NavigationView 获取/查找标题布局 [英] NavigationView get/find header layout

问题描述

在我的 NavigationView 中，我有一个标题布局，id 为viewId"，带有活动按钮.要设置这些按钮，我在活动的 onPostCreate 中执行以下操作:

In my NavigationView I have a header layout with id 'viewId' with active buttons. To setup those buttons, I do the following in activity's onPostCreate:

final View panel = findViewById(R.id.viewId);
panel.setOnClickListener(new View.OnClickListener() {
... setup goes here ...
});

使用新版本的 android 支持库 (23.1.0)，无法找到视图，返回 null.对于以前的版本，它运行良好.这是错误还是我使用此功能有误?如果是这样，如何访问标题布局并向其添加行为?

With new version android support library, (23.1.0), the view can't be found, it returns null. With previous versions it worked well. Is it a bug or am I using this feature wrong? If so, how to access header layout and add behavior to it?

推荐答案

23.1.0 版将 NavigationView 切换为使用 RecyclerView(而不是之前的 ListView) 并将标题添加为这些元素之一.这意味着它不能立即调用 findViewById() - 在它附加到 NavigationView 之前需要一个布局传递.

Version 23.1.0 switches NavigationView to using a RecyclerView (rather than the previous ListView) and the header is added as one of those elements. This means it is not instantly available to call findViewById() - a layout pass is needed before it is attached to the NavigationView.

对于版本 23.1.1 的支持库，您现在可以获得使用 getHeaderView() 引用标题视图:

For version 23.1.1 of the Support Library, you can now get a reference to the header view using getHeaderView():

View headerLayout = navigationView.getHeaderView(0); // 0-index header

这有利于处理通过 XML 和代码添加的标头.

This has the advantage of working on headers added via XML and via code.

如果您仍在使用 23.1.0，根据 相关错误，您可以在代码中扩展标题并在其上使用 findViewById() :

If you are still using 23.1.0, as per the related bug, you can inflate the header in code and use findViewById() on that:

View headerLayout = 
    navigationView.inflateHeaderView(R.layout.navigation_header);
panel = headerLayout.findViewById(R.id.viewId);
// panel won't be null

直到您移动到 ​​23.1.1.

Until you move to 23.1.1.

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