关于布局别名的Android文档不正确？ [英] Incorrect Android documentation about layout aliases?

问题描述

我想知道如何重用或别名布局与最少的样板代码。

I'd like to figure out how to reuse or "alias" layouts with the least boilerplate code.

似乎关于布局别名的Android文档是不正确的，当然会出现不一致。本部分文档显示以下布局文件为例：

It seems that the Android documentation about layout aliases is incorrect, and certainly appears inconsistent. This section of documentation shows the following layout file as an example:

<resources>
    <item name="main" type="layout">@layout/main_twopanes</item>
</resources>

如果我尝试编译，我得到一个属性缺少Android命名空间前缀错误。即使将命名空间添加到资源元素后，我得到错误：错误：不允许使用字符串类型（'type'，值为'layout'） 。

If I try to compile this, I get an Attribute is missing the Android namespace prefix error. Even after adding the namespace to the resources element, I get error: Error: String types not allowed (at 'type' with value 'layout').

在Android文档中的其他地方，它们显示了一种不同的，看似颠倒和不正确的别名布局方式：

Elsewhere in the Android documentation, they show a different and seemingly inverted and incorrect way to alias layouts:

要创建现有布局的别名，请使用包含在< merge> 中的元素
。例如：

To create an alias to an existing layout, use the element, wrapped in a <merge>. For example:

<?xml version="1.0" encoding="utf-8"?>
<merge>
    <include layout="@layout/main_ltr"/>
</merge>

运行此结果会导致LogCat中的以下错误 E / AndroidRuntime（1558）：android.view.InflateException：< merge />只能使用一个有效的ViewGroup根和attachToRoot = true 。所以这个错误似乎加强了这个事实：这个< include> < merge> pair必须是一个错误，因为它需要一个不必要的父母查看。

Running this results in the following error in LogCat E/AndroidRuntime(1558): android.view.InflateException: <merge /> can be used only with a valid ViewGroup root and attachToRoot=true. So this error seems to reinforce the fact that this <include> <merge> pair must be a mistake, because it requires an unnecessary parent View.

最后还有一个 < merge> 文档，与前一个方向相矛盾，没有提到顶级< merge>< include />< / merge> 的倒置形式。

Lastly there's the <merge> documentation, which seems to contradict the former direction, making no mention of the inverted form of a top-level <merge><include/></merge>.

为避免包含这样一个冗余视图组，您可以使用
该元素作为可重用布局的根视图。对于
示例：

To avoid including such a redundant view group, you can instead use the element as the root view for the re-usable layout. For example:

<merge xmlns:android="http://schemas.android.com/apk/res/android">

    <Button
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content"
        android:text="@string/add"/>

    <Button
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content"
        android:text="@string/delete"/>

</merge>

推荐答案

工作，您只需将< resources> 文件放在正确的文件夹中。它应该在值文件夹中，而不是布局文件夹，您可以通过重用布局< include> 。

The first technique works, you just have to put your <resources> file in the correct folder. It should be in the values folders not the layout folders as you might when reusing layouts via <include>.

例如，假设您有一个名为 editor.xml ，它们位于布局文件夹中。假设您想在 small 和正常屏幕尺寸上使用专门的布局。如果您不在乎重复自己，您只需将此布局复制并粘贴到布局小和布局正常文件夹，并在每个文件夹中命名为$ code> editor.xml 。所以你会有三个名为 editor.xml 的文件。

For instance, suppose you have a layout named editor.xml that lives in the layout folder. Suppose you want to use a specialized layout on small and normal screen sizes. If you didn't care about repeating yourself, you would just copy and paste this layout into the layout-small and layout-normal folders and name it editor.xml in each folder. So you'd have three files named editor.xml.

如果你不想重复，您将将专门的布局放在主要的布局文件夹中，并将其命名为 compact_editor.xml 。然后，您将在 values-small 和值中创建一个名为 layout.xml 的文件-normal 文件夹。每个文件将显示为：

If you don't want to repeat yourself, you would place the specialized layout in the main layout folder and name it, say, compact_editor.xml. Then you'd create a file named layout.xml in the values-small and values-normal folders. Each file would read:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <item name="editor" type="layout">@layout/compact_editor</item>
</resources>

我已提交文档问题其他两个问题。

I've filed a documentation issue about the other two problems.

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