android
getRootInActiveWindow returns null even though android:canRetrieveWindowContent="true"
Following the Scroll button portion of the sample, the service crashes whenever the scroll button is pressed. The getRootInActiveWindow() call is returning null even though, according to the API, this should not happen when android:canRetrieveWindowContent="true", which it is in both the github repository and in my own working directory.
I found a solution, by caching the root node from received events
AccessibilityNodeInfo mLastKnownRoot; @Override public void onAccessibilityEvent(AccessibilityEvent event) { AccessibilityNodeInfo root = event.getSource(); while (root != null) { mLastKnownRoot = root; root = root.getParent(); } }
The mLastKnownRoot can be used as the argument to findScrollableNode when getRootInActiveWindow is null. Also, the permission android:accessibilityEventTypes="typeAllMask" should be added to the accessibility-service xml
