFeatureKeys.add(Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE);
-        mSettingsContentObserver = new SettingsContentObserver(new Handler(), shortcutFeatureKeys) {
+        mSettingsContentObserver = new AccessibilitySettingsContentObserver(new Handler());
-            @Override
+        mSettingsContentObserver.registerKeysToObserverCallback(shortcutFeatureKeys, key -> {
-            public void onChange(boolean selfChange, Uri uri) {
+            updateShortcutPreferenceData();
-                updateShortcutPreferenceData();
+            updateShortcutPreference();
-                updateShortcutPreference();
+        });
-            }
-        };
     }
 
     @Override

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

@@ -35,6 +35,8 @@ import com.android.settings.core.TogglePreferenceController;
 public class MagnificationFollowTypingPreferenceController extends TogglePreferenceController
         implements LifecycleObserver {
 
+    private static final String TAG =
+            MagnificationFollowTypingPreferenceController.class.getSimpleName();
     static final String PREF_KEY = "magnification_follow_typing";
 
     private SwitchPreference mFollowTypingPreference;
@@ -75,6 +77,14 @@ public class MagnificationFollowTypingPreferenceController extends TogglePrefere
     // TODO(b/186731461): Remove it when this controller is used in DashBoardFragment only.
     @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
     void onResume() {
+        updateState();
+    }
+
+    /**
+     * Updates the state of preference components which has been displayed by
+     * {@link MagnificationFollowTypingPreferenceController#displayPreference}.
+     */
+    void updateState() {
         updateState(mFollowTypingPreference);
     }
 }

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

@@ -1,55 +0,0 @@
-/*
- * Copyright (C) 2013 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.ContentResolver;
-import android.database.ContentObserver;
-import android.net.Uri;
-import android.os.Handler;
-import android.provider.Settings;
-
-import java.util.ArrayList;
-import java.util.List;
-
-abstract class SettingsContentObserver extends ContentObserver {
-    private final List<String> mKeysToObserve = new ArrayList<>(2);
-
-    public SettingsContentObserver(Handler handler) {
-        super(handler);
-        mKeysToObserve.add(Settings.Secure.ACCESSIBILITY_ENABLED);
-        mKeysToObserve.add(Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES);
-    }
-
-    public SettingsContentObserver(Handler handler, List<String> keysToObserve) {
-        this(handler);
-        mKeysToObserve.addAll(keysToObserve);
-    }
-
-    public void register(ContentResolver contentResolver) {
-        for (int i = 0; i < mKeysToObserve.size(); i++) {
-            contentResolver.registerContentObserver(
-                    Settings.Secure.getUriFor(mKeysToObserve.get(i)), false, this);
-        }
-    }
-
-    public void unregister(ContentResolver contentResolver) {
-        contentResolver.unregisterContentObserver(this);
-    }
-
-    @Override
-    public abstract void onChange(boolean selfChange, Uri uri);
-}

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

@@ -35,7 +35,6 @@ import android.content.pm.ResolveInfo;
 import android.content.pm.ServiceInfo;
 import android.net.Uri;
 import android.os.Bundle;
-import android.os.Handler;
 import android.os.SystemClock;
 import android.text.TextUtils;
 import android.util.Log;
@@ -65,15 +64,7 @@ public class ToggleAccessibilityServicePreferenceFragment extends
 
     private static final String EMPTY_STRING = "";
 
-    private final SettingsContentObserver mSettingsContentObserver =
+    private Dialog mWarningDialog;
-            new SettingsContentObserver(new Handler()) {
-                @Override
-                public void onChange(boolean selfChange, Uri uri) {
-                    updateSwitchBarToggleSwitch();
-                }
-            };
-
-    private Dialog mDialog;
     private BroadcastReceiver mPackageRemovedReceiver;
     private boolean mDisabledStateLogged = false;
     private long mStartTimeMillsForLogging = 0;
@@ -108,6 +99,13 @@ public class ToggleAccessibilityServicePreferenceFragment extends
         }
     }
 
+    @Override
+    protected void registerKeysToObserverCallback(
+            AccessibilitySettingsContentObserver contentObserver) {
+        super.registerKeysToObserverCallback(contentObserver);
+        contentObserver.registerObserverCallback(key -> updateSwitchBarToggleSwitch());
+    }
+
     @Override
     public void onStart() {
         super.onStart();
@@ -123,7 +121,11 @@ public class ToggleAccessibilityServicePreferenceFragment extends
     public void onResume() {
         super.onResume();
         updateSwitchBarToggleSwitch();
-        mSettingsContentObserver.register(getContentResolver());
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
     }
 
