com/android/systemui/accessibility/MagnificationModeSwitch.java - platform/prebuilts/fullsdk/sources/android-31 - Git at Google

 /*
  * Copyright (C) 2020 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.systemui.accessibility;

 import static android.provider.Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_NONE;
 import static android.provider.Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW;
 import static android.view.WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS;

 import android.annotation.NonNull;
 import android.annotation.UiContext;
 import android.content.Context;
 import android.content.pm.ActivityInfo;
 import android.graphics.Insets;
 import android.graphics.PixelFormat;
 import android.graphics.Rect;
 import android.os.Bundle;
 import android.os.UserHandle;
 import android.provider.Settings;
 import android.util.MathUtils;
 import android.view.Gravity;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.WindowInsets;
 import android.view.WindowManager;
 import android.view.WindowManager.LayoutParams;
 import android.view.WindowMetrics;
 import android.view.accessibility.AccessibilityManager;
 import android.view.accessibility.AccessibilityNodeInfo;
 import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction;
 import android.widget.ImageView;

 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.graphics.SfVsyncFrameCallbackProvider;
 import com.android.systemui.R;

 import java.util.Collections;

 /**
  * Shows/hides a {@link android.widget.ImageView} on the screen and changes the values of
  * {@link Settings.Secure#ACCESSIBILITY_MAGNIFICATION_MODE} when the UI is toggled.
  * The button icon is movable by dragging and it would not overlap navigation bar window.
  * And the button UI would automatically be dismissed after displaying for a period of time.
  */
 class MagnificationModeSwitch implements MagnificationGestureDetector.OnGestureListener {

     @VisibleForTesting
     static final long FADING_ANIMATION_DURATION_MS = 300;
     @VisibleForTesting
     static final int DEFAULT_FADE_OUT_ANIMATION_DELAY_MS = 5000;
     private int mUiTimeout;
     private final Runnable mFadeInAnimationTask;
     private final Runnable mFadeOutAnimationTask;
     @VisibleForTesting
     boolean mIsFadeOutAnimating = false;

     private final Context mContext;
     private final AccessibilityManager mAccessibilityManager;
     private final WindowManager mWindowManager;
     private final ImageView mImageView;
     private final Runnable mWindowInsetChangeRunnable;
     private final SfVsyncFrameCallbackProvider mSfVsyncFrameProvider;
     private int mMagnificationMode = ACCESSIBILITY_MAGNIFICATION_MODE_NONE;
     private final LayoutParams mParams;
     @VisibleForTesting
     final Rect mDraggableWindowBounds = new Rect();
     private boolean mIsVisible = false;
     private final MagnificationGestureDetector mGestureDetector;
     private boolean mSingleTapDetected = false;
     private boolean mToLeftScreenEdge = false;

     MagnificationModeSwitch(@UiContext Context context) {
         this(context, createView(context), new SfVsyncFrameCallbackProvider());
     }

     @VisibleForTesting
     MagnificationModeSwitch(Context context, @NonNull ImageView imageView,
             SfVsyncFrameCallbackProvider sfVsyncFrameProvider) {
         mContext = context;
         mAccessibilityManager = mContext.getSystemService(AccessibilityManager.class);
         mWindowManager = mContext.getSystemService(WindowManager.class);
         mSfVsyncFrameProvider = sfVsyncFrameProvider;
         mParams = createLayoutParams(context);
         mImageView = imageView;
         mImageView.setOnTouchListener(this::onTouch);
         mImageView.setAccessibilityDelegate(new View.AccessibilityDelegate() {
             @Override
             public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfo info) {
                 super.onInitializeAccessibilityNodeInfo(host, info);
                 info.setStateDescription(formatStateDescription());
                 info.setContentDescription(mContext.getResources().getString(
                         R.string.magnification_mode_switch_description));
                 final AccessibilityAction clickAction = new AccessibilityAction(
                         AccessibilityAction.ACTION_CLICK.getId(), mContext.getResources().getString(
                         R.string.magnification_mode_switch_click_label));
                 info.addAction(clickAction);
                 info.setClickable(true);
                 info.addAction(new AccessibilityAction(R.id.accessibility_action_move_up,
                         mContext.getString(R.string.accessibility_control_move_up)));
                 info.addAction(new AccessibilityAction(R.id.accessibility_action_move_down,
                         mContext.getString(R.string.accessibility_control_move_down)));
                 info.addAction(new AccessibilityAction(R.id.accessibility_action_move_left,
                         mContext.getString(R.string.accessibility_control_move_left)));
                 info.addAction(new AccessibilityAction(R.id.accessibility_action_move_right,
                         mContext.getString(R.string.accessibility_control_move_right)));
             }

