chrome/android/java/src/org/chromium/chrome/browser/util/AccessibilityUtil.java - chromium/src - Git at Google

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 package org.chromium.chrome.browser.util;

 import android.accessibilityservice.AccessibilityServiceInfo;
 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Build;
 import android.support.v7.app.AlertDialog;
 import android.view.Gravity;
 import android.view.View;
 import android.view.accessibility.AccessibilityManager;

 import org.chromium.base.ActivityState;
 import org.chromium.base.ApplicationStatus;
 import org.chromium.base.ApplicationStatus.ActivityStateListener;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.PackageUtils;
 import org.chromium.base.TraceEvent;
 import org.chromium.chrome.R;
 import org.chromium.ui.widget.Toast;

 import java.util.List;

 /**
  * Exposes information about the current accessibility state
  */
 public class AccessibilityUtil {
     // Whether we've already shown an alert that they have an old version of TalkBack running.
     private static boolean sOldTalkBackVersionAlertShown;

     // The link to download or update TalkBack from the Play Store.
     private static final String TALKBACK_MARKET_LINK =
             "market://search?q=pname:com.google.android.marvin.talkback";

     // The package name for TalkBack, an Android accessibility service.
     private static final String TALKBACK_PACKAGE_NAME =
             "com.google.android.marvin.talkback";

     // The minimum TalkBack version that we support. This is the version that shipped with
     // KitKat, from fall 2013. Versions older than that should be updated.
     private static final int MIN_TALKBACK_VERSION = 105;

     private static Boolean sIsAccessibilityEnabled;
     private static ActivityStateListener sActivityStateListener;

     private AccessibilityUtil() { }

     /**
      * Checks to see that this device has accessibility and touch exploration enabled.
      * @return        Whether or not accessibility and touch exploration are enabled.
      */
     public static boolean isAccessibilityEnabled() {
         TraceEvent.begin("AccessibilityManager::isAccessibilityEnabled");
         if (sIsAccessibilityEnabled != null) return sIsAccessibilityEnabled;

         AccessibilityManager manager =
                 (AccessibilityManager) ContextUtils.getApplicationContext().getSystemService(
                         Context.ACCESSIBILITY_SERVICE);
         boolean accessibilityEnabled =
                 manager != null && manager.isEnabled() && manager.isTouchExplorationEnabled();

         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && manager != null
                 && manager.isEnabled() && !accessibilityEnabled) {
             List<AccessibilityServiceInfo> services = manager.getEnabledAccessibilityServiceList(
                     AccessibilityServiceInfo.FEEDBACK_ALL_MASK);
             for (AccessibilityServiceInfo service : services) {
                 if (canPerformGestures(service)) {
                     accessibilityEnabled = true;
                     break;
                 }
             }
         }

         sIsAccessibilityEnabled = accessibilityEnabled;

         sActivityStateListener = new ApplicationStatus.ActivityStateListener() {
             @Override
             public void onActivityStateChange(Activity activity, int newState) {
                 // If an activity is being resumed, it's possible the user changed accessibility
                 // settings while not in a Chrome activity. Reset the accessibility enabled state
                 // so that the next time #isAccessibilityEnabled is called the accessibility state
                 // is recalculated. Also, if all activities are destroyed, remove the activity
                 // state listener to avoid leaks.
                 if (newState == ActivityState.RESUMED
                         || ApplicationStatus.isEveryActivityDestroyed()) {
                     resetAccessibilityEnabled();
                 }
             }
         };
         ApplicationStatus.registerStateListenerForAllActivities(sActivityStateListener);

         TraceEvent.end("AccessibilityManager::isAccessibilityEnabled");
         return sIsAccessibilityEnabled;
     }

     /**
      * Reset the static used to determine whether accessibility is enabled.
      * TODO(twellington): Make this private and have classes that care about accessibility state
      *                    observe this class rather than observing the AccessibilityManager
      *                    directly.
      */
     public static void resetAccessibilityEnabled() {
         ApplicationStatus.unregisterActivityStateListener(sActivityStateListener);
         sActivityStateListener = null;
         sIsAccessibilityEnabled = null;
     }