     @Override
@@ -172,7 +174,7 @@ public class ToggleAccessibilityServicePreferenceFragment extends
                 if (info == null) {
                     return null;
                 }
-                mDialog = AccessibilityServiceWarning
+                mWarningDialog = AccessibilityServiceWarning
                         .createCapabilitiesDialog(getPrefContext(), info,
                                 this::onDialogButtonFromEnableToggleClicked,
                                 this::onDialogButtonFromUninstallClicked);
@@ -183,7 +185,7 @@ public class ToggleAccessibilityServicePreferenceFragment extends
                 if (info == null) {
                     return null;
                 }
-                mDialog = AccessibilityServiceWarning
+                mWarningDialog = AccessibilityServiceWarning
                         .createCapabilitiesDialog(getPrefContext(), info,
                                 this::onDialogButtonFromShortcutToggleClicked,
                                 this::onDialogButtonFromUninstallClicked);
@@ -194,7 +196,7 @@ public class ToggleAccessibilityServicePreferenceFragment extends
                 if (info == null) {
                     return null;
                 }
-                mDialog = AccessibilityServiceWarning
+                mWarningDialog = AccessibilityServiceWarning
                         .createCapabilitiesDialog(getPrefContext(), info,
                                 this::onDialogButtonFromShortcutClicked,
                                 this::onDialogButtonFromUninstallClicked);
@@ -205,16 +207,16 @@ public class ToggleAccessibilityServicePreferenceFragment extends
                 if (info == null) {
                     return null;
                 }
-                mDialog = AccessibilityServiceWarning
+                mWarningDialog = AccessibilityServiceWarning
                         .createDisableDialog(getPrefContext(), info,
                                 this::onDialogButtonFromDisableToggleClicked);
                 break;
             }
             default: {
-                mDialog = super.onCreateDialog(dialogId);
+                mWarningDialog = super.onCreateDialog(dialogId);
             }
         }
-        return mDialog;
+        return mWarningDialog;
     }
 
     @Override
@@ -402,7 +404,7 @@ public class ToggleAccessibilityServicePreferenceFragment extends
     }
 
     private void onDialogButtonFromUninstallClicked() {
-        mDialog.dismiss();
+        mWarningDialog.dismiss();
         final Intent uninstallIntent = createUninstallPackageActivityIntent();
         if (uninstallIntent == null) {
             return;
@@ -436,12 +438,12 @@ public class ToggleAccessibilityServicePreferenceFragment extends
             mIsDialogShown.set(false);
             showPopupDialog(DialogEnums.LAUNCH_ACCESSIBILITY_TUTORIAL);
         }
-        mDialog.dismiss();
+        mWarningDialog.dismiss();
     }
 
     private void onDenyButtonFromEnableToggleClicked() {
         handleConfirmServiceEnabled(/* confirmed= */ false);
-        mDialog.dismiss();
+        mWarningDialog.dismiss();
     }
 
     void onDialogButtonFromShortcutToggleClicked(View view) {
@@ -465,7 +467,7 @@ public class ToggleAccessibilityServicePreferenceFragment extends
         mIsDialogShown.set(false);
         showPopupDialog(DialogEnums.LAUNCH_ACCESSIBILITY_TUTORIAL);
 
-        mDialog.dismiss();
+        mWarningDialog.dismiss();
 
         mShortcutPreference.setSummary(getShortcutTypeSummary(getPrefContext()));
     }
@@ -473,7 +475,7 @@ public class ToggleAccessibilityServicePreferenceFragment extends
     private void onDenyButtonFromShortcutToggleClicked() {
         mShortcutPreference.setChecked(false);
 
-        mDialog.dismiss();
+        mWarningDialog.dismiss();
     }
 
     void onDialogButtonFromShortcutClicked(View view) {
@@ -491,11 +493,11 @@ public class ToggleAccessibilityServicePreferenceFragment extends
         mIsDialogShown.set(false);
         showPopupDialog(DialogEnums.EDIT_SHORTCUT);
 
-        mDialog.dismiss();
+        mWarningDialog.dismiss();
     }
 
     private void onDenyButtonFromShortcutClicked() {
-        mDialog.dismiss();
+        mWarningDialog.dismiss();
     }
 
     private boolean onPreferenceClick(boolean isChecked) {

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

@@ -25,7 +25,6 @@ import android.app.settings.SettingsEnums;
 import android.content.ContentResolver;
 import android.net.Uri;
 import android.os.Bundle;
-import android.os.Handler;
 import android.provider.Settings;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -41,8 +40,6 @@ import java.util.List;
 public class ToggleColorInversionPreferenceFragment extends ToggleFeaturePreferenceFragment {
 
     private static final String ENABLED = Settings.Secure.ACCESSIBILITY_DISPLAY_INVERSION_ENABLED;
-    private final Handler mHandler = new Handler();
-    private SettingsContentObserver mSettingsContentObserver;
 