             @Override
             public boolean performAccessibilityAction(View host, int action, Bundle args) {
                 if (performA11yAction(action)) {
                     return true;
                 }
                 return super.performAccessibilityAction(host, action, args);
             }

             private boolean performA11yAction(int action) {
                 final Rect windowBounds = mWindowManager.getCurrentWindowMetrics().getBounds();
                 if (action == AccessibilityAction.ACTION_CLICK.getId()) {
                     handleSingleTap();
                 } else if (action == R.id.accessibility_action_move_up) {
                     moveButton(0, -windowBounds.height());
                 } else if (action == R.id.accessibility_action_move_down) {
                     moveButton(0, windowBounds.height());
                 } else if (action == R.id.accessibility_action_move_left) {
                     moveButton(-windowBounds.width(), 0);
                 } else if (action == R.id.accessibility_action_move_right) {
                     moveButton(windowBounds.width(), 0);
                 } else {
                     return false;
                 }
                 return true;
             }
         });
         mWindowInsetChangeRunnable = this::onWindowInsetChanged;
         mImageView.setOnApplyWindowInsetsListener((v, insets) -> {
             // Adds a pending post check to avoiding redundant calculation because this callback
             // is sent frequently when the switch icon window dragged by the users.
             if (!mImageView.getHandler().hasCallbacks(mWindowInsetChangeRunnable)) {
                 mImageView.getHandler().post(mWindowInsetChangeRunnable);
             }
             return v.onApplyWindowInsets(insets);
         });

         mFadeInAnimationTask = () -> {
             mImageView.animate()
                     .alpha(1f)
                     .setDuration(FADING_ANIMATION_DURATION_MS)
                     .start();
         };
         mFadeOutAnimationTask = () -> {
             mImageView.animate()
                     .alpha(0f)
                     .setDuration(FADING_ANIMATION_DURATION_MS)
                     .withEndAction(() -> removeButton())
                     .start();
             mIsFadeOutAnimating = true;
         };
         mGestureDetector = new MagnificationGestureDetector(context,
                 context.getMainThreadHandler(), this);
     }

     private CharSequence formatStateDescription() {
         final int stringId = mMagnificationMode == ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW
                 ? R.string.magnification_mode_switch_state_window
                 : R.string.magnification_mode_switch_state_full_screen;
         return mContext.getResources().getString(stringId);
     }

     private void applyResourcesValuesWithDensityChanged() {
         final int size = mContext.getResources().getDimensionPixelSize(
                 R.dimen.magnification_switch_button_size);
         mParams.height = size;
         mParams.width = size;
         if (mIsVisible) {
             stickToScreenEdge(mToLeftScreenEdge);
             // Reset button to make its window layer always above the mirror window.
             removeButton();
             showButton(mMagnificationMode, /* resetPosition= */false);
         }
     }

     private boolean onTouch(View v, MotionEvent event) {
         if (!mIsVisible) {
             return false;
         }
         return mGestureDetector.onTouch(event);
     }

     @Override
     public boolean onSingleTap() {
         mSingleTapDetected = true;
         handleSingleTap();
         return true;
     }

     @Override
     public boolean onDrag(float offsetX, float offsetY) {
         moveButton(offsetX, offsetY);
         return true;
     }

     @Override
     public boolean onStart(float x, float y) {
         stopFadeOutAnimation();
         return true;
     }

