我正在我的安卓密码管理应用程序上创建一个AutoFillService（使用java）。
我已经关注了这个turotial
当我的服务尝试获取另一个应用程序的内容时，它似乎无法检测字段内的AutofillHint、Hint和Text。
下面是我在AutoFillService超类的onFillRequest方法中的代码：

// Get the structure from the request
List<FillContext> context = request.getFillContexts();
AssistStructure structure = context.get(context.size() - 1).getStructure();
this.appToFillName = structure.getActivityComponent().getPackageName();
System.out.println("Fill request : " + this.appToFillName);
// Traverse the structure looking for nodes to fill out.
int nodes = structure.getWindowNodeCount();
for (int i = 0; i < nodes; i++) {
    AssistStructure.ViewNode viewNode = 
    structure.getWindowNodeAt(i).getRootViewNode();
    traverseNode(viewNode);
}

然后我用traverseNode方法遍历节点：

public void traverseNode(@NonNull AssistStructure.ViewNode viewNode) {
    //my problem is that I see null objects/nothing coming out of this print function
    //even when I'm on an app where I know there are field with AutofillHints
    System.out.println(Arrays.toString(viewNode.getAutofillHints()) + "\n" + viewNode.getHint() + "\n" + viewNode.getText());
    //here I have some methods to link the autofillId when I detect a field to fill ...
    for (int i = 0; i < viewNode.getChildCount(); i++) {
        AssistStructure.ViewNode childNode = viewNode.getChildAt(i);
        traverseNode(childNode);
    }
}

谢谢你的帮助！