Adding an opt-in mechanism for gesture detection in AccessibilityService.

1. An accessibility service has to explicitly opt in to be notified
   for gestures by the system. There is only one accessibility service
   that handles gestures and in case it does not handle a gesture
   the system performs default handling. This default handling ensures
   that we have gesture navigation even if no accessibility service
   would like to participate/customize the interaction model.

bug:5932640

Change-Id: Id8194293bd94097b455e9388b68134a45dc3b8fa

9 files changed, 124 insertions, 115 deletions

diff --git a/core/java/android/accessibilityservice/AccessibilityService.java b/core/java/android/accessibilityservice/AccessibilityService.java
index 4e340c0..c858e3c 100644
--- a/core/java/android/accessibilityservice/AccessibilityService.java
+++ b/core/java/android/accessibilityservice/AccessibilityService.java
@@ -19,22 +19,17 @@ package android.accessibilityservice;
 import android.app.Service;
 import android.content.Context;
 import android.content.Intent;
-import android.content.res.Configuration;
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.Message;
 import android.os.RemoteException;
-import android.util.LocaleUtil;
 import android.util.Log;
-import android.view.View;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityInteractionClient;
 import android.view.accessibility.AccessibilityNodeInfo;
 
 import com.android.internal.os.HandlerCaller;
 
-import java.util.Locale;
-
 /**
  * An accessibility service runs in the background and receives callbacks by the system
  * when {@link AccessibilityEvent}s are fired. Such events denote some state transition
@@ -299,6 +294,16 @@ public abstract class AccessibilityService extends Service {
     public static final int GESTURE_SWIPE_DOWN_AND_RIGHT = 18;
 
     /**
+     * The user has performed a two finger tap gesture on the touch screen.
+     */
+    public static final int GESTURE_TWO_FINGER_TAP = 19;
+
+    /**
+     * The user has performed a two finger long press gesture on the touch screen.
+     */
+    public static final int GESTURE_TWO_FINGER_LONG_PRESS = 20;
+
+    /**
      * The {@link Intent} that must be declared as handled by the service.
      */
     public static final String SERVICE_INTERFACE =
@@ -342,8 +347,6 @@ public abstract class AccessibilityService extends Service {
      */
     public static final int GLOBAL_ACTION_NOTIFICATIONS = 4;
 
-    private static final int UNDEFINED = -1;
-
     private static final String LOG_TAG = "AccessibilityService";
 
     interface Callbacks {
@@ -351,15 +354,13 @@ public abstract class AccessibilityService extends Service {
         public void onInterrupt();
         public void onServiceConnected();
         public void onSetConnectionId(int connectionId);
-        public void onGesture(int gestureId);
+        public boolean onGesture(int gestureId);
     }
 
     private int mConnectionId;
 
     private AccessibilityServiceInfo mInfo;
 
-    private int mLayoutDirection;
-
     /**
      * Callback for {@link android.view.accessibility.AccessibilityEvent}s.
      *
@@ -386,95 +387,43 @@ public abstract class AccessibilityService extends Service {
 
