Create settings for window magnification (2/n)

Provide a setting for new Magnify area feature and joystick controller

Bug: 146019459
Bug: 146473544
Test: make RunSettingsRoboTests ROBOTEST_FILTER=MagnificationModePreferenceControllerTest
Test: make RunSettingsRoboTests ROBOTEST_FILTER=MagnificationWindowControlPreferenceControllerTest
Test: make RunSettingsRoboTests2
Change-Id: Ia32fa073c59ad304e9ef9eb530ba37dd24c2f2f6

res/layout/accessibility_edit_magnification_mode.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (C) 2019 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
+  -->
+
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:scrollbarStyle="outsideOverlay">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:paddingEnd="24dp"
+        android:paddingStart="24dp">
+
+        <TextView
+            style="@style/AccessibilityDialogDescription"
+            android:text="@string/accessibility_magnification_area_settings_message" />
+
+        <include
+            android:id="@+id/magnify_full_screen"
+            layout="@layout/accessibility_edit_shortcut_component" />
+
+        <include
+            android:id="@+id/magnify_window_screen"
+            layout="@layout/accessibility_edit_shortcut_component" />
+
+    </LinearLayout>
+
+</ScrollView>

res/layout/accessibility_edit_shortcut_component.xml

@@ -19,12 +19,14 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:orientation="vertical">
+    android:orientation="vertical"
+    android:paddingBottom="16dp">
 
     <CheckBox
         android:id="@+id/checkbox"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"/>
+        android:layout_height="wrap_content"
+        android:saveEnabled="false"/>
 
     <TextView
         android:id="@+id/summary"

res/values/arrays.xml

@@ -1014,8 +1014,25 @@
         <item>\?</item>
     </string-array>
 
+    <!-- Summary for magnification adjustment modes for accessibility -->
+    <string-array name="magnification_mode_summaries" translatable="false">
+        <item>@string/accessibility_magnification_area_settings_full_screen_summary</item>
+        <item>@string/accessibility_magnification_area_settings_window_screen_summary</item>
+        <item>@string/accessibility_magnification_area_settings_all_summary</item>
+    </string-array>
+
+    <!-- Values for magnification adjustment modes for accessibility -->
+    <integer-array name="magnification_mode_values" translatable="false">
+        <!-- Full screen -->
+        <item>1</item>
+        <!-- Window screen -->
+        <item>2</item>
+        <!-- Full screen and window screen. -->
+        <item>3</item>
+    </integer-array>
+
     <!-- Summary for color space adjustment modes for accessibility -->
-    <string-array name="daltonizer_mode_summary" translatable="false">
+    <string-array name="daltonizer_mode_summaries" translatable="false">
         <item>@string/daltonizer_mode_deuteranomaly</item>
         <item>@string/daltonizer_mode_protanomaly</item>
         <item>@string/daltonizer_mode_tritanomaly</item>

