Merge "a11y: Clean up magnification mode controller and fix lint errors" into main

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

@@ -24,6 +24,7 @@ import android.content.DialogInterface;
 import android.view.View;
 import android.widget.AbsListView;
 import android.widget.AdapterView;
+import android.widget.ListAdapter;
 import android.widget.ListView;
 import android.widget.ScrollView;
 
@@ -34,14 +35,15 @@ import androidx.appcompat.app.AlertDialog;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * Utility class for creating the edit dialog.
  */
 public class AccessibilityDialogUtils {
-    private static final String TAG = "AccessibilityDialogUtils";
+    private static final String TAG = AccessibilityDialogUtils.class.getSimpleName();
 
-    /** Denotes the dialog emuns for show dialog. */
+    /** Denotes the dialog enums for show dialog. */
     @Retention(RetentionPolicy.SOURCE)
     public @interface DialogEnums {
         /**
@@ -89,6 +91,19 @@ public class AccessibilityDialogUtils {
          * OPEN: Settings > Accessibility > Display size and text > Click 'Reset settings' button.
          */
         int DIALOG_RESET_SETTINGS = 1009;
+
+        /**
+         * OPEN: Settings > Accessibility > Magnification > Magnification type.
+         */
+        int DIALOG_MAGNIFICATION_MODE = 1010;
+
+        /**
+         * Enable: Settings > Accessibility > Magnification > Magnification shortcut > Advanced >
+         * Triple tap.
+         * OPEN: Settings > Accessibility > Magnification > Magnification type > Magnify part of
+         * screen / Switch between full and partial screen > Save.
+         */
+        int DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING = 1011;
     }
 
     /**
@@ -118,17 +133,26 @@ public class AccessibilityDialogUtils {
      *                         is clicked
      * @return the {@link Dialog} with the given view
      */
-    public static Dialog createCustomDialog(Context context, CharSequence dialogTitle,
+    @NonNull
-            View customView, CharSequence positiveButtonText,
+    public static Dialog createCustomDialog(@NonNull Context context,
-            DialogInterface.OnClickListener positiveListener, CharSequence negativeButtonText,
+            @NonNull CharSequence dialogTitle, @Nullable View customView,
-            DialogInterface.OnClickListener negativeListener) {
+            @NonNull CharSequence positiveButtonText,
-        final AlertDialog alertDialog = new AlertDialog.Builder(context)
+            @Nullable DialogInterface.OnClickListener positiveListener,
-                .setView(customView)
+            @NonNull CharSequence negativeButtonText,
+            @Nullable DialogInterface.OnClickListener negativeListener) {
+        DialogInterface.OnClickListener doNothingListener =
+                (DialogInterface dialogInterface, int which) -> {};
+        final AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(context)
                 .setTitle(dialogTitle)
                 .setCancelable(true)
-                .setPositiveButton(positiveButtonText, positiveListener)
+                .setPositiveButton(positiveButtonText,
-                .setNegativeButton(negativeButtonText, negativeListener)
+                        Optional.ofNullable(positiveListener).orElse(doNothingListener))
-                .create();
+                .setNegativeButton(negativeButtonText,
+                        Optional.ofNullable(negativeListener).orElse(doNothingListener));
+        if (customView != null) {
+            dialogBuilder.setView(customView);
+        }
+        final AlertDialog alertDialog = dialogBuilder.create();
         if (customView instanceof ScrollView || customView instanceof AbsListView) {
             setScrollIndicators(customView);
         }
@@ -151,8 +175,7 @@ public class AccessibilityDialogUtils {
         list.setId(android.R.id.list);
         list.setDivider(/* divider= */ null);
         list.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
-        final ItemInfoArrayAdapter
+        final ListAdapter adapter = new ItemInfoArrayAdapter<>(context, itemInfoList);
-                adapter = new ItemInfoArrayAdapter(context, itemInfoList);
         list.setAdapter(adapter);
         list.setOnItemClickListener(itemListener);
         return list;

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

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2025 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;
+
+/**
+ * The {@code DialogHelper} interface provides methods for displaying dialogs.
+ * It helps the dialog delegate to show the dialog, and will be injected to the dialog delegate.
+ */
+public interface DialogHelper {
+    /**
+     * Shows a dialog with the specified dialog ID.
+     *
+     * @param dialogId The ID of the dialog to display.
+     */
+    void showDialog(int dialogId);
+}

