为什么现在将ContextThemeWrapper限制为“支持库”组？ [英] Why is ContextThemeWrapper now restricted to the Support Library group?

问题描述

我开始使用 ContextThemeWrapper 将样式动态地应用于 ImageButton ；基于我的另一个问题的答案，以及其他相似 问题。

I started using a ContextThemeWrapper to apply a style dynamically to an ImageButton; based an answer to another question of mine, and answers to other similar questions.

ContextThemeWrapper wrapper = new ContextThemeWrapper(getContext(), mStyleRes);
mImageButton = new AppCompatImageButton(wrapper, null, 0);

但是最近在 ContextThemeWrapper 构造函数说明：

But recently a lint error started appearing on the ContextThemeWrapper constructor stating:

ContextThemeWrapper 只能从同一库中调用
组（groupId = com.android.support）

ContextThemeWrapper can only be called from within the same library group (groupId=com.android.support)

我注意到该类标记为 @RestrictTo（LIBRARY_GROUP）批注，这会导致出现棉绒错误。但是我找不到关于为什么的任何信息，它仅限于 com.android.support 库组。

I noticed that the class marked with the @RestrictTo(LIBRARY_GROUP) annotation, which is causing the lint error to appear. But I cannot find any information as to why it is restricted to the com.android.support library group.

据我所知，这是将样式，主题或主题叠加层以编程方式应用于 View 的唯一方法；除了将默认样式属性设置为构造函数中的第三个参数之外。所以我想知道为什么它的使用会受到限制。在支持库之外使用类是否有问题？可能会有我不知道的副作用吗？

As far as I can tell, this is the only way to apply a style, theme or theme overlay to a View programmatically; other than setting a default style attribute as the third argument in the constructor. So I am wondering why its use would be restricted at all; is there some issue with using the class outside of the support libraries? Could there be side-effects that I am not aware of?

唯一的我遇到的类似问题是关于一个（现已修复）错误的问题；导致此棉绒错误显示在 AppCompatActivity 子类的 onCreate 方法上。我认为这种情况不是错误，而是有意的限制。我想知道背后的原因。

The only similar question that I have come across is one about a (now fixed) bug; that caused this lint error to be displayed on the onCreate method of a subclass of AppCompatActivity. I do not think this occurrence is a bug, rather a deliberate restriction; which I would like to know the reasoning behind.

我应该注意；实际上，使用 ContextThemeWrapper 这种限制（到目前为止）实际上对代码没有任何影响。

I should note; this restriction (as of now) actually seems to have no effect on the code using a ContextThemeWrapper. It compiles and runs fine, and works as I would expect it to.

推荐答案

android.view.ContextThemeWrapper ！= android.support.v7.view.ContextThemeWrapper 。

注释了一个支持库 @RestrictTo（LIBRARY_GROUP） 以及 @hide -并不是要成为公共API。

The support library one is annotated @RestrictTo(LIBRARY_GROUP), and also @hide - it's not meant to be a public API.

第一个是公开的。

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