res/values/strings.xml

@@ -4755,6 +4755,26 @@
     <string name="accessibility_captioning_title">Caption preferences</string>
     <!-- Title for the accessibility preference screen to enable screen magnification. [CHAR LIMIT=35] -->
     <string name="accessibility_screen_magnification_title">Magnification</string>
+    <!-- Title for the accessibility preference screen to edit magnification area. [CHAR LIMIT=35] -->
+    <string name="accessibility_magnification_mode_title">Magnification area</string>
+    <!-- Message for the accessibility preference screen to edit magnification area dialog. [CHAR LIMIT=none] -->
+    <string name="accessibility_magnification_area_settings_message">Choose the magnification area(s) you want to use when magnifying the screen</string>
+    <!-- Summary for the accessibility preference screen to edit full screen. [CHAR LIMIT=none] -->
+    <string name="accessibility_magnification_area_settings_full_screen_summary">Full screen</string>
+    <!-- Summary for the accessibility preference screen to edit window screen. [CHAR LIMIT=none] -->
+    <string name="accessibility_magnification_area_settings_window_screen_summary">Part of screen</string>
+    <!-- Summary for the accessibility preference screen to edit entire screen. [CHAR LIMIT=none] -->
+    <string name="accessibility_magnification_area_settings_all_summary">Full screen &amp; part of screen</string>
+    <!-- Message for the accessibility preference screen to edit entire screen. [CHAR LIMIT=none] -->
+    <string name="accessibility_magnification_area_settings_full_screen">Magnify entire screen</string>
+    <!-- Message for the accessibility preference screen to edit part of screen. [CHAR LIMIT=none] -->
+    <string name="accessibility_magnification_area_settings_window_screen">Magnify part of screen</string>
+    <!-- Title for the accessibility preference screen to show move controller. [CHAR LIMIT=35] -->
+    <string name="accessibility_magnification_window_control_switch_title">Show move controller</string>
+    <!-- Summary for the accessibility preference screen to show move controller. [CHAR LIMIT=none] -->
+    <string name="accessibility_magnification_window_control_switch_summary">Show a joystick-like controller to move the magnification area</string>
+    <!-- Title for the accessibility preference screen to enable screen magnification settings. [CHAR LIMIT=35] -->
+    <string name="accessibility_magnification_service_settings_title">Magnify settings</string>
     <!-- Title for the accessibility preference screen to enable triple-tap gesture screen magnification. [CHAR LIMIT=35] -->
     <string name="accessibility_screen_magnification_gestures_title">Magnify with triple-tap</string>
     <!-- Title for the accessibility preference screen to enable navigation bar screen magnification. [CHAR LIMIT=35] -->

res/xml/accessibility_magnification_service_settings.xml

@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (C) 2019 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.
+  -->
+
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:settings="http://schemas.android.com/apk/res-auto"
+    android:key="magnification_mode_screen"
+    android:persistent="false"
+    android:title="@string/accessibility_magnification_service_settings_title">
+
+    <Preference
+        android:key="magnification_mode"
+        android:persistent="false"
+        android:title="@string/accessibility_magnification_mode_title"
+        settings:controller="com.android.settings.accessibility.MagnificationModePreferenceController" />
+
+    <SwitchPreference
+        android:key="magnification_window_control_switch"
+        android:persistent="false"
+        android:summary="@string/accessibility_magnification_window_control_switch_summary"
+        android:title="@string/accessibility_magnification_window_control_switch_title"
+        settings:controller="com.android.settings.accessibility.MagnificationWindowControlPreferenceController" />
+</PreferenceScreen>

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

@@ -24,6 +24,7 @@ import android.content.res.TypedArray;
 import android.graphics.drawable.Drawable;
 import android.text.Spannable;
 import android.text.SpannableString;
+import android.text.TextUtils;
 import android.text.style.ImageSpan;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -53,13 +54,15 @@ public class AccessibilityEditDialogUtils {
      */
     @Retention(RetentionPolicy.SOURCE)
     @IntDef({
-            DialogType.EDIT_SHORTCUT_GENERIC,
+         DialogType.EDIT_SHORTCUT_GENERIC,
-            DialogType.EDIT_SHORTCUT_MAGNIFICATION,
+         DialogType.EDIT_SHORTCUT_MAGNIFICATION,
+         DialogType.EDIT_MAGNIFICATION_MODE,
     })
 
     private @interface DialogType {
         int EDIT_SHORTCUT_GENERIC = 0;
         int EDIT_SHORTCUT_MAGNIFICATION = 1;
+        int EDIT_MAGNIFICATION_MODE = 2;
     }
 
     /**
@@ -96,6 +99,23 @@ public class AccessibilityEditDialogUtils {
         return alertDialog;
     }
 