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

@@ -37,11 +37,13 @@ import androidx.annotation.DrawableRes;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
+import androidx.core.util.Preconditions;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceScreen;
 
 import com.android.settings.DialogCreatable;
 import com.android.settings.R;
+import com.android.settings.accessibility.AccessibilityDialogUtils.DialogEnums;
 import com.android.settings.accessibility.MagnificationCapabilities.MagnificationMode;
 import com.android.settings.core.BasePreferenceController;
 import com.android.settings.utils.AnnotationSpan;
@@ -57,33 +59,37 @@ public class MagnificationModePreferenceController extends BasePreferenceControl
         DialogCreatable, LifecycleObserver, OnCreate, OnSaveInstanceState {
 
     static final String PREF_KEY = "screen_magnification_mode";
-    private static final int DIALOG_ID_BASE = 10;
-    @VisibleForTesting
-    static final int DIALOG_MAGNIFICATION_MODE = DIALOG_ID_BASE + 1;
-    @VisibleForTesting
-    static final int DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING = DIALOG_ID_BASE + 2;
-    @VisibleForTesting
     static final String EXTRA_MODE = "mode";
 
-    private static final String TAG = "MagnificationModePreferenceController";
+    private static final String TAG = MagnificationModePreferenceController.class.getSimpleName();
 
+    @Nullable
     private DialogHelper mDialogHelper;
     // The magnification mode in the dialog.
     @MagnificationMode
     private int mModeCache = MagnificationMode.NONE;
+    @Nullable
     private Preference mModePreference;
+    @Nullable
     private ShortcutPreference mLinkPreference;
 
     @VisibleForTesting
+    @Nullable
     ListView mMagnificationModesListView;
 
     private final List<MagnificationModeInfo> mModeInfos = new ArrayList<>();
 
-    public MagnificationModePreferenceController(Context context, String preferenceKey) {
+    public MagnificationModePreferenceController(@NonNull Context context,
+            @NonNull String preferenceKey) {
         super(context, preferenceKey);
         initModeInfos();
     }
 
+
+    public void setDialogHelper(@NonNull DialogHelper dialogHelper) {
+        mDialogHelper = dialogHelper;
+    }
+
     private void initModeInfos() {
         mModeInfos.add(new MagnificationModeInfo(mContext.getText(
                 R.string.accessibility_magnification_mode_dialog_option_full_screen), null,
@@ -103,6 +109,7 @@ public class MagnificationModePreferenceController extends BasePreferenceControl
         return AVAILABLE;
     }
 
+    @NonNull
     @Override
     public CharSequence getSummary() {
         final int capabilities = MagnificationCapabilities.getCapabilities(mContext);
@@ -110,99 +117,98 @@ public class MagnificationModePreferenceController extends BasePreferenceControl
     }
 
     @Override
-    public void onCreate(Bundle savedInstanceState) {
+    public void onCreate(@Nullable Bundle savedInstanceState) {
         if (savedInstanceState != null) {
             mModeCache = savedInstanceState.getInt(EXTRA_MODE, MagnificationMode.NONE);
         }
     }
 
     @Override
-    public void displayPreference(PreferenceScreen screen) {
+    public void displayPreference(@NonNull PreferenceScreen screen) {
         super.displayPreference(screen);
         mModePreference = screen.findPreference(getPreferenceKey());
         mLinkPreference = screen.findPreference(
                 ToggleFeaturePreferenceFragment.KEY_SHORTCUT_PREFERENCE);
-        mModePreference.setOnPreferenceClickListener(preference -> {
+        Preconditions.checkNotNull(mModePreference).setOnPreferenceClickListener(preference -> {
             mModeCache = MagnificationCapabilities.getCapabilities(mContext);
-            mDialogHelper.showDialog(DIALOG_MAGNIFICATION_MODE);
+            Preconditions.checkNotNull(mDialogHelper).showDialog(
+                    DialogEnums.DIALOG_MAGNIFICATION_MODE);
             return true;
         });
     }
 
     @Override
-    public void onSaveInstanceState(Bundle outState) {
+    public void onSaveInstanceState(@NonNull Bundle outState) {
         outState.putInt(EXTRA_MODE, mModeCache);
     }
 