     @Override
     public int getMetricsCategory() {
@@ -86,20 +83,22 @@ public class ToggleColorInversionPreferenceFragment extends ToggleFeaturePrefere
                 .authority(getPrefContext().getPackageName())
                 .appendPath(String.valueOf(R.raw.accessibility_color_inversion_banner))
                 .build();
-        final List<String> enableServiceFeatureKeys = new ArrayList<>(/* initialCapacity= */ 1);
-        enableServiceFeatureKeys.add(ENABLED);
-        mSettingsContentObserver = new SettingsContentObserver(mHandler, enableServiceFeatureKeys) {
-            @Override
-            public void onChange(boolean selfChange, Uri uri) {
-                updateSwitchBarToggleSwitch();
-            }
-        };
-
         final View view = super.onCreateView(inflater, container, savedInstanceState);
         updateFooterPreference();
         return view;
     }
 
+    @Override
+    protected void registerKeysToObserverCallback(
+            AccessibilitySettingsContentObserver contentObserver) {
+        super.registerKeysToObserverCallback(contentObserver);
+
+        final List<String> enableServiceFeatureKeys = new ArrayList<>(/* initialCapacity= */ 1);
+        enableServiceFeatureKeys.add(ENABLED);
+        contentObserver.registerKeysToObserverCallback(enableServiceFeatureKeys,
+                key -> updateSwitchBarToggleSwitch());
+    }
+
     private void updateFooterPreference() {
         final String title = getPrefContext().getString(
                 R.string.accessibility_color_inversion_about_title);
@@ -114,12 +113,10 @@ public class ToggleColorInversionPreferenceFragment extends ToggleFeaturePrefere
     public void onResume() {
         super.onResume();
         updateSwitchBarToggleSwitch();
-        mSettingsContentObserver.register(getContentResolver());
     }
 
     @Override
     public void onPause() {
-        mSettingsContentObserver.unregister(getContentResolver());
         super.onPause();
     }
 

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

@@ -24,9 +24,7 @@ import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
 import android.app.settings.SettingsEnums;
 import android.content.Context;
 import android.content.res.Resources;
-import android.net.Uri;
 import android.os.Bundle;
-import android.os.Handler;
 import android.provider.Settings;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -53,8 +51,6 @@ public final class ToggleDaltonizerPreferenceFragment extends ToggleFeaturePrefe
     private static final String KEY_PREVIEW = "daltonizer_preview";
     private static final String KEY_CATEGORY_MODE = "daltonizer_mode_category";
     private static final List<AbstractPreferenceController> sControllers = new ArrayList<>();
-    private final Handler mHandler = new Handler();
-    private SettingsContentObserver mSettingsContentObserver;
 
     private static List<AbstractPreferenceController> buildPreferenceControllers(Context context,
             Lifecycle lifecycle) {
@@ -84,20 +80,22 @@ public final class ToggleDaltonizerPreferenceFragment extends ToggleFeaturePrefe
         mComponentName = DALTONIZER_COMPONENT_NAME;
         mPackageName = getText(R.string.accessibility_display_daltonizer_preference_title);
         mHtmlDescription = getText(R.string.accessibility_display_daltonizer_preference_subtitle);
-        final List<String> enableServiceFeatureKeys = new ArrayList<>(/* initialCapacity= */ 1);
-        enableServiceFeatureKeys.add(ENABLED);
-        mSettingsContentObserver = new SettingsContentObserver(mHandler, enableServiceFeatureKeys) {
-            @Override
-            public void onChange(boolean selfChange, Uri uri) {
-                updateSwitchBarToggleSwitch();
-            }
-        };
-
         final View view = super.onCreateView(inflater, container, savedInstanceState);
         updateFooterPreference();
         return view;
     }
 
+    @Override
+    protected void registerKeysToObserverCallback(
+            AccessibilitySettingsContentObserver contentObserver) {
+        super.registerKeysToObserverCallback(contentObserver);
+
+        final List<String> enableServiceFeatureKeys = new ArrayList<>(/* initialCapacity= */ 1);
+        enableServiceFeatureKeys.add(ENABLED);
+        contentObserver.registerKeysToObserverCallback(enableServiceFeatureKeys,
+                key -> updateSwitchBarToggleSwitch());
+    }
+
     private void updateFooterPreference() {
         final String title = getPrefContext()
                 .getString(R.string.accessibility_daltonizer_about_title);
@@ -123,8 +121,6 @@ public final class ToggleDaltonizerPreferenceFragment extends ToggleFeaturePrefe
     public void onResume() {
         super.onResume();
         updateSwitchBarToggleSwitch();
-        mSettingsContentObserver.register(getContentResolver());
-
         for (AbstractPreferenceController controller :
                 buildPreferenceControllers(getPrefContext(), getSettingsLifecycle())) {
             ((DaltonizerRadioButtonPreferenceController) controller).setOnChangeListener(this);
@@ -135,7 +131,6 @@ public final class ToggleDaltonizerPreferenceFragment extends ToggleFeaturePrefe
 