+    /**
+     * Method to show the magnification mode dialog in Magnification.
+     *
+     * @param context A valid context
+     * @param dialogTitle The title of magnify mode dialog
+     * @param listener The listener to determine the action of magnify mode dialog
+     * @return A magnification mode dialog in Magnification
+     */
+    public static AlertDialog showMagnificationModeDialog(Context context,
+            CharSequence dialogTitle, DialogInterface.OnClickListener listener) {
+        final AlertDialog alertDialog = createDialog(context,
+                DialogType.EDIT_MAGNIFICATION_MODE, dialogTitle, listener);
+        alertDialog.show();
+
+        return alertDialog;
+    }
+
     private static AlertDialog createDialog(Context context, int dialogType,
             CharSequence dialogTitle, DialogInterface.OnClickListener listener) {
 
@@ -138,6 +158,12 @@ public class AccessibilityEditDialogUtils {
                 initMagnifyShortcut(context, contentView);
                 initAdvancedWidget(contentView);
                 break;
+            case DialogType.EDIT_MAGNIFICATION_MODE:
+                contentView = inflater.inflate(
+                        R.layout.accessibility_edit_magnification_mode, null);
+                initMagnifyFullScreen(context, contentView);
+                initMagnifyWindowScreen(context, contentView);
+                break;
             default:
                 throw new IllegalArgumentException();
         }
@@ -145,12 +171,37 @@ public class AccessibilityEditDialogUtils {
         return contentView;
     }
 
+    private static void initMagnifyFullScreen(Context context, View view) {
+        final View dialogView = view.findViewById(R.id.magnify_full_screen);
+        final String title = context.getString(
+                R.string.accessibility_magnification_area_settings_full_screen);
+        // TODO(b/146019459): Use vector drawable instead of temporal png file to avoid distorted.
+        setupShortcutWidget(dialogView, title, R.drawable.accessibility_magnification_full_screen);
+    }
+
+    private static void initMagnifyWindowScreen(Context context, View view) {
+        final View dialogView = view.findViewById(R.id.magnify_window_screen);
+        final String title = context.getString(
+                R.string.accessibility_magnification_area_settings_window_screen);
+        // TODO(b/146019459): Use vector drawable instead of temporal png file to avoid distorted.
+        setupShortcutWidget(dialogView, title,
+                R.drawable.accessibility_magnification_window_screen);
+    }
+
+    private static void setupShortcutWidget(View view, CharSequence titleText, int imageResId) {
+        setupShortcutWidget(view, titleText, null, imageResId);
+    }
+
     private static void setupShortcutWidget(View view, CharSequence titleText,
             CharSequence summaryText, int imageResId) {
         final CheckBox checkBox = view.findViewById(R.id.checkbox);
         checkBox.setText(titleText);
         final TextView summary = view.findViewById(R.id.summary);
-        summary.setText(summaryText);
+        if (TextUtils.isEmpty(summaryText)) {
+            summary.setVisibility(View.GONE);
+        } else {
+            summary.setText(summaryText);
+        }
         final ImageView image = view.findViewById(R.id.image);
         image.setImageResource(imageResId);
     }

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

@@ -42,15 +42,15 @@ public class DaltonizerPreferenceController extends BasePreferenceController {
 
     @Override
     public CharSequence getSummary() {
-        final String[] daltonizerSummarys = mContext.getResources().getStringArray(
+        final String[] daltonizerSummaries = mContext.getResources().getStringArray(
-                R.array.daltonizer_mode_summary);
+                R.array.daltonizer_mode_summaries);
         final int[] daltonizerValues = mContext.getResources().getIntArray(
                 R.array.daltonizer_type_values);
         final int timeoutValue =
                 DaltonizerRadioButtonPreferenceController.getSecureAccessibilityDaltonizerValue(
                         mContext.getContentResolver(), DALTONIZER_TYPE);
         final int idx = Ints.indexOf(daltonizerValues, timeoutValue);
-        final String serviceSummary = daltonizerSummarys[idx == -1 ? 0 : idx];
+        final String serviceSummary = daltonizerSummaries[idx == -1 ? 0 : idx];
 
         final CharSequence serviceState = AccessibilityUtil.getSummary(mContext,
                 DALTONIZER_ENABLED);