-    /**
+    @NonNull
-     * Sets {@link DialogHelper} used to show the dialog.
-     */
-    public void setDialogHelper(DialogHelper dialogHelper) {
-        mDialogHelper = dialogHelper;
-        mDialogHelper.setDialogDelegate(this);
-    }
-
     @Override
     public Dialog onCreateDialog(int dialogId) {
-        switch (dialogId) {
+        return switch (dialogId) {
-            case DIALOG_MAGNIFICATION_MODE:
+            case DialogEnums.DIALOG_MAGNIFICATION_MODE -> createMagnificationModeDialog();
-                return createMagnificationModeDialog();
+            case DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING ->
-
+                    createMagnificationTripleTapWarningDialog();
-            case DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING:
+            default -> throw new IllegalArgumentException(
-                return createMagnificationTripleTapWarningDialog();
+                    "This only handles magnification mode and triple tap warning dialog");
-        }
+        };
-        return null;
     }
 
     @Override
     public int getDialogMetricsCategory(int dialogId) {
-        switch (dialogId) {
+        return switch (dialogId) {
-            case DIALOG_MAGNIFICATION_MODE:
+            case DialogEnums.DIALOG_MAGNIFICATION_MODE ->
-                return SettingsEnums.DIALOG_MAGNIFICATION_CAPABILITY;
+                    SettingsEnums.DIALOG_MAGNIFICATION_CAPABILITY;
-            case DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING:
+            case DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING ->
-                return SettingsEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING;
+                    SettingsEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING;
-            default:
+            default -> 0;
-                return 0;
+        };
-        }
     }
 
+    @NonNull
+    private ListView getMagnificationModesListView() {
+        return Preconditions.checkNotNull(mMagnificationModesListView);
+    }
+
+    @NonNull
     private Dialog createMagnificationModeDialog() {
         mMagnificationModesListView = AccessibilityDialogUtils.createSingleChoiceListView(
                 mContext, mModeInfos, this::onMagnificationModeSelected);
 
         final View headerView = LayoutInflater.from(mContext).inflate(
-                R.layout.accessibility_magnification_mode_header, mMagnificationModesListView,
+                R.layout.accessibility_magnification_mode_header,
-                false);
+                getMagnificationModesListView(), /* attachToRoot= */false);
-        mMagnificationModesListView.addHeaderView(headerView, /* data= */ null, /* isSelectable= */
+        getMagnificationModesListView().addHeaderView(headerView, /* data= */null,
-                false);
+                /* isSelectable= */false);
 
-        mMagnificationModesListView.setItemChecked(computeSelectionIndex(), true);
+        getMagnificationModesListView().setItemChecked(computeSelectionIndex(), /* value= */true);
         final CharSequence title = mContext.getString(
                 R.string.accessibility_magnification_mode_dialog_title);
         final CharSequence positiveBtnText = mContext.getString(R.string.save);
         final CharSequence negativeBtnText = mContext.getString(R.string.cancel);
 
         return AccessibilityDialogUtils.createCustomDialog(mContext, title,
-                mMagnificationModesListView,
+                getMagnificationModesListView(), positiveBtnText,
-                positiveBtnText, this::onMagnificationModeDialogPositiveButtonClicked,
+                this::onMagnificationModeDialogPositiveButtonClicked,
-                negativeBtnText, /* negativeListener= */ null);
+                negativeBtnText, /* negativeListener= */null);
     }
 
     @VisibleForTesting
-    void onMagnificationModeDialogPositiveButtonClicked(DialogInterface dialogInterface,
+    void onMagnificationModeDialogPositiveButtonClicked(@NonNull DialogInterface dialogInterface,
             int which) {
-        final int selectedIndex = mMagnificationModesListView.getCheckedItemPosition();
+        final int selectedIndex = getMagnificationModesListView().getCheckedItemPosition();
         if (selectedIndex == AdapterView.INVALID_POSITION) {
-            Log.w(TAG, "invalid index");
+            Log.w(TAG, "Selected positive button with INVALID_POSITION index");
             return;
         }
 
-        mModeCache = ((MagnificationModeInfo) mMagnificationModesListView.getItemAtPosition(
+        mModeCache = ((MagnificationModeInfo) getMagnificationModesListView().getItemAtPosition(
-                        selectedIndex)).mMagnificationMode;
+                selectedIndex)).mMagnificationMode;
 
         // Do not save mode until user clicks positive button in triple tap warning dialog.
         if (isTripleTapEnabled(mContext) && mModeCache != MagnificationMode.FULLSCREEN) {
-            mDialogHelper.showDialog(DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
+            Preconditions.checkNotNull(mDialogHelper).showDialog(
+                    DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
         } else { // Save mode (capabilities) value, don't need to show dialog to confirm.
             updateCapabilitiesAndSummary(mModeCache);
         }
@@ -211,15 +217,14 @@ public class MagnificationModePreferenceController extends BasePreferenceControl
     private void updateCapabilitiesAndSummary(@MagnificationMode int mode) {
         mModeCache = mode;
         MagnificationCapabilities.setCapabilities(mContext, mModeCache);
-        mModePreference.setSummary(
+        Preconditions.checkNotNull(mModePreference).setSummary(
                 MagnificationCapabilities.getSummary(mContext, mModeCache));
     }
 
