您参考安卓资源，这是在Android系统已经定义， @android：ID /..，而在你的项目中创建已定义的接入资源/，可以使用 @id /..

you refer to Android resources , which are already defined in Android system, with @android:id/.. while to access resources that you have defined/created in your project, you use @id/..

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按照在聊天你澄清，你说你有一个这样的问题：

As per your clarifications in the chat, you said you have a problem like this :

如果我们使用机器人：ID =@ ID / layout_item_id这是行不通的。相反 @ + ID / 工作有啥区别就在这里？这是我原来的问题。

If we use android:id="@id/layout_item_id" it doesn't work. Instead @+id/ works so what's the difference here? And that was my original question.

嗯，这取决于上下文，当你使用的XML属性机器人：ID ，那么你指定一个新的ID，并指示解析器（或称之为生成器）创建于 R.java 新条目，因此，你必须包括 + 标志。

Well, it depends on the context, when you're using the XML attribute of android:id, then you're specifying a new id, and are instructing the parser (or call it the builder) to create a new entry in R.java, thus you have to include a + sign.

而在其他情况下，如安卓layout_below =@ ID / myTextView，你指的是已经创建了一个ID，所以解析器链接这在已创建的ID R.java 。

While in the other case, like android:layout_below="@id/myTextView" , you're referring to an id that has already been created, so parser links this to the already created id in R.java.

更多信息再次

正如你在聊天说，请注意，安卓layout_below =@ ID / myTextView将无法识别ID为元素 myTextView 如果你使用它的元素之后写的。

As you said in your chat, note that android:layout_below="@id/myTextView" won't recognize an element with id myTextViewif it is written after the element you're using it in.