什么是ButtonBarLayout，我们应该如何使用它? [英] What is the ButtonBarLayout and how should we use it?

问题描述

开发时，我意外地发现了一个名为android.support.v7.widget.ButtonBarLayout的新窗口小部件.我试图在Internet上进行搜索，但是即使在官方开发文档站点上也没有找到任何内容.

同时，当我在 Android Studio 中的任何地方搜索ButtonBarLayout时，我发现了两个ButtonBarLayout，一个是android.support.v7.widget.ButtonBarLayout，另一个是com.android.internal.widget.ButtonBarLayout.我试图阅读两者的源代码，发现除了软件包名称之外，它们是相同的.因此，我认为android.support.v7.widget.ButtonBarLayout来自com.android.internal.widget.ButtonBarLayout，可能是内部ButtonBarLayout 经过测试并发布的.同时，ButtonBarLayout是从LinearLayout继承的.

但是有一些问题:

• 从ButtonBarLayout的字面意义上我们可以得到什么?我们应该如何使用它?
• 我注意到了private boolean mAllowStacking的变量.当它改变时，该布局的方向将改变.但是我真的不明白它的用途.

那么有人知道ButtonBarLayout吗?

PS:我使用的是 2.0.0 Preview 4 的 Android Studio 和 2.0.0-alpha3 的 Gradle Plugin 23.1.1 的strong>和 Android支持库，以及 23.1 和 Build-工具( 23.0.2 ).

解决方案

此处的源代码

When I developed, I found a new widget called android.support.v7.widget.ButtonBarLayout unexpectedly. I tried to search it on the internet, but nothing was found, even on the official development documents site.

In the meantime, I found two ButtonBarLayout when I search ButtonBarLayout everywhere in Android Studio, one is android.support.v7.widget.ButtonBarLayout and the other is com.android.internal.widget.ButtonBarLayout. I tried to read source codes of both, I found that they are the same except package name. So I thought maybe android.support.v7.widget.ButtonBarLayout came from com.android.internal.widget.ButtonBarLayout after the internal ButtonBarLayout was through tests and released. At the same time, ButtonBarLayout is inherited from LinearLayout.

But there are some question:

• What can we get from ButtonBarLayout literally and how should we use it?
• I noticed the variable of private boolean mAllowStacking. When it changes, orientation of this layout would be changed. But I didn't really understand what it is used for.

So does somebody know ButtonBarLayout well?

P.S.: I used Android Studio of 2.0.0 Preview 4 and Gradle Plugin of 2.0.0-alpha3 and Android Support Library of 23.1.1 and Platform-tools of 23.1 and Build-tools of 23.0.2.

解决方案

The source code describes ButtonBarLayout as follows:

/**
 * An extension of LinearLayout that automatically switches to vertical
 * orientation when it can't fit its child views horizontally.
 */

So, in essence, it is nothing but a smart LinearLayout which manages auto-switching orientations based on available space on screen.

The same ButtonBarLayout.java file describes mAllowStacking in comments as follows:

/** Whether the current configuration allows stacking. */

Source Code Here

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