accessibilityNodeInfo AlertDialog的子节点始终为空。如何获取按钮？

@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
    AccessibilityNodeInfo rootNode = getRootInActiveWindow();
    if (rootNode != null) {
        findButtonInAlertDialog(rootNode);
        rootNode.recycle();
    }
}

private void findButtonInAlertDialog(AccessibilityNodeInfo nodeInfo) {
    if (nodeInfo == null) {
        return;
    }

    int childCount = nodeInfo.getChildCount();
    for (int i = 0; i < childCount; i++) {
        AccessibilityNodeInfo childNode = nodeInfo.getChild(i);
        if (childNode != null) {
            // 判断节点类型是否是按钮
            if (childNode.getClassName().equals(Button.class.getName())) {
                // 获取按钮文本
                String buttonText = childNode.getText().toString();
                // 这里可以根据按钮文本做进一步的处理
                // ...
                Log.d(TAG, "Button text: " + buttonText);
            }

            findButtonInAlertDialog(childNode); // 递归查找子节点
            childNode.recycle();
        }
    }
}