使用相同的数据绑定上下文分解复杂的XML布局

Question

Context

XML layouts in Android can get complicated. Hence, it is a good practice to break them down into conceptually independent modules. Consider the following example:

Main layout:

<layout>
   <data>
       <variable name="someVar" type="some.custom.Type"/>
   </data>

   <SomeLayout 
       ...
       android:someAttribute="@{someVar.someProperty}" />

   <include layout="@layout/some_other_layout />
</layout>

and some_other_layout.xml :

<SomeOtherLayout 
       ...
       android:someOtherAttribute="@{someVar.someOtherProperty}" />

Problem

Is it possible to use the same data-binding context (whatever is inside <data> ) in two separated layouts (like in the given example)?

Doing this naively results in java.lang.IllegalStateException .

Answer 1

From the Data Binding Library documentation :

Variables may be passed into an included layout's binding from the containing layout by using the application namespace and the variable name in an attribute:

 <?xml version="1.0" encoding="utf-8"?> <layout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:bind="http://schemas.android.com/apk/res-auto"> <data> <variable name="user" type="com.example.User"/> </data> <LinearLayout android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <include layout="@layout/name" bind:user="@{user}"/> <include layout="@layout/contact" bind:user="@{user}"/> </LinearLayout> </layout>