     @Override
     public boolean onFinish(float xOffset, float yOffset) {
         if (mIsVisible) {
             final int windowWidth = mWindowManager.getCurrentWindowMetrics().getBounds().width();
             final int halfWindowWidth = windowWidth / 2;
             mToLeftScreenEdge = (mParams.x < halfWindowWidth);
             stickToScreenEdge(mToLeftScreenEdge);
         }
         if (!mSingleTapDetected) {
             showButton(mMagnificationMode);
         }
         mSingleTapDetected = false;
         return true;
     }

     private void stickToScreenEdge(boolean toLeftScreenEdge) {
         mParams.x = toLeftScreenEdge
                 ? mDraggableWindowBounds.left : mDraggableWindowBounds.right;
         updateButtonViewLayoutIfNeeded();
     }

     private void moveButton(float offsetX, float offsetY) {
         mSfVsyncFrameProvider.postFrameCallback(l -> {
             mParams.x += offsetX;
             mParams.y += offsetY;
             updateButtonViewLayoutIfNeeded();
         });
     }

     void removeButton() {
         if (!mIsVisible) {
             return;
         }
         // Reset button status.
         mImageView.removeCallbacks(mFadeInAnimationTask);
         mImageView.removeCallbacks(mFadeOutAnimationTask);
         mImageView.animate().cancel();
         mIsFadeOutAnimating = false;
         mImageView.setAlpha(0f);
         mWindowManager.removeView(mImageView);
         mIsVisible = false;
     }

     void showButton(int mode) {
         showButton(mode, true);
     }

     /**
      * Shows magnification switch button for the specified magnification mode.
      * When the button is going to be visible by calling this method, the layout position can be
      * reset depending on the flag.
      *
      * @param mode          The magnification mode
      * @param resetPosition if the button position needs be reset
      */
     private void showButton(int mode, boolean resetPosition) {
         if (mMagnificationMode != mode) {
             mMagnificationMode = mode;
             mImageView.setImageResource(getIconResId(mode));
         }
         if (!mIsVisible) {
             if (resetPosition) {
                 mDraggableWindowBounds.set(getDraggableWindowBounds());
                 mParams.x = mDraggableWindowBounds.right;
                 mParams.y = mDraggableWindowBounds.bottom;
                 mToLeftScreenEdge = false;
             }
             mWindowManager.addView(mImageView, mParams);
             // Exclude magnification switch button from system gesture area.
             setSystemGestureExclusion();
             mIsVisible = true;
             mImageView.postOnAnimation(mFadeInAnimationTask);
             mUiTimeout = mAccessibilityManager.getRecommendedTimeoutMillis(
                     DEFAULT_FADE_OUT_ANIMATION_DELAY_MS,
                     AccessibilityManager.FLAG_CONTENT_ICONS
                             | AccessibilityManager.FLAG_CONTENT_CONTROLS);
         }
         // Refresh the time slot of the fade-out task whenever this method is called.
         stopFadeOutAnimation();
         mImageView.postOnAnimationDelayed(mFadeOutAnimationTask, mUiTimeout);
     }

     private void stopFadeOutAnimation() {
         mImageView.removeCallbacks(mFadeOutAnimationTask);
         if (mIsFadeOutAnimating) {
             mImageView.animate().cancel();
             mImageView.setAlpha(1f);
             mIsFadeOutAnimating = false;
         }
     }

     void onConfigurationChanged(int configDiff) {
         if ((configDiff & ActivityInfo.CONFIG_ORIENTATION) != 0) {
             final Rect previousDraggableBounds = new Rect(mDraggableWindowBounds);
             mDraggableWindowBounds.set(getDraggableWindowBounds());
             // Keep the Y position with the same height ratio before the window bounds and
             // draggable bounds are changed.
             final float windowHeightFraction = (float) (mParams.y - previousDraggableBounds.top)
                     / previousDraggableBounds.height();
             mParams.y = (int) (windowHeightFraction * mDraggableWindowBounds.height())
                     + mDraggableWindowBounds.top;
             stickToScreenEdge(mToLeftScreenEdge);
             return;
         }
         if ((configDiff & ActivityInfo.CONFIG_DENSITY) != 0) {
             applyResourcesValuesWithDensityChanged();
             return;
         }
         if ((configDiff & ActivityInfo.CONFIG_LOCALE) != 0) {
             updateAccessibilityWindowTitle();
             return;
         }
     }