     /**
      * Called by the system when the user performs a specific gesture on the
-     * touch screen.
+     * touch screen. If the gesture is not handled in this callback the system
+     * may provide default handing. Therefore, one should return true from this
+     * function if overriding of default behavior is desired.
+     *
+     * <strong>Note:</strong> To receive gestures an accessibility service
+     *         must declare that it can handle such by specifying the
+     *         <code>&lt;{@link android.R.styleable#AccessibilityService_canHandleGestures
+     *         canHandleGestures}&gt;</code> attribute.
      *
      * @param gestureId The unique id of the performed gesture.
      *
+     * @return Whether the gesture was handled.
+     *
      * @see #GESTURE_SWIPE_UP
-     * @see #GESTURE_SWIPE_DOWN
-     * @see #GESTURE_SWIPE_LEFT
-     * @see #GESTURE_SWIPE_RIGHT
+     * @see #GESTURE_SWIPE_UP_AND_LEFT
      * @see #GESTURE_SWIPE_UP_AND_DOWN
+     * @see #GESTURE_SWIPE_UP_AND_RIGHT
+     * @see #GESTURE_SWIPE_DOWN
+     * @see #GESTURE_SWIPE_DOWN_AND_LEFT
      * @see #GESTURE_SWIPE_DOWN_AND_UP
+     * @see #GESTURE_SWIPE_DOWN_AND_RIGHT
+     * @see #GESTURE_SWIPE_LEFT
+     * @see #GESTURE_SWIPE_LEFT_AND_UP
      * @see #GESTURE_SWIPE_LEFT_AND_RIGHT
+     * @see #GESTURE_SWIPE_LEFT_AND_DOWN
+     * @see #GESTURE_SWIPE_RIGHT
+     * @see #GESTURE_SWIPE_RIGHT_AND_UP
      * @see #GESTURE_SWIPE_RIGHT_AND_LEFT
+     * @see #GESTURE_SWIPE_RIGHT_AND_DOWN
      * @see #GESTURE_CLOCKWISE_CIRCLE
      * @see #GESTURE_COUNTER_CLOCKWISE_CIRCLE
+     * @see #GESTURE_TWO_FINGER_TAP
+     * @see #GESTURE_TWO_FINGER_LONG_PRESS
      */
-    protected void onGesture(int gestureId) {
+    protected boolean onGesture(int gestureId) {
         // TODO: Describe the default gesture processing in the javaDoc once it is finalized.
-
-        // Global actions.
-        switch (gestureId) {
-            case GESTURE_SWIPE_DOWN_AND_LEFT: {
-                performGlobalAction(GLOBAL_ACTION_BACK);
-            } return;
-            case GESTURE_SWIPE_DOWN_AND_RIGHT: {
-                performGlobalAction(GLOBAL_ACTION_HOME);
-            } return;
-            case GESTURE_SWIPE_UP_AND_LEFT: {
-                performGlobalAction(GLOBAL_ACTION_RECENTS);
-            } return;
-            case GESTURE_SWIPE_UP_AND_RIGHT: {
-                performGlobalAction(GLOBAL_ACTION_NOTIFICATIONS);
-            } return;
-        }
-
-        // Cache the id to avoid locking
-        final int connectionId = mConnectionId;
-        if (connectionId == UNDEFINED) {
-            throw new IllegalStateException("AccessibilityService not connected."
-                    + " Did you receive a call of onServiceConnected()?");
-        }
-        AccessibilityNodeInfo root = getRootInActiveWindow();
-        if (root == null) {
-            return;
-        }
-
-        AccessibilityNodeInfo current = root.findFocus(AccessibilityNodeInfo.FOCUS_ACCESSIBILITY);
-        if (current == null) {
-            current = root;
-        }
-
-        // Local actions.
-        AccessibilityNodeInfo next = null;
-        switch (gestureId) {
-            case GESTURE_SWIPE_UP: {
-                next = current.focusSearch(View.ACCESSIBILITY_FOCUS_OUT);
-            } break;
-            case GESTURE_SWIPE_DOWN: {
-                next = current.focusSearch(View.ACCESSIBILITY_FOCUS_IN);
-            } break;
-            case GESTURE_SWIPE_LEFT: {
-                if (mLayoutDirection == View.LAYOUT_DIRECTION_LTR) {
-                    next = current.focusSearch(View.ACCESSIBILITY_FOCUS_BACKWARD);
-                } else { // LAYOUT_DIRECTION_RTL
-                    next = current.focusSearch(View.ACCESSIBILITY_FOCUS_FORWARD);
-                }
-            } break;
-            case GESTURE_SWIPE_RIGHT: {
-                if (mLayoutDirection == View.LAYOUT_DIRECTION_LTR) {
-                    next = current.focusSearch(View.ACCESSIBILITY_FOCUS_FORWARD);
-                } else { // LAYOUT_DIRECTION_RTL
-                    next = current.focusSearch(View.ACCESSIBILITY_FOCUS_BACKWARD);
-                }
-            } break;
-            case GESTURE_SWIPE_UP_AND_DOWN: {
-                next = current.focusSearch(View.ACCESSIBILITY_FOCUS_UP);
-            } break;
-            case GESTURE_SWIPE_DOWN_AND_UP: {
-                next = current.focusSearch(View.ACCESSIBILITY_FOCUS_DOWN);
-            } break;
-            case GESTURE_SWIPE_LEFT_AND_RIGHT: {
-                next = current.focusSearch(View.ACCESSIBILITY_FOCUS_LEFT);
-            } break;
-            case GESTURE_SWIPE_RIGHT_AND_LEFT: {
-                next = current.focusSearch(View.ACCESSIBILITY_FOCUS_RIGHT);
-            } break;
-        }
-        if (next != null && !next.equals(current)) {
-            next.performAction(AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS);
-        }
+        return false;
     }
 