-    private void onMagnificationModeSelected(AdapterView<?> parent, View view, int position,
+    private void onMagnificationModeSelected(@NonNull AdapterView<?> parent, @NonNull View view,
-            long id) {
+            int position, long id) {
         final MagnificationModeInfo modeInfo =
-                (MagnificationModeInfo) mMagnificationModesListView.getItemAtPosition(
+                (MagnificationModeInfo) getMagnificationModesListView().getItemAtPosition(position);
-                        position);
         if (modeInfo.mMagnificationMode == mModeCache) {
             return;
         }
@@ -230,20 +235,22 @@ public class MagnificationModePreferenceController extends BasePreferenceControl
         final int modesSize = mModeInfos.size();
         for (int i = 0; i < modesSize; i++) {
             if (mModeInfos.get(i).mMagnificationMode == mModeCache) {
-                return i + mMagnificationModesListView.getHeaderViewsCount();
+                return i + getMagnificationModesListView().getHeaderViewsCount();
             }
         }
-        Log.w(TAG, "computeSelectionIndex failed");
+        Log.w(TAG, "Can not find matching mode in mModeInfos");
         return 0;
     }
 
     @VisibleForTesting
-    static boolean isTripleTapEnabled(Context context) {
+    static boolean isTripleTapEnabled(@NonNull Context context) {
         return Settings.Secure.getInt(context.getContentResolver(),
                 Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_ENABLED, OFF) == ON;
     }
 
+    @NonNull
     private Dialog createMagnificationTripleTapWarningDialog() {
+        @SuppressWarnings({"InflateParams"})
         final View contentView = LayoutInflater.from(mContext).inflate(
                 R.layout.magnification_triple_tap_warning_dialog, /* root= */ null);
         final CharSequence title = mContext.getString(
@@ -263,12 +270,13 @@ public class MagnificationModePreferenceController extends BasePreferenceControl
         return dialog;
     }
 
-    private void updateLinkInTripleTapWarningDialog(Dialog dialog, View contentView) {
+    private void updateLinkInTripleTapWarningDialog(@NonNull Dialog dialog,
+            @NonNull View contentView) {
         final TextView messageView = contentView.findViewById(R.id.message);
         // TODO(b/225682559): Need to remove performClick() after refactoring accessibility dialog.
         final View.OnClickListener linkListener = view -> {
             updateCapabilitiesAndSummary(mModeCache);
-            mLinkPreference.performClick();
+            Preconditions.checkNotNull(mLinkPreference).performClick();
             dialog.dismiss();
         };
         final AnnotationSpan.LinkInfo linkInfo = new AnnotationSpan.LinkInfo(
@@ -285,25 +293,18 @@ public class MagnificationModePreferenceController extends BasePreferenceControl
 
     @VisibleForTesting
     void onMagnificationTripleTapWarningDialogNegativeButtonClicked(
-            DialogInterface dialogInterface, int which) {
+            @NonNull DialogInterface dialogInterface, int which) {
         mModeCache = MagnificationCapabilities.getCapabilities(mContext);
-        mDialogHelper.showDialog(DIALOG_MAGNIFICATION_MODE);
+        Preconditions.checkNotNull(mDialogHelper).showDialog(
+                DialogEnums.DIALOG_MAGNIFICATION_MODE);
     }
 
     @VisibleForTesting
     void onMagnificationTripleTapWarningDialogPositiveButtonClicked(
-            DialogInterface dialogInterface, int which) {
+            @NonNull DialogInterface dialogInterface, int which) {
         updateCapabilitiesAndSummary(mModeCache);
     }
 
-    /**
-     * An interface to help the delegate to show the dialog. It will be injected to the delegate.
-     */
-    interface DialogHelper extends DialogCreatable {
-        void showDialog(int dialogId);
-        void setDialogDelegate(DialogCreatable delegate);
-    }
-
     @VisibleForTesting
     static class MagnificationModeInfo extends ItemInfoArrayAdapter.ItemInfo {
         @MagnificationMode

