Android工具栏溢出菜单视图ID [英] Android Toolbar overflow menu view id

问题描述

我要做的是显示一个PopupWindow，它指向工具栏上的溢出图标(三个点).因此，我需要使用图标的ID获取对View对象的引用.但是，身份证是什么?

What I am trying to do is showing a PopupWindow pointing to the overflow icon (the three dots) on the Toolbar. So I need to get a reference to the View object with the id of the icon. But what is the id?

PopupWindow用于告诉用户有新条目添加到溢出菜单中.并建议用户检查一下.

The PopupWindow is used to tell the users that there are new entries added to the overflow menu. And suggest users to check it out.

推荐答案

溢出菜单项没有资源ID.我通过遍历工具栏找到了溢出视图.调试器显示的ID为 -1 ，而Hierarchy Viewer没有显示资源ID.

The overflow menu item doesn't have a resource id. I found the overflow view by traversing the toolbar. The debugger showed an id of -1 and the Hierarchy Viewer showed no resource-id.

这是我如何找到没有资源ID的溢出视图的方法:

Here is how I found the overflow view without a resource id:

/**
 * Get the OverflowMenuButton.
 *
 * @param activity
 *     the Activity
 * @return the OverflowMenuButton or {@code null} if it doesn't exist.
 */
public static ImageView getOverflowMenuButton(Activity activity) {
  return findOverflowMenuButton(activity, findActionBar(activity));
}

static ImageView findOverflowMenuButton(Activity activity, ViewGroup viewGroup) {
  if (viewGroup == null) {
    return null;
  }
  ImageView overflow = null;
  for (int i = 0, count = viewGroup.getChildCount(); i < count; i++) {
    View v = viewGroup.getChildAt(i);
    if (v instanceof ImageView && (v.getClass().getSimpleName().equals("OverflowMenuButton") ||
        v instanceof ActionMenuView.ActionMenuChildView)) {
      overflow = (ImageView) v;
    } else if (v instanceof ViewGroup) {
      overflow = findOverflowMenuButton(activity, (ViewGroup) v);
    }
    if (overflow != null) {
      break;
    }
  }
  return overflow;
}

static ViewGroup findActionBar(Activity activity) {
  try {
    int id = activity.getResources().getIdentifier("action_bar", "id", "android");
    ViewGroup actionBar = null;
    if (id != 0) {
      actionBar = (ViewGroup) activity.findViewById(id);
    }
    if (actionBar == null) {
      return findToolbar((ViewGroup) activity.findViewById(android.R.id.content).getRootView());
    }
  } catch (Exception e) {
    e.printStackTrace();
  }
  return null;
}

static ViewGroup findToolbar(ViewGroup viewGroup) {
  ViewGroup toolbar = null;
  for (int i = 0, len = viewGroup.getChildCount(); i < len; i++) {
    View view = viewGroup.getChildAt(i);
    if (view.getClass() == android.support.v7.widget.Toolbar.class ||
        view.getClass().getName().equals("android.widget.Toolbar")) {
      toolbar = (ViewGroup) view;
    } else if (view instanceof ViewGroup) {
      toolbar = findToolbar((ViewGroup) view);
    }
    if (toolbar != null) {
      break;
    }
  }
  return toolbar;
}

调用 getOverflowMenuButton(activity)将在 onCreate 中返回 null ，因为尚未设置溢出菜单.为了在onCreate中获得溢出菜单，我执行了以下操作:

Calling getOverflowMenuButton(activity) will return null in onCreate because the overflow menu isn't laid out yet. To get the overflow menu in onCreate I did the following:

findViewById(android.R.id.content).post(new Runnable() {
  @Override public void run() {
    ImageView overflow = getOverflowMenuButton(MainActivity.this);
  }
});

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