     /**
@@ -484,10 +433,7 @@ public abstract class AccessibilityService extends Service {
      * @return The root node if this service can retrieve window content.
      */
     public AccessibilityNodeInfo getRootInActiveWindow() {
-        return AccessibilityInteractionClient.getInstance()
-            .findAccessibilityNodeInfoByAccessibilityId(mConnectionId,
-                AccessibilityNodeInfo.ACTIVE_WINDOW_ID, AccessibilityNodeInfo.ROOT_NODE_ID,
-                AccessibilityNodeInfo.FLAG_PREFETCH_DESCENDANTS);
+        return AccessibilityInteractionClient.getInstance().getRootInActiveWindow(mConnectionId);
     }
 
     /**
@@ -509,7 +455,7 @@ public abstract class AccessibilityService extends Service {
             AccessibilityInteractionClient.getInstance().getConnection(mConnectionId);
         if (connection != null) {
             try {
-                return connection.perfromGlobalAction(action);
+                return connection.performGlobalAction(action);
             } catch (RemoteException re) {
                 Log.w(LOG_TAG, "Error while calling performGlobalAction", re);
             }
@@ -572,18 +518,6 @@ public abstract class AccessibilityService extends Service {
         }
     }
 
-    @Override
-    public void onCreate() {
-        Locale locale = getResources().getConfiguration().locale;
-        mLayoutDirection = LocaleUtil.getLayoutDirectionFromLocale(locale);
-    }
-
-    @Override
-    public void onConfigurationChanged(Configuration configuration) {
-        super.onConfigurationChanged(configuration);
-        mLayoutDirection = LocaleUtil.getLayoutDirectionFromLocale(configuration.locale);
-    }
-
     /**
      * Implement to return the implementation of the internal accessibility
      * service interface.
@@ -612,8 +546,8 @@ public abstract class AccessibilityService extends Service {
             }
 
             @Override
-            public void onGesture(int gestureId) {
-                AccessibilityService.this.onGesture(gestureId);
+            public boolean onGesture(int gestureId) {
+                return AccessibilityService.this.onGesture(gestureId);
             }
         });
     }
@@ -658,8 +592,10 @@ public abstract class AccessibilityService extends Service {
             mCaller.sendMessage(message);
         }
 
-        public void onGesture(int gestureId) {
-            Message message = mCaller.obtainMessageI(DO_ON_GESTURE, gestureId);
+        public void onGesture(int gestureId, IAccessibilityServiceClientCallback callback,
+                int interactionId) {
+            Message message = mCaller.obtainMessageIIO(DO_ON_GESTURE, gestureId, interactionId,
+                    callback);
             mCaller.sendMessage(message);
         }
 
