android - 导航组件中使用的标签属性是什么？

Question

根据docs :

The Label field contains the name of the destination’s XML layout file.

很公平，但我似乎无法找到它的用途。为什么布局文件需要命名？

<fragment
    android:id="@+id/blank"
    android:name="com.example.app.BlankFragment"
    android:label="Blank"
    tools:layout="@layout/fragment_blank"/>

label 属性是否严格用于导航框架的内部工作，而不是我应该担心的事情？

Answer 1

根据 Update UI components with NavigationUI documentation :

NavigationUI contains methods that automatically update content in your top app bar as users navigate through your app. For example, NavigationUI uses the destination labels from your navigation graph to keep the title of the top app bar up-to-date.

When using NavigationUI with the top app bar methods discussed below, the label you attach to destinations can be automatically populated from the arguments provided to the destination by using the format of {argName} in your label.

就像附加到每个目的地的任何其他信息一样，它也可以用在 custom OnDestinationChangedListener 中。如果您有其他 UI 需要使用当前目的地的标签进行更新。