     private void onWindowInsetChanged() {
         final Rect newBounds = getDraggableWindowBounds();
         if (mDraggableWindowBounds.equals(newBounds)) {
             return;
         }
         mDraggableWindowBounds.set(newBounds);
         stickToScreenEdge(mToLeftScreenEdge);
     }

     private void updateButtonViewLayoutIfNeeded() {
         if (mIsVisible) {
             mParams.x = MathUtils.constrain(mParams.x, mDraggableWindowBounds.left,
                     mDraggableWindowBounds.right);
             mParams.y = MathUtils.constrain(mParams.y, mDraggableWindowBounds.top,
                     mDraggableWindowBounds.bottom);
             mWindowManager.updateViewLayout(mImageView, mParams);
         }
     }

     private void updateAccessibilityWindowTitle() {
         mParams.accessibilityTitle = getAccessibilityWindowTitle(mContext);
         if (mIsVisible) {
             mWindowManager.updateViewLayout(mImageView, mParams);
         }
     }

     private void toggleMagnificationMode() {
         final int newMode =
                 mMagnificationMode ^ Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_ALL;
         mMagnificationMode = newMode;
         mImageView.setImageResource(getIconResId(newMode));
         Settings.Secure.putIntForUser(
                 mContext.getContentResolver(),
                 Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE,
                 newMode,
                 UserHandle.USER_CURRENT);
     }

     private void handleSingleTap() {
         removeButton();
         toggleMagnificationMode();
     }

     private static ImageView createView(Context context) {
         ImageView imageView = new ImageView(context);
         imageView.setClickable(true);
         imageView.setFocusable(true);
         imageView.setAlpha(0f);
         return imageView;
     }

     @VisibleForTesting
     static int getIconResId(int mode) {
         return (mode == Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_FULLSCREEN)
                 ? R.drawable.ic_open_in_new_window
                 : R.drawable.ic_open_in_new_fullscreen;
     }

     private static LayoutParams createLayoutParams(Context context) {
         final int size = context.getResources().getDimensionPixelSize(
                 R.dimen.magnification_switch_button_size);
         final LayoutParams params = new LayoutParams(
                 size,
                 size,
                 LayoutParams.TYPE_ACCESSIBILITY_MAGNIFICATION_OVERLAY,
                 LayoutParams.FLAG_NOT_FOCUSABLE,
                 PixelFormat.TRANSPARENT);
         params.gravity = Gravity.TOP | Gravity.LEFT;
         params.accessibilityTitle = getAccessibilityWindowTitle(context);
         params.layoutInDisplayCutoutMode = LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS;
         return params;
     }

     private Rect getDraggableWindowBounds() {
         final int layoutMargin = mContext.getResources().getDimensionPixelSize(
                 R.dimen.magnification_switch_button_margin);
         final WindowMetrics windowMetrics = mWindowManager.getCurrentWindowMetrics();
         final Insets windowInsets = windowMetrics.getWindowInsets().getInsetsIgnoringVisibility(
                 WindowInsets.Type.systemBars() | WindowInsets.Type.displayCutout());
         final Rect boundRect = new Rect(windowMetrics.getBounds());
         boundRect.offsetTo(0, 0);
         boundRect.inset(0, 0, mParams.width, mParams.height);
         boundRect.inset(windowInsets);
         boundRect.inset(layoutMargin, layoutMargin);
         return boundRect;
     }

     private static String getAccessibilityWindowTitle(Context context) {
         return context.getString(com.android.internal.R.string.android_system_label);
     }