     /**
      * Checks whether the given {@link AccesibilityServiceInfo} can perform gestures.
      * @param service The service to check.
      * @return Whether the {@code service} can perform gestures. On N+, this relies on the
      *         capabilities the service can perform. On L & M, this looks specifically for
      *         Switch Access.
      */
     private static boolean canPerformGestures(AccessibilityServiceInfo service) {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
             return (service.getCapabilities()
                            & AccessibilityServiceInfo.CAPABILITY_CAN_PERFORM_GESTURES)
                     != 0;
         } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
             return service.getResolveInfo() != null
                     && service.getResolveInfo().toString().contains("switchaccess");
         }
         return false;
     }

     /**
      * Checks to see if an old version of TalkBack is running that Chrome doesn't support,
      * and if so, shows an alert dialog prompting the user to update the app.
      * @param context A {@link Context} instance.
      * @return        True if the dialog was shown.
      */
     public static boolean showWarningIfOldTalkbackRunning(Context context) {
         AccessibilityManager manager = (AccessibilityManager)
                 context.getSystemService(Context.ACCESSIBILITY_SERVICE);
         if (manager == null) return false;

         boolean isTalkbackRunning = false;
         try {
             List<AccessibilityServiceInfo> services =
                     manager.getEnabledAccessibilityServiceList(
                             AccessibilityServiceInfo.FEEDBACK_SPOKEN);
             for (AccessibilityServiceInfo service : services) {
                 if (service.getId().contains(TALKBACK_PACKAGE_NAME)) isTalkbackRunning = true;
             }
         } catch (NullPointerException e) {
             // getEnabledAccessibilityServiceList() can throw an NPE due to a bad
             // AccessibilityService.
         }
         if (!isTalkbackRunning) return false;

         if (PackageUtils.getPackageVersion(context, TALKBACK_PACKAGE_NAME) < MIN_TALKBACK_VERSION
                 && !sOldTalkBackVersionAlertShown) {
             showOldTalkbackVersionAlertOnce(context);
             return true;
         }

         return false;
     }

     private static void showOldTalkbackVersionAlertOnce(final Context context) {
         if (sOldTalkBackVersionAlertShown) return;
         sOldTalkBackVersionAlertShown = true;

         AlertDialog.Builder builder =
                 new AlertDialog.Builder(context, R.style.Theme_Chromium_AlertDialog)
                         .setTitle(R.string.old_talkback_title)
                         .setPositiveButton(R.string.update_from_market,
                                 new DialogInterface.OnClickListener() {
                                     @Override
                                     public void onClick(DialogInterface dialog, int id) {
                                         Uri marketUri = Uri.parse(TALKBACK_MARKET_LINK);
                                         Intent marketIntent =
                                                 new Intent(Intent.ACTION_VIEW, marketUri);
                                         context.startActivity(marketIntent);
                                     }
                                 })
                         .setNegativeButton(R.string.cancel_talkback_alert,
                                 new DialogInterface.OnClickListener() {
                                     @Override
                                     public void onClick(DialogInterface dialog, int id) {
                                         // Do nothing, this alert is only shown once either way.
                                     }
                                 });
         AlertDialog dialog = builder.create();
         dialog.show();
     }

     /**
      * Shows the content description toast for items on the toolbar.
      * @param context The context to use for the toast.
      * @param view The view to anchor the toast.
      * @param description The string shown in the toast.
      * @return Whether a toast has been shown successfully.
      */
     @SuppressLint("RtlHardcoded")
     public static boolean showAccessibilityToast(
             Context context, View view, CharSequence description) {
         if (description == null) return false;

         final int screenWidth = context.getResources().getDisplayMetrics().widthPixels;
         final int screenHeight = context.getResources().getDisplayMetrics().heightPixels;
         final int[] screenPos = new int[2];
         view.getLocationOnScreen(screenPos);
         final int width = view.getWidth();
         final int height = view.getHeight();

         final int horizontalGravity =
                 (screenPos[0] < screenWidth / 2) ? Gravity.LEFT : Gravity.RIGHT;
         final int xOffset = (screenPos[0] < screenWidth / 2)
                 ? screenPos[0] + width / 2
                 : screenWidth - screenPos[0] - width / 2;
         final int yOffset = (screenPos[1] < screenHeight / 2) ? screenPos[1] + height / 2
                                                               : screenPos[1] - height * 3 / 2;