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

@@ -19,7 +19,6 @@ package com.android.settings.accessibility;
 import static com.android.internal.accessibility.AccessibilityShortcutController.MAGNIFICATION_COMPONENT_NAME;
 import static com.android.internal.accessibility.AccessibilityShortcutController.MAGNIFICATION_CONTROLLER_NAME;
 import static com.android.internal.accessibility.common.ShortcutConstants.UserShortcutType.DEFAULT;
-import static com.android.settings.accessibility.AccessibilityDialogUtils.DialogEnums;
 import static com.android.settings.accessibility.AccessibilityUtil.State.OFF;
 import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
 import static com.android.settings.accessibility.AccessibilityUtil.getShortcutSummaryList;
@@ -42,8 +41,10 @@ import android.view.ViewGroup;
 import android.view.accessibility.AccessibilityManager;
 import android.view.accessibility.AccessibilityManager.TouchExplorationStateChangeListener;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
+import androidx.core.util.Preconditions;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceCategory;
 import androidx.preference.SwitchPreferenceCompat;
@@ -53,6 +54,7 @@ import com.android.internal.annotations.VisibleForTesting;
 import com.android.server.accessibility.Flags;
 import com.android.settings.DialogCreatable;
 import com.android.settings.R;
+import com.android.settings.accessibility.AccessibilityDialogUtils.DialogEnums;
 import com.android.settings.accessibility.shortcuts.EditShortcutsPreferenceFragment;
 import com.android.settings.search.BaseSearchIndexProvider;
 import com.android.settingslib.core.AbstractPreferenceController;
@@ -74,10 +76,10 @@ import java.util.stream.Stream;
  */
 @SearchIndexable(forTarget = SearchIndexable.ALL & ~SearchIndexable.ARC)
 public class ToggleScreenMagnificationPreferenceFragment extends
-        ToggleFeaturePreferenceFragment implements
+        ToggleFeaturePreferenceFragment implements DialogHelper {
-        MagnificationModePreferenceController.DialogHelper {
 
-    private static final String TAG = "ToggleScreenMagnificationPreferenceFragment";
+    private static final String TAG =
+            ToggleScreenMagnificationPreferenceFragment.class.getSimpleName();
     @VisibleForTesting
     static final String KEY_MAGNIFICATION_SHORTCUT_PREFERENCE = "magnification_shortcut_preference";
     private static final char COMPONENT_NAME_SEPARATOR = ':';
@@ -86,23 +88,30 @@ public class ToggleScreenMagnificationPreferenceFragment extends
 
     // TODO(b/147021230): Move duplicated functions with android/internal/accessibility into util.
     private TouchExplorationStateChangeListener mTouchExplorationStateChangeListener;
-    private DialogCreatable mDialogDelegate;
+    @Nullable
+    private DialogCreatable mMagnificationModeDialogDelegate;
 
     @Nullable
     MagnificationOneFingerPanningPreferenceController mOneFingerPanningPreferenceController;
 
     private boolean mInSetupWizard;
 
+    @VisibleForTesting
+    public void setMagnificationModeDialogDelegate(@NonNull DialogCreatable delegate) {
+        mMagnificationModeDialogDelegate = delegate;
+    }
+
     @Override
-    public void onCreate(Bundle savedInstanceState) {
+    public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         getActivity().setTitle(R.string.accessibility_screen_magnification_title);
         mInSetupWizard = WizardManagerHelper.isAnySetupWizard(getIntent());
     }
 
+    @NonNull
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
-            Bundle savedInstanceState) {
+            @NonNull Bundle savedInstanceState) {
         mFeatureName = getString(R.string.accessibility_screen_magnification_title);
         mImageUri = new Uri.Builder().scheme(ContentResolver.SCHEME_ANDROID_RESOURCE)
                 .authority(getPrefContext().getPackageName())
@@ -161,15 +170,14 @@ public class ToggleScreenMagnificationPreferenceFragment extends
         super.onPause();
     }
 