     private void setSystemGestureExclusion() {
         mImageView.post(() -> {
             mImageView.setSystemGestureExclusionRects(
                     Collections.singletonList(
                             new Rect(0, 0, mImageView.getWidth(), mImageView.getHeight())));
         });
     }
 }
	/*
	* Copyright (C) 2020 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.systemui.accessibility;

	import static android.provider.Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_NONE;
	import static android.provider.Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW;
	import static android.view.WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS;

	import android.annotation.NonNull;
	import android.annotation.UiContext;
	import android.content.Context;
	import android.content.pm.ActivityInfo;
	import android.graphics.Insets;
	import android.graphics.PixelFormat;
	import android.graphics.Rect;
	import android.os.Bundle;
	import android.os.UserHandle;
	import android.provider.Settings;
	import android.util.MathUtils;
	import android.view.Gravity;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.WindowInsets;
	import android.view.WindowManager;
	import android.view.WindowManager.LayoutParams;
	import android.view.WindowMetrics;
	import android.view.accessibility.AccessibilityManager;
	import android.view.accessibility.AccessibilityNodeInfo;
	import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction;
	import android.widget.ImageView;

	import com.android.internal.annotations.VisibleForTesting;
	import com.android.internal.graphics.SfVsyncFrameCallbackProvider;
	import com.android.systemui.R;

	import java.util.Collections;

	/**
	* Shows/hides a {@link android.widget.ImageView} on the screen and changes the values of
	* {@link Settings.Secure#ACCESSIBILITY_MAGNIFICATION_MODE} when the UI is toggled.
	* The button icon is movable by dragging and it would not overlap navigation bar window.
	* And the button UI would automatically be dismissed after displaying for a period of time.
	*/
	class MagnificationModeSwitch implements MagnificationGestureDetector.OnGestureListener {

	@VisibleForTesting
	static final long FADING_ANIMATION_DURATION_MS = 300;
	@VisibleForTesting
	static final int DEFAULT_FADE_OUT_ANIMATION_DELAY_MS = 5000;
	private int mUiTimeout;
	private final Runnable mFadeInAnimationTask;
	private final Runnable mFadeOutAnimationTask;
	@VisibleForTesting
	boolean mIsFadeOutAnimating = false;

	private final Context mContext;
	private final AccessibilityManager mAccessibilityManager;
	private final WindowManager mWindowManager;
	private final ImageView mImageView;
	private final Runnable mWindowInsetChangeRunnable;
	private final SfVsyncFrameCallbackProvider mSfVsyncFrameProvider;
	private int mMagnificationMode = ACCESSIBILITY_MAGNIFICATION_MODE_NONE;
	private final LayoutParams mParams;
	@VisibleForTesting
	final Rect mDraggableWindowBounds = new Rect();
	private boolean mIsVisible = false;
	private final MagnificationGestureDetector mGestureDetector;
	private boolean mSingleTapDetected = false;
	private boolean mToLeftScreenEdge = false;

	MagnificationModeSwitch(@UiContext Context context) {
	this(context, createView(context), new SfVsyncFrameCallbackProvider());
	}

	@VisibleForTesting
	MagnificationModeSwitch(Context context, @NonNull ImageView imageView,
	SfVsyncFrameCallbackProvider sfVsyncFrameProvider) {
	mContext = context;
	mAccessibilityManager = mContext.getSystemService(AccessibilityManager.class);
	mWindowManager = mContext.getSystemService(WindowManager.class);
	mSfVsyncFrameProvider = sfVsyncFrameProvider;
	mParams = createLayoutParams(context);
	mImageView = imageView;
	mImageView.setOnTouchListener(this::onTouch);
	mImageView.setAccessibilityDelegate(new View.AccessibilityDelegate() {
	@Override
	public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfo info) {
	super.onInitializeAccessibilityNodeInfo(host, info);
	info.setStateDescription(formatStateDescription());
	info.setContentDescription(mContext.getResources().getString(
	R.string.magnification_mode_switch_description));
	final AccessibilityAction clickAction = new AccessibilityAction(
	AccessibilityAction.ACTION_CLICK.getId(), mContext.getResources().getString(
	R.string.magnification_mode_switch_click_label));
	info.addAction(clickAction);
	info.setClickable(true);
	info.addAction(new AccessibilityAction(R.id.accessibility_action_move_up,
	mContext.getString(R.string.accessibility_control_move_up)));
	info.addAction(new AccessibilityAction(R.id.accessibility_action_move_down,
	mContext.getString(R.string.accessibility_control_move_down)));
	info.addAction(new AccessibilityAction(R.id.accessibility_action_move_left,
	mContext.getString(R.string.accessibility_control_move_left)));
	info.addAction(new AccessibilityAction(R.id.accessibility_action_move_right,
	mContext.getString(R.string.accessibility_control_move_right)));
	}