     @Override
     public void onPause() {
-        mSettingsContentObserver.unregister(getContentResolver());
         for (AbstractPreferenceController controller :
                 buildPreferenceControllers(getPrefContext(), getSettingsLifecycle())) {
             ((DaltonizerRadioButtonPreferenceController) controller).setOnChangeListener(null);

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

@@ -99,7 +99,7 @@ public abstract class ToggleFeaturePreferenceFragment extends SettingsPreference
     protected static final String KEY_ANIMATED_IMAGE = "animated_image";
 
     private TouchExplorationStateChangeListener mTouchExplorationStateChangeListener;
-    private SettingsContentObserver mSettingsContentObserver;
+    private AccessibilitySettingsContentObserver mSettingsContentObserver;
 
     private CheckBox mSoftwareTypeCheckBox;
     private CheckBox mHardwareTypeCheckBox;
@@ -143,17 +143,21 @@ public abstract class ToggleFeaturePreferenceFragment extends SettingsPreference
             setPreferenceScreen(preferenceScreen);
         }
 
-        final List<String> shortcutFeatureKeys = getFeatureSettingsKeys();
+        mSettingsContentObserver = new AccessibilitySettingsContentObserver(new Handler());
-        mSettingsContentObserver = new SettingsContentObserver(new Handler(), shortcutFeatureKeys) {
+        registerKeysToObserverCallback(mSettingsContentObserver);
-            @Override
-            public void onChange(boolean selfChange, Uri uri) {
-                updateShortcutPreferenceData();
-                updateShortcutPreference();
-            }
-        };
     }
 
-    protected List<String> getFeatureSettingsKeys() {
+    protected void registerKeysToObserverCallback(
+            AccessibilitySettingsContentObserver contentObserver) {
+        final List<String> shortcutFeatureKeys = getShortcutFeatureSettingsKeys();
+
+        contentObserver.registerKeysToObserverCallback(shortcutFeatureKeys, key -> {
+            updateShortcutPreferenceData();
+            updateShortcutPreference();
+        });
+    }
+
+    protected List<String> getShortcutFeatureSettingsKeys() {
         final List<String> shortcutFeatureKeys = new ArrayList<>();
         shortcutFeatureKeys.add(Settings.Secure.ACCESSIBILITY_BUTTON_TARGETS);
         shortcutFeatureKeys.add(Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE);

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

@@ -22,7 +22,6 @@ import android.content.Context;
 import android.hardware.display.ColorDisplayManager;
 import android.net.Uri;
 import android.os.Bundle;
-import android.os.Handler;
 import android.provider.Settings;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -50,8 +49,6 @@ public class ToggleReduceBrightColorsPreferenceFragment extends ToggleFeaturePre
     private static final String KEY_INTENSITY = "rbc_intensity";
     private static final String KEY_PERSIST = "rbc_persist";
 
-    private final Handler mHandler = new Handler();
-    private SettingsContentObserver mSettingsContentObserver;
     private ReduceBrightColorsIntensityPreferenceController mRbcIntensityPreferenceController;
     private ReduceBrightColorsPersistencePreferenceController mRbcPersistencePreferenceController;
     private ColorDisplayManager mColorDisplayManager;
@@ -67,20 +64,12 @@ public class ToggleReduceBrightColorsPreferenceFragment extends ToggleFeaturePre
         mComponentName = AccessibilityShortcutController.REDUCE_BRIGHT_COLORS_COMPONENT_NAME;
         mPackageName = getText(R.string.reduce_bright_colors_preference_title);
         mHtmlDescription = getText(R.string.reduce_bright_colors_preference_subtitle);
-        final List<String> enableServiceFeatureKeys = new ArrayList<>(/* initialCapacity= */ 1);
-        enableServiceFeatureKeys.add(REDUCE_BRIGHT_COLORS_ACTIVATED_KEY);
         mRbcIntensityPreferenceController =
                 new ReduceBrightColorsIntensityPreferenceController(getContext(), KEY_INTENSITY);
         mRbcPersistencePreferenceController =
                 new ReduceBrightColorsPersistencePreferenceController(getContext(), KEY_PERSIST);
         mRbcIntensityPreferenceController.displayPreference(getPreferenceScreen());
         mRbcPersistencePreferenceController.displayPreference(getPreferenceScreen());
-        mSettingsContentObserver = new SettingsContentObserver(mHandler, enableServiceFeatureKeys) {
-            @Override
-            public void onChange(boolean selfChange, Uri uri) {
-                updateSwitchBarToggleSwitch();
-            }
-        };
         mColorDisplayManager = getContext().getSystemService(ColorDisplayManager.class);
         final View view = super.onCreateView(inflater, container, savedInstanceState);
         // Parent sets the title when creating the view, so set it after calling super
@@ -90,6 +79,17 @@ public class ToggleReduceBrightColorsPreferenceFragment extends ToggleFeaturePre
         return view;
     }
 