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

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2019 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 com.android.settings.core.BasePreferenceController;
+
+/** Controller that shows the magnification area mode summary. */
+public class MagnificationModePreferenceController extends BasePreferenceController {
+
+    public MagnificationModePreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+
+    @Override
+    public CharSequence getSummary() {
+        return MagnificationSettingsFragment.getMagnificationCapabilitiesSummary(
+                mContext);
+    }
+}

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

@@ -0,0 +1,234 @@
+/*
+ * Copyright (C) 2019 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.app.Dialog;
+import android.app.settings.SettingsEnums;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.os.Bundle;
+import android.provider.Settings;
+import android.view.View;
+import android.widget.CheckBox;
+
+import androidx.annotation.IntDef;
+import androidx.appcompat.app.AlertDialog;
+import androidx.preference.Preference;
+
+import com.android.settings.R;
+import com.android.settings.dashboard.DashboardFragment;
+import com.android.settings.search.BaseSearchIndexProvider;
+import com.android.settingslib.search.SearchIndexable;
+
+import com.google.common.primitives.Ints;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/** Settings page for magnification. */
+@SearchIndexable
+public class MagnificationSettingsFragment extends DashboardFragment {
+
+    private static final String TAG = "MagnificationSettingsFragment";
+    private static final String PREF_KEY_MODE = "magnification_mode";
+    // TODO(b/146019459): Use magnification_capability.
+    private static final String KEY_CAPABILITY = Settings.System.MASTER_MONO;
+    private static final int DIALOG_MAGNIFICATION_CAPABILITY = 1;
+    private static final String EXTRA_CAPABILITY = "capability";
+    private Preference mModePreference;
+    private int mCapabilities = MagnifyMode.NONE;
+    private CheckBox mMagnifyFullScreenCheckBox;
+    private CheckBox mMagnifyWindowCheckBox;
+
+    static String getMagnificationCapabilitiesSummary(Context context) {
+        final String[] magnificationModeSummaries = context.getResources().getStringArray(
+                R.array.magnification_mode_summaries);
+        final int[] magnificationModeValues = context.getResources().getIntArray(
+                R.array.magnification_mode_values);
+        final int capabilities = MagnificationSettingsFragment.getMagnificationCapabilities(
+                context);
+
+        final int idx = Ints.indexOf(magnificationModeValues, capabilities);
+        return magnificationModeSummaries[idx == -1 ? 0 : idx];
+    }
+
+    private static int getMagnificationCapabilities(Context context) {
+        return getSecureIntValue(context, KEY_CAPABILITY, MagnifyMode.FULLSCREEN);
+    }
+
+    private static int getSecureIntValue(Context context, String key, int defaultValue) {
+        return Settings.Secure.getIntForUser(
+                context.getContentResolver(),
+                key, defaultValue, context.getContentResolver().getUserId());
+    }
+
+    @Override
+    public int getMetricsCategory() {
+        return SettingsEnums.ACCESSIBILITY_MAGNIFICATION_SETTINGS;
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        outState.putInt(EXTRA_CAPABILITY, mCapabilities);
+        super.onSaveInstanceState(outState);
+    }
+
+    @Override
+    public void onActivityCreated(Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+        if (savedInstanceState != null) {
+            mCapabilities = savedInstanceState.getInt(EXTRA_CAPABILITY, MagnifyMode.NONE);
+        }
+        if (mCapabilities == MagnifyMode.NONE) {
+            mCapabilities = getMagnificationCapabilities(getPrefContext());
+        }
+    }
+
+    @Override
+    public int getDialogMetricsCategory(int dialogId) {
+        switch (dialogId) {
+            case DIALOG_MAGNIFICATION_CAPABILITY:
+                return SettingsEnums.DIALOG_MAGNIFICATION_CAPABILITY;
+            default:
+                return 0;
+        }
+    }
+
+    @Override
+    protected String getLogTag() {
+        return TAG;
+    }
+
+    @Override
+    public void onCreate(Bundle icicle) {