	@Override
	public boolean performAccessibilityAction(View host, int action, Bundle args) {
	if (performA11yAction(action)) {
	return true;
	}
	return super.performAccessibilityAction(host, action, args);
	}

	private boolean performA11yAction(int action) {
	final Rect windowBounds = mWindowManager.getCurrentWindowMetrics().getBounds();
	if (action == AccessibilityAction.ACTION_CLICK.getId()) {
	handleSingleTap();
	} else if (action == R.id.accessibility_action_move_up) {
	moveButton(0, -windowBounds.height());
	} else if (action == R.id.accessibility_action_move_down) {
	moveButton(0, windowBounds.height());
	} else if (action == R.id.accessibility_action_move_left) {
	moveButton(-windowBounds.width(), 0);
	} else if (action == R.id.accessibility_action_move_right) {
	moveButton(windowBounds.width(), 0);
	} else {
	return false;
	}
	return true;
	}
	});
	mWindowInsetChangeRunnable = this::onWindowInsetChanged;
	mImageView.setOnApplyWindowInsetsListener((v, insets) -> {
	// Adds a pending post check to avoiding redundant calculation because this callback
	// is sent frequently when the switch icon window dragged by the users.
	if (!mImageView.getHandler().hasCallbacks(mWindowInsetChangeRunnable)) {
	mImageView.getHandler().post(mWindowInsetChangeRunnable);
	}
	return v.onApplyWindowInsets(insets);
	});

	mFadeInAnimationTask = () -> {
	mImageView.animate()
	.alpha(1f)
	.setDuration(FADING_ANIMATION_DURATION_MS)
	.start();
	};
	mFadeOutAnimationTask = () -> {
	mImageView.animate()
	.alpha(0f)
	.setDuration(FADING_ANIMATION_DURATION_MS)
	.withEndAction(() -> removeButton())
	.start();
	mIsFadeOutAnimating = true;
	};
	mGestureDetector = new MagnificationGestureDetector(context,
	context.getMainThreadHandler(), this);
	}

	private CharSequence formatStateDescription() {
	final int stringId = mMagnificationMode == ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW
	? R.string.magnification_mode_switch_state_window
	: R.string.magnification_mode_switch_state_full_screen;
	return mContext.getResources().getString(stringId);
	}

	private void applyResourcesValuesWithDensityChanged() {
	final int size = mContext.getResources().getDimensionPixelSize(
	R.dimen.magnification_switch_button_size);
	mParams.height = size;
	mParams.width = size;
	if (mIsVisible) {
	stickToScreenEdge(mToLeftScreenEdge);
	// Reset button to make its window layer always above the mirror window.
	removeButton();
	showButton(mMagnificationMode, /* resetPosition= */false);
	}
	}

	private boolean onTouch(View v, MotionEvent event) {
	if (!mIsVisible) {
	return false;
	}
	return mGestureDetector.onTouch(event);
	}

	@Override
	public boolean onSingleTap() {
	mSingleTapDetected = true;
	handleSingleTap();
	return true;
	}

	@Override
	public boolean onDrag(float offsetX, float offsetY) {
	moveButton(offsetX, offsetY);
	return true;
	}

	@Override
	public boolean onStart(float x, float y) {
	stopFadeOutAnimation();
	return true;
	}

