使用 android espresso,如何访问第二个 activity 的视图?

Using android espresso, how to access a view of second activity?

我从登录Activity 开始,登录后,我的应用会转到下一个 Activity 并带有 RecyclerView。我需要参考 Recycler View。我正在这样做,但得到 null.

RecyclerView recyclerView = (RecyclerView) loginActivity.getActivity().findViewById(R.id.messages_list);

它是空的,因为 loginActivity 不包含 RecyclerView。所以,我的问题是,一旦我移动到第二个 activity,我如何告诉 espresso 将 loginActivity 替换为新的 activity 以便我可以执行此操作

  RecyclerView recyclerView = (RecyclerView) currentActivity.getActivity().findViewById(R.id.messages_list);

如果不行,还有什么办法?

Activity currentActivity;

public Activity getActivityInstance() {

    getInstrumentation().runOnMainSync(new Runnable() {
        public void run() {
            Collection resumedActivities = ActivityLifecycleMonitorRegistry.getInstance().getActivitiesInStage(Stage.RESUMED);
            if (resumedActivities.iterator().hasNext()) {
                currentActivity = (Activity) resumedActivities.iterator().next();
            }
        }
    });

    return currentActivity;
}

RecyclerView recyclerView = (RecyclerView) getActivityInstance().findViewById(R.id.messages_list);