+        super.onCreate(icicle);
+        mModePreference = findPreference(PREF_KEY_MODE);
+        mModePreference.setOnPreferenceClickListener(preference -> {
+            mCapabilities = getMagnificationCapabilities(getPrefContext());
+            showDialog(DIALOG_MAGNIFICATION_CAPABILITY);
+            return true;
+        });
+    }
+
+    @Override
+    protected int getPreferenceScreenResId() {
+        return R.xml.accessibility_magnification_service_settings;
+    }
+
+    @Override
+    public Dialog onCreateDialog(int dialogId) {
+        if (dialogId == DIALOG_MAGNIFICATION_CAPABILITY) {
+            final String title = getPrefContext().getString(
+                    R.string.accessibility_magnification_mode_title);
+            AlertDialog alertDialog = AccessibilityEditDialogUtils
+                    .showMagnificationModeDialog(getPrefContext(), title,
+                            this::callOnAlertDialogCheckboxClicked);
+            initializeDialogCheckBox(alertDialog);
+            return alertDialog;
+        }
+        throw new IllegalArgumentException("Unsupported dialogId " + dialogId);
+    }
+
+    private void callOnAlertDialogCheckboxClicked(DialogInterface dialog, int which) {
+        updateCapabilities(true);
+        mModePreference.setSummary(
+                getMagnificationCapabilitiesSummary(getPrefContext()));
+    }
+
+    private void initializeDialogCheckBox(AlertDialog dialog) {
+        final View dialogFullScreenView = dialog.findViewById(R.id.magnify_full_screen);
+        mMagnifyFullScreenCheckBox = dialogFullScreenView.findViewById(R.id.checkbox);
+
+        final View dialogWidowView = dialog.findViewById(R.id.magnify_window_screen);
+        mMagnifyWindowCheckBox = dialogWidowView.findViewById(R.id.checkbox);
+
+        updateAlertDialogCheckState();
+        updateAlertDialogEnableState();
+    }
+
+    private void updateAlertDialogCheckState() {
+        updateCheckStatus(mMagnifyWindowCheckBox, MagnifyMode.WINDOW);
+        updateCheckStatus(mMagnifyFullScreenCheckBox, MagnifyMode.FULLSCREEN);
+
+    }
+
+    private void updateCheckStatus(CheckBox checkBox, int mode) {
+        checkBox.setChecked((mode & mCapabilities) != 0);
+        checkBox.setOnClickListener(v -> {
+            updateCapabilities(false);
+            updateAlertDialogEnableState();
+        });
+    }
+
+    private void updateAlertDialogEnableState() {
+        if (mCapabilities != MagnifyMode.ALL) {
+            disableEnabledMagnificationModePreference();
+        } else {
+            enableAllPreference();
+        }
+    }
+
+    private void enableAllPreference() {
+        mMagnifyFullScreenCheckBox.setEnabled(true);
+        mMagnifyWindowCheckBox.setEnabled(true);
+    }
+
+    private void disableEnabledMagnificationModePreference() {
+        if (!mMagnifyFullScreenCheckBox.isChecked()) {
+            mMagnifyWindowCheckBox.setEnabled(false);
+        } else if (!mMagnifyWindowCheckBox.isChecked()) {
+            mMagnifyFullScreenCheckBox.setEnabled(false);
+        }
+    }
+
+    private void updateCapabilities(boolean saveToDB) {
+        int capabilities = 0;
+        capabilities |=
+                mMagnifyFullScreenCheckBox.isChecked() ? MagnifyMode.FULLSCREEN : 0;
+        capabilities |= mMagnifyWindowCheckBox.isChecked() ? MagnifyMode.WINDOW : 0;
+        mCapabilities = capabilities;
+        if (saveToDB) {
+            setMagnificationCapabilities(capabilities);
+        }
+    }
+
+    private void setSecureIntValue(String key, int value) {
+        Settings.Secure.putIntForUser(getPrefContext().getContentResolver(),
+                key, value, getPrefContext().getContentResolver().getUserId());
+    }
+
+    private void setMagnificationCapabilities(int capabilities) {
+        setSecureIntValue(KEY_CAPABILITY, capabilities);
+    }
+
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({
+            MagnifyMode.NONE,
+            MagnifyMode.FULLSCREEN,
+            MagnifyMode.WINDOW,
+            MagnifyMode.ALL,
+    })
+    private @interface MagnifyMode {
+        int NONE = 0;
+        int FULLSCREEN = 1;
+        int WINDOW = 2;
+        int ALL = 3;
+    }
+
+    public static final BaseSearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
+            new BaseSearchIndexProvider(R.xml.accessibility_magnification_service_settings);
+}