@@ -692,7 +628,15 @@ public abstract class AccessibilityService extends Service {
                     return;
                 case DO_ON_GESTURE :
                     final int gestureId = message.arg1;
-                    mCallback.onGesture(gestureId);
+                    final int interactionId = message.arg2;
+                    IAccessibilityServiceClientCallback callback =
+                        (IAccessibilityServiceClientCallback) message.obj;
+                    final boolean handled = mCallback.onGesture(gestureId);
+                    try {
+                        callback.setGestureResult(gestureId, handled, interactionId);
+                    } catch (RemoteException re) {
+                        Log.e(LOG_TAG, "Error calling back with the gesture resut.", re);
+                    }
                     return;
                 default :
                     Log.w(LOG_TAG, "Unknown message type " + message.what);
diff --git a/core/java/android/accessibilityservice/AccessibilityServiceInfo.java b/core/java/android/accessibilityservice/AccessibilityServiceInfo.java
index e77ed9a..7e6786b 100644
--- a/core/java/android/accessibilityservice/AccessibilityServiceInfo.java
+++ b/core/java/android/accessibilityservice/AccessibilityServiceInfo.java
@@ -224,6 +224,11 @@ public class AccessibilityServiceInfo implements Parcelable {
     private boolean mCanRetrieveWindowContent;
 
     /**
+     * Flag whether this accessibility service can handle gestures.
+     */
+    private boolean mCanHandleGestures;
+
+    /**
      * Resource id of the description of the accessibility service.
      */
     private int mDescriptionResId;
@@ -303,6 +308,8 @@ public class AccessibilityServiceInfo implements Parcelable {
             mCanRetrieveWindowContent = asAttributes.getBoolean(
                     com.android.internal.R.styleable.AccessibilityService_canRetrieveWindowContent,
                     false);
+            mCanHandleGestures = asAttributes.getBoolean(
+                    com.android.internal.R.styleable.AccessibilityService_canHandleGestures, false);
             TypedValue peekedValue = asAttributes.peekValue(
                     com.android.internal.R.styleable.AccessibilityService_description);
             if (peekedValue != null) {
@@ -378,13 +385,25 @@ public class AccessibilityServiceInfo implements Parcelable {
      *    <strong>Statically set from
      *    {@link AccessibilityService#SERVICE_META_DATA meta-data}.</strong>
      * </p>
-     * @return True window content can be retrieved.
+     * @return True if window content can be retrieved.
      */
     public boolean getCanRetrieveWindowContent() {
         return mCanRetrieveWindowContent;
     }
 
     /**
+     * Whether this service can handle gestures.
+     * <p>
+     *    <strong>Statically set from
+     *    {@link AccessibilityService#SERVICE_META_DATA meta-data}.</strong>
+     * </p>
+     * @return True if the service can handle gestures.
+     */
+    public boolean getCanHandleGestures() {
+        return mCanHandleGestures;
+    }
+
+    /**
      * Gets the non-localized description of the accessibility service.
      * <p>
      *    <strong>Statically set from
diff --git a/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl b/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
index 588728c..0257aa4 100644
--- a/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
+++ b/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
@@ -16,6 +16,7 @@
 
 package android.accessibilityservice;
 
+import android.accessibilityservice.IAccessibilityServiceClientCallback;
 import android.accessibilityservice.IAccessibilityServiceConnection;
 import android.view.accessibility.AccessibilityEvent;
 
@@ -32,5 +33,5 @@ import android.view.accessibility.AccessibilityEvent;
 
     void onInterrupt();
 