+    @Override
+    protected void registerKeysToObserverCallback(
+            AccessibilitySettingsContentObserver contentObserver) {
+        super.registerKeysToObserverCallback(contentObserver);
+
+        final List<String> enableServiceFeatureKeys = new ArrayList<>(/* initialCapacity= */ 1);
+        enableServiceFeatureKeys.add(REDUCE_BRIGHT_COLORS_ACTIVATED_KEY);
+        contentObserver.registerKeysToObserverCallback(enableServiceFeatureKeys,
+                key -> updateSwitchBarToggleSwitch());
+    }
+
     private void updateGeneralCategoryOrder() {
         final PreferenceCategory generalCategory = findPreference(KEY_GENERAL_CATEGORY);
         final SeekBarPreference intensity = findPreference(KEY_INTENSITY);
@@ -117,12 +117,10 @@ public class ToggleReduceBrightColorsPreferenceFragment extends ToggleFeaturePre
     public void onResume() {
         super.onResume();
         updateSwitchBarToggleSwitch();
-        mSettingsContentObserver.register(getContentResolver());
     }
 
     @Override
     public void onPause() {
-        mSettingsContentObserver.unregister(getContentResolver());
         super.onPause();
     }
 

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

@@ -75,6 +75,7 @@ public class ToggleScreenMagnificationPreferenceFragment extends
             new TextUtils.SimpleStringSplitter(COMPONENT_NAME_SEPARATOR);
 
     private DialogCreatable mDialogDelegate;
+    private MagnificationFollowTypingPreferenceController mFollowTypingPreferenceController;
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -187,11 +188,10 @@ public class ToggleScreenMagnificationPreferenceFragment extends
                 MagnificationFollowTypingPreferenceController.PREF_KEY);
         generalCategory.addPreference(followingTypingSwitchPreference);
 
-        final MagnificationFollowTypingPreferenceController followTypingPreferenceController =
+        mFollowTypingPreferenceController = new MagnificationFollowTypingPreferenceController(
-                new MagnificationFollowTypingPreferenceController(getContext(),
+                getContext(), MagnificationFollowTypingPreferenceController.PREF_KEY);
-                        MagnificationFollowTypingPreferenceController.PREF_KEY);
+        getSettingsLifecycle().addObserver(mFollowTypingPreferenceController);
-        getSettingsLifecycle().addObserver(followTypingPreferenceController);
+        mFollowTypingPreferenceController.displayPreference(getPreferenceScreen());
-        followTypingPreferenceController.displayPreference(getPreferenceScreen());
     }
 
     @Override
@@ -293,8 +293,23 @@ public class ToggleScreenMagnificationPreferenceFragment extends
     }
 
     @Override
-    protected List<String> getFeatureSettingsKeys() {
+    protected void registerKeysToObserverCallback(
-        final List<String> shortcutKeys = super.getFeatureSettingsKeys();
+            AccessibilitySettingsContentObserver contentObserver) {
+        super.registerKeysToObserverCallback(contentObserver);
+
+        final List<String> followingTypingKeys = new ArrayList<>();
+        followingTypingKeys.add(Settings.Secure.ACCESSIBILITY_MAGNIFICATION_FOLLOW_TYPING_ENABLED);
+        contentObserver.registerKeysToObserverCallback(followingTypingKeys,
+                key -> updateFollowTypingState());
+    }
+
+    private void updateFollowTypingState() {
+        mFollowTypingPreferenceController.updateState();
+    }
+
+    @Override
+    protected List<String> getShortcutFeatureSettingsKeys() {
+        final List<String> shortcutKeys = super.getShortcutFeatureSettingsKeys();
         shortcutKeys.add(Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_ENABLED);
         return shortcutKeys;
     }