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

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2019 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.os.UserHandle;
+import android.provider.Settings;
+
+import com.android.settings.core.TogglePreferenceController;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/** Controller that shows and updates the magnification window control switch. */
+public class MagnificationWindowControlPreferenceController extends TogglePreferenceController {
+
+    // TODO(b/146019459): Use magnification_window_control_enabled.
+    private static final String KEY_CONTROL = Settings.System.MASTER_MONO;
+
+    public MagnificationWindowControlPreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public boolean isChecked() {
+        return Settings.System.getIntForUser(mContext.getContentResolver(),
+                KEY_CONTROL, State.OFF, UserHandle.USER_CURRENT) == State.ON;
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        return Settings.System.putIntForUser(mContext.getContentResolver(),
+                KEY_CONTROL, isChecked ? State.ON : State.OFF, UserHandle.USER_CURRENT);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Retention(RetentionPolicy.SOURCE)
+    private @interface State {
+        int OFF = 0;
+        int ON = 1;
+    }
+}

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

@@ -54,6 +54,7 @@ import com.android.settings.widget.SwitchBar;
 public class ToggleScreenMagnificationPreferenceFragment extends
         ToggleFeaturePreferenceFragment implements SwitchBar.OnSwitchChangeListener {
 
+    private static final String SETTINGS_KEY = "screen_magnification_settings";
     private static final int DIALOG_ID_GESTURE_NAVIGATION_TUTORIAL = 1;
     private static final int DIALOG_ID_ACCESSIBILITY_BUTTON_TUTORIAL = 2;
     private static final int DIALOG_ID_EDIT_SHORTCUT = 3;
@@ -170,6 +171,13 @@ public class ToggleScreenMagnificationPreferenceFragment extends
         mVideoPreference.setPersistent(false);
         mVideoPreference.setLayoutResource(R.layout.magnification_video_preference);
 
+        final Preference settingsPreference = new Preference(getPrefContext());
+        final String SettingsText = getString(R.string.settings_button);
+        settingsPreference.setTitle(SettingsText);
+        settingsPreference.setKey(SETTINGS_KEY);
+        settingsPreference.setFragment(MagnificationSettingsFragment.class.getName());
+        settingsPreference.setPersistent(false);
+
         mConfigWarningPreference = new Preference(getPrefContext());
         mConfigWarningPreference.setSelectable(false);
         mConfigWarningPreference.setPersistent(false);
@@ -179,8 +187,10 @@ public class ToggleScreenMagnificationPreferenceFragment extends
         final PreferenceScreen preferenceScreen = getPreferenceManager().getPreferenceScreen();
         preferenceScreen.setOrderingAsAdded(false);
         mVideoPreference.setOrder(0);
+        settingsPreference.setOrder(1);
         mConfigWarningPreference.setOrder(2);
         preferenceScreen.addPreference(mVideoPreference);
+        preferenceScreen.addPreference(settingsPreference);
         preferenceScreen.addPreference(mConfigWarningPreference);
     }
 