	@Override
	public boolean onFinish(float xOffset, float yOffset) {
	if (mIsVisible) {
	final int windowWidth = mWindowManager.getCurrentWindowMetrics().getBounds().width();
	final int halfWindowWidth = windowWidth / 2;
	mToLeftScreenEdge = (mParams.x < halfWindowWidth);
	stickToScreenEdge(mToLeftScreenEdge);
	}
	if (!mSingleTapDetected) {
	showButton(mMagnificationMode);
	}
	mSingleTapDetected = false;
	return true;
	}

	private void stickToScreenEdge(boolean toLeftScreenEdge) {
	mParams.x = toLeftScreenEdge
	? mDraggableWindowBounds.left : mDraggableWindowBounds.right;
	updateButtonViewLayoutIfNeeded();
	}

	private void moveButton(float offsetX, float offsetY) {
	mSfVsyncFrameProvider.postFrameCallback(l -> {
	mParams.x += offsetX;
	mParams.y += offsetY;
	updateButtonViewLayoutIfNeeded();
	});
	}

	void removeButton() {
	if (!mIsVisible) {
	return;
	}
	// Reset button status.
	mImageView.removeCallbacks(mFadeInAnimationTask);
	mImageView.removeCallbacks(mFadeOutAnimationTask);
	mImageView.animate().cancel();
	mIsFadeOutAnimating = false;
	mImageView.setAlpha(0f);
	mWindowManager.removeView(mImageView);
	mIsVisible = false;
	}

	void showButton(int mode) {
	showButton(mode, true);
	}

	/**
	* Shows magnification switch button for the specified magnification mode.
	* When the button is going to be visible by calling this method, the layout position can be
	* reset depending on the flag.
	*
	* @param mode The magnification mode
	* @param resetPosition if the button position needs be reset
	*/
	private void showButton(int mode, boolean resetPosition) {
	if (mMagnificationMode != mode) {
	mMagnificationMode = mode;
	mImageView.setImageResource(getIconResId(mode));
	}
	if (!mIsVisible) {
	if (resetPosition) {
	mDraggableWindowBounds.set(getDraggableWindowBounds());
	mParams.x = mDraggableWindowBounds.right;
	mParams.y = mDraggableWindowBounds.bottom;
	mToLeftScreenEdge = false;
	}
	mWindowManager.addView(mImageView, mParams);
	// Exclude magnification switch button from system gesture area.
	setSystemGestureExclusion();
	mIsVisible = true;
	mImageView.postOnAnimation(mFadeInAnimationTask);
	mUiTimeout = mAccessibilityManager.getRecommendedTimeoutMillis(
	DEFAULT_FADE_OUT_ANIMATION_DELAY_MS,
	AccessibilityManager.FLAG_CONTENT_ICONS
	\| AccessibilityManager.FLAG_CONTENT_CONTROLS);
	}
	// Refresh the time slot of the fade-out task whenever this method is called.
	stopFadeOutAnimation();
	mImageView.postOnAnimationDelayed(mFadeOutAnimationTask, mUiTimeout);
	}

	private void stopFadeOutAnimation() {
	mImageView.removeCallbacks(mFadeOutAnimationTask);
	if (mIsFadeOutAnimating) {
	mImageView.animate().cancel();
	mImageView.setAlpha(1f);
	mIsFadeOutAnimating = false;
	}
	}

	void onConfigurationChanged(int configDiff) {
	if ((configDiff & ActivityInfo.CONFIG_ORIENTATION) != 0) {
	final Rect previousDraggableBounds = new Rect(mDraggableWindowBounds);
	mDraggableWindowBounds.set(getDraggableWindowBounds());
	// Keep the Y position with the same height ratio before the window bounds and
	// draggable bounds are changed.
	final float windowHeightFraction = (float) (mParams.y - previousDraggableBounds.top)
	/ previousDraggableBounds.height();
	mParams.y = (int) (windowHeightFraction * mDraggableWindowBounds.height())
	+ mDraggableWindowBounds.top;
	stickToScreenEdge(mToLeftScreenEdge);
	return;
	}
	if ((configDiff & ActivityInfo.CONFIG_DENSITY) != 0) {
	applyResourcesValuesWithDensityChanged();
	return;
	}
	if ((configDiff & ActivityInfo.CONFIG_LOCALE) != 0) {
	updateAccessibilityWindowTitle();
	return;
	}
	}