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

@@ -0,0 +1,160 @@
+/*
+ * 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.never;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.database.ContentObserver;
+import android.os.Handler;
+import android.provider.Settings;
+
+import androidx.test.core.app.ApplicationProvider;
+
+import org.junit.After;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.shadow.api.Shadow;
+import org.robolectric.shadows.ShadowContentResolver;
+
+import java.util.Collection;
+import java.util.List;
+
+/** Test for {@link AccessibilitySettingsContentObserver}. */
+@RunWith(RobolectricTestRunner.class)
+public class AccessibilitySettingsContentObserverTest {
+
+    private static final String SPECIFIC_KEY_A_1 = "SPECIFIC_KEY_A_1";
+    private static final String SPECIFIC_KEY_A_2 = "SPECIFIC_KEY_A_2";
+    private static final String SPECIFIC_KEY_B_1 = "SPECIFIC_KEY_B_1";
+
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+    private final AccessibilitySettingsContentObserver mObserver =
+            new AccessibilitySettingsContentObserver(new Handler());
+    private final AccessibilitySettingsContentObserver.ContentObserverCallback mObserverCallbackA =
+            spy(new TestableContentObserverCallback());
+    private final AccessibilitySettingsContentObserver.ContentObserverCallback mObserverCallbackB =
+            spy(new TestableContentObserverCallback());
+    private final ContentResolver mContentResolver = mContext.getContentResolver();
+
+    @Test
+    public void register_shouldRegisterContentObserverForDefaultKeys() {
+        mObserver.register(mContentResolver);
+
+        ShadowContentResolver shadowContentResolver = Shadow.extract(mContentResolver);
+        assertObserverToUri(shadowContentResolver,
+                Settings.Secure.ACCESSIBILITY_ENABLED, mObserver);
+        assertObserverToUri(shadowContentResolver,
+                Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES, mObserver);
+    }
+
+    @Test
+    public void unregister_shouldUnregisterContentObserver() {
+        mObserver.register(mContentResolver);
+
+        mObserver.unregister(mContentResolver);
+
+        ShadowContentResolver shadowContentResolver = Shadow.extract(mContentResolver);
+        assertNotObserverToUri(shadowContentResolver, Settings.Secure.ACCESSIBILITY_ENABLED);
+        assertNotObserverToUri(shadowContentResolver,
+                Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES);
+    }
+
+    @Test
+    public void register_addSpecificKeys_shouldRegisterContentObserverForSpecificAndDefaultKeys() {
+        mObserver.registerKeysToObserverCallback(List.of(SPECIFIC_KEY_A_1), mObserverCallbackA);
+
+        mObserver.register(mContentResolver);
+
+        ShadowContentResolver shadowContentResolver = Shadow.extract(mContentResolver);
+        assertObserverToUri(shadowContentResolver,
+                Settings.Secure.ACCESSIBILITY_ENABLED, mObserver);
+        assertObserverToUri(shadowContentResolver,
+                Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES, mObserver);
+        assertObserverToUri(shadowContentResolver, SPECIFIC_KEY_A_1, mObserver);
+    }
+
+    @Test
+    public void onChange_shouldTriggerCallbackOnDefaultKey() {
+        mObserver.registerObserverCallback(mObserverCallbackA);
+        mObserver.register(mContentResolver);
+
+        mObserver.onChange(/* selfChange= */ false,
+                Settings.Secure.getUriFor(Settings.Secure.ACCESSIBILITY_ENABLED));
+
+        verify(mObserverCallbackA).onChange(Settings.Secure.ACCESSIBILITY_ENABLED);
+    }
+
+    @Test
+    public void onChange_registerSpecificKeys_shouldTriggerSpecificCallback() {
+        mObserver.registerKeysToObserverCallback(
+                List.of(SPECIFIC_KEY_A_1, SPECIFIC_KEY_A_2), mObserverCallbackA);
+        mObserver.register(mContentResolver);
+
+        mObserver.onChange(/* selfChange= */ false,
+                Settings.Secure.getUriFor(SPECIFIC_KEY_A_2));
+
+        verify(mObserverCallbackA).onChange(SPECIFIC_KEY_A_2);
+    }
+
+    @Test
+    public void onChange_registerSpecificKeys_withoutTriggerOtherCallback() {
+        mObserver.registerKeysToObserverCallback(
+                List.of(SPECIFIC_KEY_A_1, SPECIFIC_KEY_A_2), mObserverCallbackA);
+        mObserver.registerKeysToObserverCallback(
+                List.of(SPECIFIC_KEY_B_1), mObserverCallbackB);
+        mObserver.register(mContentResolver);
+
+        mObserver.onChange(/* selfChange= */ false,
+                Settings.Secure.getUriFor(SPECIFIC_KEY_B_1));
+
+        verify(mObserverCallbackA, never()).onChange(SPECIFIC_KEY_A_1);
+        verify(mObserverCallbackA, never()).onChange(SPECIFIC_KEY_A_2);
+        verify(mObserverCallbackA, never()).onChange(SPECIFIC_KEY_B_1);
+        verify(mObserverCallbackB).onChange(SPECIFIC_KEY_B_1);
+    }
+
+    @After
+    public void tearDown() {
+        mObserver.unregister(mContentResolver);
+    }
+
+    private void assertNotObserverToUri(ShadowContentResolver resolver, String key) {
+        assertThat(resolver.getContentObservers(Settings.Secure.getUriFor(key))).isEmpty();
+    }
+
+    private void assertObserverToUri(ShadowContentResolver resolver,
+            String key, ContentObserver observer) {
+        Collection<ContentObserver> observers =
+                resolver.getContentObservers(Settings.Secure.getUriFor(key));
+        assertThat(observers).contains(observer);
+    }
+
+    private static class TestableContentObserverCallback implements
+            AccessibilitySettingsContentObserver.ContentObserverCallback {
+        @Override
+        public void onChange(String key) {
+            // do nothing
+        }
+    }
+}