+    @NonNull
     @Override
     public Dialog onCreateDialog(int dialogId) {
-        if (mDialogDelegate != null) {
-            mDialog = mDialogDelegate.onCreateDialog(dialogId);
-            if (mDialog != null) {
-                return mDialog;
-            }
-        }
         switch (dialogId) {
+            case DialogEnums.DIALOG_MAGNIFICATION_MODE:
+            case DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING:
+                return Preconditions.checkNotNull(mMagnificationModeDialogDelegate)
+                        .onCreateDialog(dialogId);
             case DialogEnums.GESTURE_NAVIGATION_TUTORIAL:
                 return AccessibilityShortcutsTutorial
                         .showAccessibilityGestureTutorialDialog(getPrefContext());
@@ -238,9 +246,10 @@ public class ToggleScreenMagnificationPreferenceFragment extends
         generalCategory.addPreference(mSettingsPreference);
 
         final MagnificationModePreferenceController magnificationModePreferenceController =
-                new MagnificationModePreferenceController(getContext(),
+                new MagnificationModePreferenceController(Preconditions.checkNotNull(getContext()),
                         MagnificationModePreferenceController.PREF_KEY);
-        magnificationModePreferenceController.setDialogHelper(this);
+        magnificationModePreferenceController.setDialogHelper(/* dialogHelper= */this);
+        mMagnificationModeDialogDelegate = magnificationModePreferenceController;
         getSettingsLifecycle().addObserver(magnificationModePreferenceController);
         magnificationModePreferenceController.displayPreference(getPreferenceScreen());
         addPreferenceController(magnificationModePreferenceController);
@@ -388,11 +397,6 @@ public class ToggleScreenMagnificationPreferenceFragment extends
         super.showDialog(dialogId);
     }
 
-    @Override
-    public void setDialogDelegate(DialogCreatable delegate) {
-        mDialogDelegate = delegate;
-    }
-
     @Override
     protected void registerKeysToObserverCallback(
             AccessibilitySettingsContentObserver contentObserver) {
@@ -470,14 +474,11 @@ public class ToggleScreenMagnificationPreferenceFragment extends
 
     @Override
     public int getDialogMetricsCategory(int dialogId) {
-        if (mDialogDelegate != null) {
-            final int category = mDialogDelegate.getDialogMetricsCategory(dialogId);
-            if (category != 0) {
-                return category;
-            }
-        }
-
         switch (dialogId) {
+            case DialogEnums.DIALOG_MAGNIFICATION_MODE:
+            case DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING:
+                return Preconditions.checkNotNull(mMagnificationModeDialogDelegate)
+                        .getDialogMetricsCategory(dialogId);
             case DialogEnums.GESTURE_NAVIGATION_TUTORIAL:
                 return SettingsEnums.DIALOG_TOGGLE_SCREEN_MAGNIFICATION_GESTURE_NAVIGATION;
             case DialogEnums.ACCESSIBILITY_BUTTON_TUTORIAL:
@@ -514,7 +515,7 @@ public class ToggleScreenMagnificationPreferenceFragment extends
     }
 
     @Override
-    public void onToggleClicked(ShortcutPreference preference) {
+    public void onToggleClicked(@NonNull ShortcutPreference preference) {
         final int shortcutTypes = getUserPreferredShortcutTypes();
         getPrefContext().getSystemService(AccessibilityManager.class).enableShortcutsForTargets(
                 preference.isChecked(), shortcutTypes,
@@ -527,7 +528,7 @@ public class ToggleScreenMagnificationPreferenceFragment extends
     }
 
     @Override
-    public void onSettingsClicked(ShortcutPreference preference) {
+    public void onSettingsClicked(@NonNull ShortcutPreference preference) {
         EditShortcutsPreferenceFragment.showEditShortcutScreen(
                 requireContext(),
                 getMetricsCategory(),
@@ -581,7 +582,8 @@ public class ToggleScreenMagnificationPreferenceFragment extends
      *
      * @param context The current context.
      */
-    public static CharSequence getServiceSummary(Context context) {
+    @NonNull
+    public static CharSequence getServiceSummary(@NonNull Context context) {
         // Get the user shortcut type from settings provider.
         final int userShortcutType = ShortcutUtils.getEnabledShortcutTypes(
                 context, MAGNIFICATION_CONTROLLER_NAME);
@@ -604,8 +606,9 @@ public class ToggleScreenMagnificationPreferenceFragment extends
     public static final Indexable.SearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
             new BaseSearchIndexProvider() {
                 // LINT.IfChange(search_data)
+                @NonNull
                 @Override
-                public List<SearchIndexableRaw> getRawDataToIndex(Context context,
+                public List<SearchIndexableRaw> getRawDataToIndex(@NonNull Context context,
                         boolean enabled) {
                     final List<SearchIndexableRaw> rawData =
                             super.getRawDataToIndex(context, enabled);
@@ -628,8 +631,9 @@ public class ToggleScreenMagnificationPreferenceFragment extends
                     return rawData;
                 }
 