-    void onGesture(int gestureId);
+    void onGesture(int gesture, in IAccessibilityServiceClientCallback callback, int interactionId);
 }
diff --git a/core/java/android/accessibilityservice/IAccessibilityServiceClientCallback.aidl b/core/java/android/accessibilityservice/IAccessibilityServiceClientCallback.aidl
new file mode 100644
index 0000000..9061398
--- /dev/null
+++ b/core/java/android/accessibilityservice/IAccessibilityServiceClientCallback.aidl
@@ -0,0 +1,30 @@
+/*
+** Copyright 2012, 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 android.accessibilityservice;
+
+import android.accessibilityservice.IAccessibilityServiceConnection;
+import android.view.accessibility.AccessibilityEvent;
+
+/**
+ * Callback for IAccessibilityServiceClient.
+ *
+ * @hide
+ */
+ oneway interface IAccessibilityServiceClientCallback {
+
+    void setGestureResult(int gestureId, boolean handled, int interactionId);
+}
diff --git a/core/java/android/accessibilityservice/IAccessibilityServiceConnection.aidl b/core/java/android/accessibilityservice/IAccessibilityServiceConnection.aidl
index 1bd5387..6e85665 100644
--- a/core/java/android/accessibilityservice/IAccessibilityServiceConnection.aidl
+++ b/core/java/android/accessibilityservice/IAccessibilityServiceConnection.aidl
@@ -167,5 +167,5 @@ interface IAccessibilityServiceConnection {
      * @param action The action to perform.
      * @return Whether the action was performed.
      */
-    boolean perfromGlobalAction(int action);
+    boolean performGlobalAction(int action);
 }
diff --git a/core/java/android/accessibilityservice/UiTestAutomationBridge.java b/core/java/android/accessibilityservice/UiTestAutomationBridge.java
index c840bd6..1697df0 100644
--- a/core/java/android/accessibilityservice/UiTestAutomationBridge.java
+++ b/core/java/android/accessibilityservice/UiTestAutomationBridge.java
@@ -177,8 +177,8 @@ public class UiTestAutomationBridge {
             }
 
             @Override
-            public void onGesture(int gestureId) {
-                /* do nothing */
+            public boolean onGesture(int gestureId) {
+                return false;
             }
         });
 
diff --git a/core/java/android/view/accessibility/AccessibilityInteractionClient.java b/core/java/android/view/accessibility/AccessibilityInteractionClient.java
index 35f0d9d..f73faf3 100644
--- a/core/java/android/view/accessibility/AccessibilityInteractionClient.java
+++ b/core/java/android/view/accessibility/AccessibilityInteractionClient.java
@@ -84,7 +84,7 @@ public final class AccessibilityInteractionClient
 
     private final Object mInstanceLock = new Object();
 
-    private int mInteractionId = -1;
+    private volatile int mInteractionId = -1;
 
     private AccessibilityNodeInfo mFindAccessibilityNodeInfoResult;
 
@@ -150,6 +150,18 @@ public final class AccessibilityInteractionClient
     }
 
     /**
+     * Gets the root {@link AccessibilityNodeInfo} in the currently active window.
+     *
+     * @param connectionId The id of a connection for interacting with the system.
+     * @return The root {@link AccessibilityNodeInfo} if found, null otherwise.
+     */
+    public AccessibilityNodeInfo getRootInActiveWindow(int connectionId) {
+        return findAccessibilityNodeInfoByAccessibilityId(connectionId,
+                AccessibilityNodeInfo.ACTIVE_WINDOW_ID, AccessibilityNodeInfo.ROOT_NODE_ID,
+                AccessibilityNodeInfo.FLAG_PREFETCH_DESCENDANTS);
+    }
+
+    /**
      * Finds an {@link AccessibilityNodeInfo} by accessibility id.
      *
      * @param connectionId The id of a connection for interacting with the system.
diff --git a/core/res/res/values/attrs.xml b/core/res/res/values/attrs.xml
index 6f489d4..aa47993 100755
--- a/core/res/res/values/attrs.xml
+++ b/core/res/res/values/attrs.xml
@@ -2470,6 +2470,8 @@
         <!-- Flag whether the accessibility service wants to be able to retrieve the
              active window content. This setting cannot be changed at runtime. -->
         <attr name="canRetrieveWindowContent" format="boolean" />
+        <!-- Flag whether the accessibility service can handle gesrures and wants such. -->
+        <attr name="canHandleGestures" format="boolean" />
         <!-- Short description of the accessibility serivce purpose or behavior.-->
         <attr name="description" />
     </declare-styleable>
diff --git a/core/res/res/values/public.xml b/core/res/res/values/public.xml
index 03ba08c..3f8036b 100644
--- a/core/res/res/values/public.xml
+++ b/core/res/res/values/public.xml
@@ -3599,5 +3599,6 @@
   <public type="attr" name="parentActivityName" />
 
   <public type="attr" name="importantForAccessibility"/>
+  <public type="attr" name="canHandleGestures"/>
 
 </resources>