Android布局语法解释

Question

here is a line in layout file

 <code><TextView 
        android:id="@+id/username"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:text="@string/username"
        android:textAppearance="?android:attr/textAppearanceMedium"</code>> 

in about context what is the exact meaning of

android:textAppearance="?android:attr/textAppearanceMedium" 

is that related to "?[package:][type:]name" , if yes then what that refers to ?

- Shrenik

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"?" 用于什么？我们也可以定义相同的东西吗？如何定义一个新的包？" - Shrenik

Answer 1

?android:attr/textAppearanceMedium 是指 android.R.attr.textAppearanceMedium。这是引用外部包资源内容的方法。

这篇文章有提到这个内容。

- xandy