+                @NonNull
                 @Override
-                public List<String> getNonIndexableKeys(Context context) {
+                public List<String> getNonIndexableKeys(@NonNull Context context) {
                     final List<String> niks = super.getNonIndexableKeys(context);
 
                     if (!com.android.settings.accessibility.Flags.fixA11ySettingsSearch()) {

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

@@ -17,8 +17,6 @@
 package com.android.settings.accessibility;
 
 import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
-import static com.android.settings.accessibility.MagnificationCapabilities.MagnificationMode;
-import static com.android.settings.accessibility.MagnificationModePreferenceController.MagnificationModeInfo;
 
 import static com.google.common.truth.Truth.assertThat;
 
@@ -37,6 +35,7 @@ import android.widget.AdapterView;
 import android.widget.ListView;
 import android.widget.TextView;
 
+import androidx.annotation.NonNull;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceManager;
 import androidx.preference.PreferenceScreen;
@@ -44,6 +43,9 @@ import androidx.test.core.app.ApplicationProvider;
 
 import com.android.settings.DialogCreatable;
 import com.android.settings.R;
+import com.android.settings.accessibility.AccessibilityDialogUtils.DialogEnums;
+import com.android.settings.accessibility.MagnificationCapabilities.MagnificationMode;
+import com.android.settings.accessibility.MagnificationModePreferenceController.MagnificationModeInfo;
 import com.android.settings.utils.AnnotationSpan;
 
 import org.junit.Before;
@@ -82,6 +84,8 @@ public class MagnificationModePreferenceControllerTest {
         mScreen.addPreference(mModePreference);
         MagnificationCapabilities.setCapabilities(mContext, MAGNIFICATION_MODE_DEFAULT);
         mController = new MagnificationModePreferenceController(mContext, PREF_KEY);
+        mController.setDialogHelper(mDialogHelper);
+        mDialogHelper.setDialogDelegate(mController);
         showPreferenceOnTheScreen(null);
     }
 
@@ -107,7 +111,7 @@ public class MagnificationModePreferenceControllerTest {
         performItemClickWith(MagnificationMode.WINDOW);
 
         reshowPreferenceOnTheScreen();
-        mDialogHelper.showDialog(MagnificationModePreferenceController.DIALOG_MAGNIFICATION_MODE);
+        mDialogHelper.showDialog(DialogEnums.DIALOG_MAGNIFICATION_MODE);
 
         assertThat(getCheckedModeFromDialog()).isEqualTo(
                 MagnificationMode.WINDOW);
@@ -123,7 +127,7 @@ public class MagnificationModePreferenceControllerTest {
                 DialogInterface.BUTTON_POSITIVE);
 
         verify(mDialogHelper, never()).showDialog(
-                MagnificationModePreferenceController.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
+                DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
     }
 
     @Test
@@ -135,8 +139,7 @@ public class MagnificationModePreferenceControllerTest {
         mController.onMagnificationModeDialogPositiveButtonClicked(mDialogHelper.getDialog(),
                 DialogInterface.BUTTON_POSITIVE);
 
-        verify(mDialogHelper).showDialog(
+        verify(mDialogHelper).showDialog(DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
-                MagnificationModePreferenceController.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
     }
 
     @Test
@@ -148,20 +151,17 @@ public class MagnificationModePreferenceControllerTest {
         mController.onMagnificationModeDialogPositiveButtonClicked(mDialogHelper.getDialog(),
                 DialogInterface.BUTTON_POSITIVE);
 
-        verify(mDialogHelper).showDialog(
+        verify(mDialogHelper).showDialog(DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
-                MagnificationModePreferenceController.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
     }
 
     @Test
     public void onTripleTapWarningDialogNegativeButtonClicked_showModeDialog() {
-        mDialogHelper.showDialog(
+        mDialogHelper.showDialog(DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
-                MagnificationModePreferenceController.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
 
         mController.onMagnificationTripleTapWarningDialogNegativeButtonClicked(
                 mDialogHelper.getDialog(), DialogInterface.BUTTON_NEGATIVE);
 
-        verify(mDialogHelper).showDialog(
+        verify(mDialogHelper).showDialog(DialogEnums.DIALOG_MAGNIFICATION_MODE);
-                MagnificationModePreferenceController.DIALOG_MAGNIFICATION_MODE);
     }
 
     @Test
@@ -182,8 +182,7 @@ public class MagnificationModePreferenceControllerTest {
 