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

@@ -281,10 +281,10 @@ public class AccessibilitySettingsTest {
         verify(mContentResolver).registerContentObserver(
                 eq(Settings.Secure.getUriFor(Settings.Secure.ACCESSIBILITY_BUTTON_TARGETS)),
                 anyBoolean(),
-                any(SettingsContentObserver.class));
+                any(AccessibilitySettingsContentObserver.class));
         verify(mContentResolver).registerContentObserver(eq(Settings.Secure.getUriFor(
                 Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE)), anyBoolean(),
-                any(SettingsContentObserver.class));
+                any(AccessibilitySettingsContentObserver.class));
         verify(mActivity, atLeast(1)).registerReceiver(any(PackageMonitor.class), captor.capture(),
                 isNull(), any());
         intentFilter = captor.getAllValues().get(/* first time */ 0);
@@ -301,7 +301,8 @@ public class AccessibilitySettingsTest {
 
         mFragment.onDestroy();
 
-        verify(mContentResolver).unregisterContentObserver(any(SettingsContentObserver.class));
+        verify(mContentResolver).unregisterContentObserver(
+                any(AccessibilitySettingsContentObserver.class));
         verify(mActivity).unregisterReceiver(any(PackageMonitor.class));
 
     }

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

@@ -94,4 +94,15 @@ public class MagnificationFollowTypingPreferenceControllerTest {
         assertThat(mController.isChecked()).isFalse();
         assertThat(mSwitchPreference.isChecked()).isFalse();
     }
+
+    @Test
+    public void updateState_disableFollowTyping_shouldReturnFalse() {
+        Settings.Secure.putInt(mContext.getContentResolver(), KEY_FOLLOW_TYPING, OFF);
+
+        mController.updateState();
+
+        verify(mSwitchPreference).setChecked(false);
+        assertThat(mController.isChecked()).isFalse();
+        assertThat(mSwitchPreference.isChecked()).isFalse();
+    }
 }

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

@@ -20,6 +20,8 @@ import static com.android.settings.accessibility.ToggleFeaturePreferenceFragment
 
 import static com.google.common.truth.Truth.assertThat;
 
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
@@ -27,6 +29,7 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import android.content.ComponentName;
+import android.content.ContentResolver;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.os.Bundle;
@@ -75,12 +78,16 @@ public class ToggleFeaturePreferenceFragmentTest {
             Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE;
 
     private TestToggleFeaturePreferenceFragment mFragment;
-    private PreferenceScreen mScreen;
+    private final Context mContext = ApplicationProvider.getApplicationContext();
-    private Context mContext = ApplicationProvider.getApplicationContext();
 
     @Mock(answer = Answers.RETURNS_DEEP_STUBS)
     private PreferenceManager mPreferenceManager;
 
