如何将 <merge> 与视图绑定一起使用？

Question

我无法获得带有合并根标记的布局来处理视图绑定。是否可以？

include_layout.xml：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <include
        android:id="@+id/include_test"
        layout="@layout/merge_layout"/>
</FrameLayout>

合并布局.xml：

<?xml version="1.0" encoding="utf-8"?>
<merge
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/include_test">

    <TextView
        android:id="@+id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="A Title"/>
</merge>

override fun onCreate(savedInstanceState: Bundle?) {
  super.onCreate(savedInstanceState)
  val binding = IncludeLayoutBinding.inflate(layoutInflater)
  setContentView(binding.root)
  binding.includeTest.title.text = "New Title"
}

运行时异常： java.lang.NullPointerException: Missing required view with ID: includeTest

Answer 1

根据这篇文章，这是可能的

例如 ：

my_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
  <include
    layout="@layout/my_include_layout"/>
</LinearLayout>

my_include_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<merge
  xmlns:android="http://schemas.android.com/apk/res/android">
  <Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Button" />
</merge>

MyFragment.kt

class MyFragment: Fragment() {
 private val binding: MyFragmentBinding get() = _binding!!
 private var _binding: MyFragmentBinding? = null
 private val myIncludeLayoutBinding: MyIncludeLayoutBinding get() = _myIncludeLayoutBinding!!
 private var _myIncludeLayoutBinding: MyIncludeLayoutBinding? = null

 override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
    _binding = MyFragmentBinding.inflate(inflater, container, false)
    _myIncludeLayoutBinding = MyIncludeLayoutBinding.bind(binding.root)
    return binding.root
 }

 override fun onActivityCreated(savedInstanceState: Bundle?) {
    super.onActivityCreated(savedInstanceState)
    myIncludeLayoutBinding.button.setOnClickListener{
        
    }
 }

 override fun onDestroyView() {
    super.onDestroyView()
    _binding = null
    _myIncludeLayoutBinding = null
 }
}

Answer 2

不支持。

请参阅此处的官方文档：

https://developer.android.com/topic/libraries/data-binding/expressions

编辑：哎呀，这些文档讨论的是数据绑定，而不是视图绑定。