     @Test
     public void checkSpansInTripleTapWarningDialog_existAnnotationSpan() {
-        mDialogHelper.showDialog(
+        mDialogHelper.showDialog(DialogEnums.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
-                MagnificationModePreferenceController.DIALOG_MAGNIFICATION_TRIPLE_TAP_WARNING);
         final View contentView = mDialogHelper.getDialog().findViewById(android.R.id.content);
         final TextView messageView = contentView.findViewById(R.id.message);
         final CharSequence textInTripleTapWarningDialog = messageView.getText();
@@ -256,13 +255,11 @@ public class MagnificationModePreferenceControllerTest {
     }
 
     private void showPreferenceOnTheScreen(Bundle savedInstanceState) {
-        mController.setDialogHelper(mDialogHelper);
         mController.onCreate(savedInstanceState);
         mController.displayPreference(mScreen);
     }
 
-    private static class TestDialogHelper implements DialogCreatable,
+    private static class TestDialogHelper implements DialogCreatable, DialogHelper {
-            MagnificationModePreferenceController.DialogHelper {
         private DialogCreatable mDialogDelegate;
         private Dialog mDialog;
 
@@ -271,11 +268,11 @@ public class MagnificationModePreferenceControllerTest {
             mDialog = onCreateDialog(dialogId);
         }
 
-        @Override
+        public void setDialogDelegate(@NonNull DialogCreatable delegate) {
-        public void setDialogDelegate(DialogCreatable delegate) {
             mDialogDelegate = delegate;
         }
 
+        @NonNull
         @Override
         public Dialog onCreateDialog(int dialogId) {
             return mDialogDelegate.onCreateDialog(dialogId);

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

@@ -64,6 +64,8 @@ import com.android.server.accessibility.Flags;
 import com.android.settings.DialogCreatable;
 import com.android.settings.R;
 import com.android.settings.SettingsActivity;
+import com.android.settings.accessibility.AccessibilityDialogUtils.DialogEnums;
+import com.android.settings.accessibility.MagnificationCapabilities.MagnificationMode;
 import com.android.settings.testutils.shadow.ShadowAccessibilityManager;
 import com.android.settings.testutils.shadow.ShadowDeviceConfig;
 import com.android.settings.testutils.shadow.ShadowStorageManager;
@@ -550,7 +552,8 @@ public class ToggleScreenMagnificationPreferenceFragmentTest {
         ToggleScreenMagnificationPreferenceFragment fragment = mFragController.create(
                 R.id.main_content, /* bundle= */ null).start().resume().get();
 
-        DialogCreatable dialogDelegate = ReflectionHelpers.getField(fragment, "mDialogDelegate");
+        DialogCreatable dialogDelegate = ReflectionHelpers.getField(fragment,
+                "mMagnificationModeDialogDelegate");
         List<LifecycleObserver> lifecycleObservers = ReflectionHelpers.getField(
                 fragment.getSettingsLifecycle(), "mObservers");
         assertThat(dialogDelegate).isInstanceOf(MagnificationModePreferenceController.class);
@@ -592,19 +595,19 @@ public class ToggleScreenMagnificationPreferenceFragmentTest {
     }
 
     @Test
-    public void onCreateDialog_setDialogDelegate_invokeDialogDelegate() {
+    public void onCreateDialog_setMagnificationModeDialogDelegate_invokeDialogDelegate() {
         ToggleScreenMagnificationPreferenceFragment fragment =
                 mFragController.create(
                         R.id.main_content, /* bundle= */ null).start().resume().get();
         final DialogCreatable dialogDelegate = mock(DialogCreatable.class, RETURNS_DEEP_STUBS);
-        when(dialogDelegate.getDialogMetricsCategory(anyInt())).thenReturn(1);
+        final int dialogId = DialogEnums.DIALOG_MAGNIFICATION_MODE;
-        fragment.setDialogDelegate(dialogDelegate);
+        when(dialogDelegate.getDialogMetricsCategory(anyInt())).thenReturn(dialogId);
+        fragment.setMagnificationModeDialogDelegate(dialogDelegate);
 
-        fragment.onCreateDialog(1);
+        fragment.onCreateDialog(dialogId);
-        fragment.getDialogMetricsCategory(1);
+        fragment.getDialogMetricsCategory(dialogId);
-
+        verify(dialogDelegate).onCreateDialog(dialogId);
-        verify(dialogDelegate).onCreateDialog(1);
+        verify(dialogDelegate).getDialogMetricsCategory(dialogId);
-        verify(dialogDelegate).getDialogMetricsCategory(1);
     }
 
     @Test