         Toast toast = Toast.makeText(context, description, Toast.LENGTH_SHORT);
         toast.setGravity(Gravity.TOP | horizontalGravity, xOffset, yOffset);
         toast.show();
         return true;
     }
 }
	// Copyright 2014 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	package org.chromium.chrome.browser.util;

	import android.accessibilityservice.AccessibilityServiceInfo;
	import android.annotation.SuppressLint;
	import android.app.Activity;
	import android.content.Context;
	import android.content.DialogInterface;
	import android.content.Intent;
	import android.net.Uri;
	import android.os.Build;
	import android.support.v7.app.AlertDialog;
	import android.view.Gravity;
	import android.view.View;
	import android.view.accessibility.AccessibilityManager;

	import org.chromium.base.ActivityState;
	import org.chromium.base.ApplicationStatus;
	import org.chromium.base.ApplicationStatus.ActivityStateListener;
	import org.chromium.base.ContextUtils;
	import org.chromium.base.PackageUtils;
	import org.chromium.base.TraceEvent;
	import org.chromium.chrome.R;
	import org.chromium.ui.widget.Toast;

	import java.util.List;

	/**
	* Exposes information about the current accessibility state
	*/
	public class AccessibilityUtil {
	// Whether we've already shown an alert that they have an old version of TalkBack running.
	private static boolean sOldTalkBackVersionAlertShown;

	// The link to download or update TalkBack from the Play Store.
	private static final String TALKBACK_MARKET_LINK =
	"market://search?q=pname:com.google.android.marvin.talkback";

	// The package name for TalkBack, an Android accessibility service.
	private static final String TALKBACK_PACKAGE_NAME =
	"com.google.android.marvin.talkback";

	// The minimum TalkBack version that we support. This is the version that shipped with
	// KitKat, from fall 2013. Versions older than that should be updated.
	private static final int MIN_TALKBACK_VERSION = 105;

	private static Boolean sIsAccessibilityEnabled;
	private static ActivityStateListener sActivityStateListener;

	private AccessibilityUtil() { }

	/**
	* Checks to see that this device has accessibility and touch exploration enabled.
	* @return Whether or not accessibility and touch exploration are enabled.
	*/
	public static boolean isAccessibilityEnabled() {
	TraceEvent.begin("AccessibilityManager::isAccessibilityEnabled");
	if (sIsAccessibilityEnabled != null) return sIsAccessibilityEnabled;

	AccessibilityManager manager =
	(AccessibilityManager) ContextUtils.getApplicationContext().getSystemService(
	Context.ACCESSIBILITY_SERVICE);
	boolean accessibilityEnabled =
	manager != null && manager.isEnabled() && manager.isTouchExplorationEnabled();

	if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && manager != null
	&& manager.isEnabled() && !accessibilityEnabled) {
	List<AccessibilityServiceInfo> services = manager.getEnabledAccessibilityServiceList(
	AccessibilityServiceInfo.FEEDBACK_ALL_MASK);
	for (AccessibilityServiceInfo service : services) {
	if (canPerformGestures(service)) {
	accessibilityEnabled = true;
	break;
	}
	}
	}

	sIsAccessibilityEnabled = accessibilityEnabled;

	sActivityStateListener = new ApplicationStatus.ActivityStateListener() {
	@Override
	public void onActivityStateChange(Activity activity, int newState) {
	// If an activity is being resumed, it's possible the user changed accessibility
	// settings while not in a Chrome activity. Reset the accessibility enabled state
	// so that the next time #isAccessibilityEnabled is called the accessibility state
	// is recalculated. Also, if all activities are destroyed, remove the activity
	// state listener to avoid leaks.
	if (newState == ActivityState.RESUMED
	\|\| ApplicationStatus.isEveryActivityDestroyed()) {
	resetAccessibilityEnabled();
	}
	}
	};
	ApplicationStatus.registerStateListenerForAllActivities(sActivityStateListener);

	TraceEvent.end("AccessibilityManager::isAccessibilityEnabled");
	return sIsAccessibilityEnabled;
	}

	/**
	* Reset the static used to determine whether accessibility is enabled.
	* TODO(twellington): Make this private and have classes that care about accessibility state
	* observe this class rather than observing the AccessibilityManager
	* directly.
	*/
	public static void resetAccessibilityEnabled() {
	ApplicationStatus.unregisterActivityStateListener(sActivityStateListener);
	sActivityStateListener = null;
	sIsAccessibilityEnabled = null;
	}