+    @Mock
+    private FragmentActivity mActivity;
+    @Mock
+    private ContentResolver mContentResolver;
+
     @Before
     public void setUpTestFragment() {
         MockitoAnnotations.initMocks(this);
@@ -89,9 +96,11 @@ public class ToggleFeaturePreferenceFragmentTest {
         when(mFragment.getPreferenceManager()).thenReturn(mPreferenceManager);
         when(mFragment.getPreferenceManager().getContext()).thenReturn(mContext);
         when(mFragment.getContext()).thenReturn(mContext);
-        mScreen = spy(new PreferenceScreen(mContext, null));
+        when(mFragment.getActivity()).thenReturn(mActivity);
-        when(mScreen.getPreferenceManager()).thenReturn(mPreferenceManager);
+        when(mActivity.getContentResolver()).thenReturn(mContentResolver);
-        doReturn(mScreen).when(mFragment).getPreferenceScreen();
+        final PreferenceScreen screen = spy(new PreferenceScreen(mContext, null));
+        when(screen.getPreferenceManager()).thenReturn(mPreferenceManager);
+        doReturn(screen).when(mFragment).getPreferenceScreen();
     }
 
     @Test
@@ -103,6 +112,25 @@ public class ToggleFeaturePreferenceFragmentTest {
         verify(mFragment).addPreferencesFromResource(R.xml.placeholder_prefs);
     }
 
+    @Test
+    @Config(shadows = {ShadowFragment.class})
+    public void onResume_haveRegisterToSpecificUris() {
+        mFragment.onAttach(mContext);
+        mFragment.onCreate(Bundle.EMPTY);
+
+        mFragment.onResume();
+
+        verify(mContentResolver).registerContentObserver(
+                eq(Settings.Secure.getUriFor(Settings.Secure.ACCESSIBILITY_BUTTON_TARGETS)),
+                eq(false),
+                any(AccessibilitySettingsContentObserver.class));
+        verify(mContentResolver).registerContentObserver(
+                eq(Settings.Secure.getUriFor(
+                        Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE)),
+                eq(false),
+                any(AccessibilitySettingsContentObserver.class));
+    }
+
     @Test
     public void updateShortcutPreferenceData_assignDefaultValueToVariable() {
         mFragment.mComponentName = PLACEHOLDER_COMPONENT_NAME;

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

@@ -25,14 +25,15 @@ import static com.google.common.truth.Truth.assertThat;
 
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.RETURNS_DEEP_STUBS;
-import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import android.content.ComponentName;
+import android.content.ContentResolver;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.res.Resources;
@@ -63,8 +64,8 @@ import org.junit.Before;
 import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
-import org.robolectric.Robolectric;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
@@ -96,17 +97,22 @@ public class ToggleScreenMagnificationPreferenceFragmentTest {
     private Context mContext;
     private Resources mResources;
 
+    @Mock
+    private FragmentActivity mActivity;
+    @Mock
+    private ContentResolver mContentResolver;
+
     @Before
     public void setUpTestFragment() {
         MockitoAnnotations.initMocks(this);
 
         mContext = spy(ApplicationProvider.getApplicationContext());
-        final FragmentActivity activity = Robolectric.setupActivity(FragmentActivity.class);
         mFragment = spy(new TestToggleScreenMagnificationPreferenceFragment(mContext));
         mResources = spy(mContext.getResources());
         when(mContext.getResources()).thenReturn(mResources);
         when(mFragment.getContext().getResources()).thenReturn(mResources);
-        doReturn(activity).when(mFragment).getActivity();
+        when(mFragment.getActivity()).thenReturn(mActivity);
+        when(mActivity.getContentResolver()).thenReturn(mContentResolver);
     }
 
     @Ignore("Ignore it since a NPE is happened in ShadowWindowManagerGlobal. (Ref. b/214161063)")
@@ -142,6 +148,30 @@ public class ToggleScreenMagnificationPreferenceFragmentTest {
         assertThat(switchPreference.isChecked()).isFalse();
     }
 
+    @Test
+    @Config(shadows = {ShadowFragment.class})
+    public void onResume_haveRegisterToSpecificUris() {
+        mFragment.onAttach(mContext);
+        mFragment.onCreate(Bundle.EMPTY);
+
+        mFragment.onResume();
+
+        verify(mContentResolver).registerContentObserver(
+                eq(Settings.Secure.getUriFor(Settings.Secure.ACCESSIBILITY_BUTTON_TARGETS)),
+                eq(false),
+                any(AccessibilitySettingsContentObserver.class));
+        verify(mContentResolver).registerContentObserver(
+                eq(Settings.Secure.getUriFor(
+                        Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE)),
+                eq(false),
+                any(AccessibilitySettingsContentObserver.class));
+        verify(mContentResolver).registerContentObserver(
+                eq(Settings.Secure.getUriFor(
+                        Settings.Secure.ACCESSIBILITY_MAGNIFICATION_FOLLOW_TYPING_ENABLED)),
+                eq(false),
+                any(AccessibilitySettingsContentObserver.class));
+    }
+
     @Test
     public void hasValueInSettings_putValue_hasValue() {
         setMagnificationTripleTapEnabled(/* enabled= */ true);