问可访问性服务看不到覆盖

EN

@Override
public void onAccessibilityEvent(AccessibilityEvent event)
{
    final String appPackageName = event.getPackageName().toString();

    if (appPackageName.equals("testappone")){
        AccessibilityNodeInfo source = getRootInActiveWindow();

        processEvent(source);
    }
}

private void processEvent(AccessibilityNodeInfo source){
   StringBuilder sb = new StringBuilder();
   processSubEvent(source, 0, sb);
   String string = sb.toString();

   Log.e(TAG, "String " + string);
}

private void processSubEvent(final AccessibilityNodeInfo source, final int n, final StringBuilder sb){

   sb.append(tools.getText(source));
   sb.append("\n");

   int childCount = source.getChildCount();
   for (int i = 0; i < childCount; i++)
   {
       AccessibilityNodeInfo child = source.getChild(i);

       if (child != null)
       {
           processSubEvent(child, n + 1, sb);
       }

     child.recycle();
   }
}