	private void onWindowInsetChanged() {
	final Rect newBounds = getDraggableWindowBounds();
	if (mDraggableWindowBounds.equals(newBounds)) {
	return;
	}
	mDraggableWindowBounds.set(newBounds);
	stickToScreenEdge(mToLeftScreenEdge);
	}

	private void updateButtonViewLayoutIfNeeded() {
	if (mIsVisible) {
	mParams.x = MathUtils.constrain(mParams.x, mDraggableWindowBounds.left,
	mDraggableWindowBounds.right);
	mParams.y = MathUtils.constrain(mParams.y, mDraggableWindowBounds.top,
	mDraggableWindowBounds.bottom);
	mWindowManager.updateViewLayout(mImageView, mParams);
	}
	}

	private void updateAccessibilityWindowTitle() {
	mParams.accessibilityTitle = getAccessibilityWindowTitle(mContext);
	if (mIsVisible) {
	mWindowManager.updateViewLayout(mImageView, mParams);
	}
	}

	private void toggleMagnificationMode() {
	final int newMode =
	mMagnificationMode ^ Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_ALL;
	mMagnificationMode = newMode;
	mImageView.setImageResource(getIconResId(newMode));
	Settings.Secure.putIntForUser(
	mContext.getContentResolver(),
	Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE,
	newMode,
	UserHandle.USER_CURRENT);
	}

	private void handleSingleTap() {
	removeButton();
	toggleMagnificationMode();
	}

	private static ImageView createView(Context context) {
	ImageView imageView = new ImageView(context);
	imageView.setClickable(true);
	imageView.setFocusable(true);
	imageView.setAlpha(0f);
	return imageView;
	}

	@VisibleForTesting
	static int getIconResId(int mode) {
	return (mode == Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_FULLSCREEN)
	? R.drawable.ic_open_in_new_window
	: R.drawable.ic_open_in_new_fullscreen;
	}

	private static LayoutParams createLayoutParams(Context context) {
	final int size = context.getResources().getDimensionPixelSize(
	R.dimen.magnification_switch_button_size);
	final LayoutParams params = new LayoutParams(
	size,
	size,
	LayoutParams.TYPE_ACCESSIBILITY_MAGNIFICATION_OVERLAY,
	LayoutParams.FLAG_NOT_FOCUSABLE,
	PixelFormat.TRANSPARENT);
	params.gravity = Gravity.TOP \| Gravity.LEFT;
	params.accessibilityTitle = getAccessibilityWindowTitle(context);
	params.layoutInDisplayCutoutMode = LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS;
	return params;
	}

	private Rect getDraggableWindowBounds() {
	final int layoutMargin = mContext.getResources().getDimensionPixelSize(
	R.dimen.magnification_switch_button_margin);
	final WindowMetrics windowMetrics = mWindowManager.getCurrentWindowMetrics();
	final Insets windowInsets = windowMetrics.getWindowInsets().getInsetsIgnoringVisibility(
	WindowInsets.Type.systemBars() \| WindowInsets.Type.displayCutout());
	final Rect boundRect = new Rect(windowMetrics.getBounds());
	boundRect.offsetTo(0, 0);
	boundRect.inset(0, 0, mParams.width, mParams.height);
	boundRect.inset(windowInsets);
	boundRect.inset(layoutMargin, layoutMargin);
	return boundRect;
	}

	private static String getAccessibilityWindowTitle(Context context) {
	return context.getString(com.android.internal.R.string.android_system_label);
	}

	private void setSystemGestureExclusion() {
	mImageView.post(() -> {
	mImageView.setSystemGestureExclusionRects(
	Collections.singletonList(
	new Rect(0, 0, mImageView.getWidth(), mImageView.getHeight())));
	});
	}
	}