Adding API for getting the root node info in the active window.

1. This APIs is useful for accessibility services since very often
   they want to get access to the root node in the current window
   to determine where accessibility focus is and subsequently find
   a next view to take accessibility focus.

Change-Id: Ide5231f832d9ce2e9b14dc411dfd675f753a4edb

1 files changed, 15 insertions, 4 deletions

diff --git a/core/java/android/accessibilityservice/AccessibilityService.java b/core/java/android/accessibilityservice/AccessibilityService.java
index eed8aa6..4e340c0 100644
--- a/core/java/android/accessibilityservice/AccessibilityService.java
+++ b/core/java/android/accessibilityservice/AccessibilityService.java
@@ -426,13 +426,11 @@ public abstract class AccessibilityService extends Service {
             throw new IllegalStateException("AccessibilityService not connected."
                     + " Did you receive a call of onServiceConnected()?");
         }
-        AccessibilityNodeInfo root = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByAccessibilityId(connectionId,
-                        AccessibilityNodeInfo.ACTIVE_WINDOW_ID, AccessibilityNodeInfo.ROOT_NODE_ID,
-                        AccessibilityNodeInfo.FLAG_PREFETCH_DESCENDANTS);
+        AccessibilityNodeInfo root = getRootInActiveWindow();
         if (root == null) {
             return;
         }
+
         AccessibilityNodeInfo current = root.findFocus(AccessibilityNodeInfo.FOCUS_ACCESSIBILITY);
         if (current == null) {
             current = root;
@@ -480,6 +478,19 @@ public abstract class AccessibilityService extends Service {
     }
 
     /**
+     * Gets the root node in the currently active window if this service
+     * can retrieve window content.
+     *
+     * @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);
+    }
+
+    /**
      * Performs a global action. Such an action can be performed
      * at any moment regardless of the current application or user
      * location in that application. For example going back, going