	/**
	* Checks whether the given {@link AccesibilityServiceInfo} can perform gestures.
	* @param service The service to check.
	* @return Whether the {@code service} can perform gestures. On N+, this relies on the
	* capabilities the service can perform. On L & M, this looks specifically for
	* Switch Access.
	*/
	private static boolean canPerformGestures(AccessibilityServiceInfo service) {
	if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
	return (service.getCapabilities()
	& AccessibilityServiceInfo.CAPABILITY_CAN_PERFORM_GESTURES)
	!= 0;
	} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
	return service.getResolveInfo() != null
	&& service.getResolveInfo().toString().contains("switchaccess");
	}
	return false;
	}

	/**
	* Checks to see if an old version of TalkBack is running that Chrome doesn't support,
	* and if so, shows an alert dialog prompting the user to update the app.
	* @param context A {@link Context} instance.
	* @return True if the dialog was shown.
	*/
	public static boolean showWarningIfOldTalkbackRunning(Context context) {
	AccessibilityManager manager = (AccessibilityManager)
	context.getSystemService(Context.ACCESSIBILITY_SERVICE);
	if (manager == null) return false;

	boolean isTalkbackRunning = false;
	try {
	List<AccessibilityServiceInfo> services =
	manager.getEnabledAccessibilityServiceList(
	AccessibilityServiceInfo.FEEDBACK_SPOKEN);
	for (AccessibilityServiceInfo service : services) {
	if (service.getId().contains(TALKBACK_PACKAGE_NAME)) isTalkbackRunning = true;
	}
	} catch (NullPointerException e) {
	// getEnabledAccessibilityServiceList() can throw an NPE due to a bad
	// AccessibilityService.
	}
	if (!isTalkbackRunning) return false;

	if (PackageUtils.getPackageVersion(context, TALKBACK_PACKAGE_NAME) < MIN_TALKBACK_VERSION
	&& !sOldTalkBackVersionAlertShown) {
	showOldTalkbackVersionAlertOnce(context);
	return true;
	}

	return false;
	}

	private static void showOldTalkbackVersionAlertOnce(final Context context) {
	if (sOldTalkBackVersionAlertShown) return;
	sOldTalkBackVersionAlertShown = true;

	AlertDialog.Builder builder =
	new AlertDialog.Builder(context, R.style.Theme_Chromium_AlertDialog)
	.setTitle(R.string.old_talkback_title)
	.setPositiveButton(R.string.update_from_market,
	new DialogInterface.OnClickListener() {
	@Override
	public void onClick(DialogInterface dialog, int id) {
	Uri marketUri = Uri.parse(TALKBACK_MARKET_LINK);
	Intent marketIntent =
	new Intent(Intent.ACTION_VIEW, marketUri);
	context.startActivity(marketIntent);
	}
	})
	.setNegativeButton(R.string.cancel_talkback_alert,
	new DialogInterface.OnClickListener() {
	@Override
	public void onClick(DialogInterface dialog, int id) {
	// Do nothing, this alert is only shown once either way.
	}
	});
	AlertDialog dialog = builder.create();
	dialog.show();
	}

	/**
	* Shows the content description toast for items on the toolbar.
	* @param context The context to use for the toast.
	* @param view The view to anchor the toast.
	* @param description The string shown in the toast.
	* @return Whether a toast has been shown successfully.
	*/
	@SuppressLint("RtlHardcoded")
	public static boolean showAccessibilityToast(
	Context context, View view, CharSequence description) {
	if (description == null) return false;

	final int screenWidth = context.getResources().getDisplayMetrics().widthPixels;
	final int screenHeight = context.getResources().getDisplayMetrics().heightPixels;
	final int[] screenPos = new int[2];
	view.getLocationOnScreen(screenPos);
	final int width = view.getWidth();
	final int height = view.getHeight();

	final int horizontalGravity =
	(screenPos[0] < screenWidth / 2) ? Gravity.LEFT : Gravity.RIGHT;
	final int xOffset = (screenPos[0] < screenWidth / 2)
	? screenPos[0] + width / 2
	: screenWidth - screenPos[0] - width / 2;
	final int yOffset = (screenPos[1] < screenHeight / 2) ? screenPos[1] + height / 2
	: screenPos[1] - height * 3 / 2;

	Toast toast = Toast.makeText(context, description, Toast.LENGTH_SHORT);
	toast.setGravity(Gravity.TOP \| horizontalGravity, xOffset, yOffset);
	toast.show();
	return true;
	}
	}