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

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import com.android.settings.R;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+@RunWith(RobolectricTestRunner.class)
+public class MagnificationModePreferenceControllerTest {
+    private static final String PREF_KEY = "screen_magnification_mode";
+    // TODO(b/146019459): Use magnification_capability.
+    private static final String KEY_CAPABILITY = Settings.System.MASTER_MONO;
+    private static final int WINDOW_SCREEN_VALUE = 2;
+    private static final int ALL_VALUE = 3;
+
+    private Context mContext;
+    private MagnificationModePreferenceController mController;
+
+    @Before
+    public void setUp() {
+        mContext = RuntimeEnvironment.application;
+        mController = new MagnificationModePreferenceController(mContext, PREF_KEY);
+    }
+
+    @Test
+    public void getSummary_saveWindowScreen_shouldReturnWindowScreenSummary() {
+        Settings.Secure.putInt(mContext.getContentResolver(),
+                KEY_CAPABILITY, WINDOW_SCREEN_VALUE);
+
+        assertThat(mController.getSummary())
+                .isEqualTo(mContext.getString(
+                        R.string.accessibility_magnification_area_settings_window_screen_summary));
+    }
+
+    @Test
+    public void getSummary_saveAll_shouldReturnAllSummary() {
+        Settings.Secure.putInt(mContext.getContentResolver(),
+                KEY_CAPABILITY, ALL_VALUE);
+
+        assertThat(mController.getSummary())
+                .isEqualTo(mContext.getString(
+                        R.string.accessibility_magnification_area_settings_all_summary));
+    }
+}

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

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.os.UserHandle;
+import android.provider.Settings;
+
+import androidx.preference.SwitchPreference;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@RunWith(RobolectricTestRunner.class)
+public class MagnificationWindowControlPreferenceControllerTest {
+    private static final String PREF_KEY = "screen_magnification_window_control_switch";
+    // TODO(b/146019459): Use magnification_window_control_enabled.
+    private static final String KEY_CONTROL = Settings.System.MASTER_MONO;
+    private Context mContext;
+    private SwitchPreference mPreference;
+    private MagnificationWindowControlPreferenceController mController;
+
+    @Before
+    public void setUp() {
+        mContext = RuntimeEnvironment.application;
+        mPreference = new SwitchPreference(mContext);
+        mController = new MagnificationWindowControlPreferenceController(mContext, PREF_KEY);
+    }
+
+    @Test
+    public void isChecked_enabledWindowControl_shouldReturnTrue() {
+        Settings.System.putIntForUser(mContext.getContentResolver(),
+                KEY_CONTROL, State.ON, UserHandle.USER_CURRENT);
+
+        mController.updateState(mPreference);
+
+        assertThat(mController.isChecked()).isTrue();
+        assertThat(mPreference.isChecked()).isTrue();
+    }
+
+    @Test
+    public void isChecked_disabledWindowControl_shouldReturnFalse() {
+        Settings.System.putIntForUser(mContext.getContentResolver(),
+                KEY_CONTROL, State.OFF, UserHandle.USER_CURRENT);
+
+        mController.updateState(mPreference);
+
+        assertThat(mController.isChecked()).isFalse();
+        assertThat(mPreference.isChecked()).isFalse();
+    }
+
+    @Test
+    public void setChecked_setTrue_shouldEnableWindowControl() {
+        mController.setChecked(true);
+
+        assertThat(Settings.System.getIntForUser(mContext.getContentResolver(),
+                KEY_CONTROL, State.UNKNOWN, UserHandle.USER_CURRENT)).isEqualTo(State.ON);
+    }
+
+    @Test
+    public void setChecked_setFalse_shouldDisableWindowControl() {
+        mController.setChecked(false);
+
+        assertThat(Settings.System.getIntForUser(mContext.getContentResolver(),
+                KEY_CONTROL, State.UNKNOWN, UserHandle.USER_CURRENT)).isEqualTo(State.OFF);
+    }
+
+    @Retention(RetentionPolicy.SOURCE)
+    private @interface State {
+        int UNKNOWN = -1;
+        int OFF = 0;
+        int ON = 1;
+    }
+}