Question

我刚刚阅读了android中的数据绑定功能。我试图从嵌套布局绑定视图。我的活动是android的默认模板DrawerMenuActivity，并且content_my_activity布局嵌套在activity_my_activity布局中。

我有3个自动生成的绑定类。 MyActivityBinding，AppBarMyActivityBinding和ContentMyActivityBinding。

我尝试初始化所有3个类，如下所示：

MyActivity.java

MyActivityBinding activityBinding;
AppBarMyActivityBinding appBarBinding;
ContentMyActivityBinding contentBinding;

protected void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);

    activityBinding = DataBindingUtils.setContentView(this, 
                               R.layout.activity_my_activity);
    appBarBinding = DataBindingUtils.setContentView(this, 
                               R.layout.app_bar_my_activity);
    contentBinding = DataBindingUtils.setContentView(this, 
                               R.layout.content_my_activity);

    setName();
}

private void setName(){
    contentBinding.setFirstName("Omkar");
}

但它会抛出RuntimeException，如下所示：

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example, PID: 18305
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example/com.example.userInterface.activity.MyActivity}: android.view.InflateException: Binary XML file line #35: Binary XML file line #27: Error inflating class fragment
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2426)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2490)
    at android.app.ActivityThread.access$900(ActivityThread.java:154)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:148)
    at android.app.ActivityThread.main(ActivityThread.java:5443)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
 Caused by: android.view.InflateException: Binary XML file line #35: Binary XML file line #27: Error inflating class fragment
    at android.view.LayoutInflater.inflate(LayoutInflater.java:539)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
    at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:280)
    at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
    at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:276)
    at com.example.userInterface.activity.MyActivity.onCreate(MyActivity.java:88)
    at android.app.Activity.performCreate(Activity.java:6259)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1130)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2490) 
    at android.app.ActivityThread.access$900(ActivityThread.java:154) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:148) 
    at android.app.ActivityThread.main(ActivityThread.java:5443) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
 Caused by: android.view.InflateException: Binary XML file line #27: Error inflating class fragment
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:782)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:835)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:838)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
    at android.view.LayoutInflater.parseInclude(LayoutInflater.java:971)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:831)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:374) 
    at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:280) 
    at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140) 
    at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:276) 
    at com.example.userInterface.activity.MyActivity.onCreate(MyActivity.java:88) 
    at android.app.Activity.performCreate(Activity.java:6259) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1130) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2490) 
    at android.app.ActivityThread.access$900(ActivityThread.java:154) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:148) 
    at android.app.ActivityThread.main(ActivityThread.java:5443) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
 Caused by: java.lang.IllegalArgumentException: Binary XML file line #27: Duplicate id 0x7f0e0081, tag null, or parent id 0xffffffff with another fragment for com.google.android.gms.maps.SupportMapFragment
    at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2416)
    at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
    at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:374)
    at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:33)
    at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:75)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:754)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704) 
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:835) 
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798) 
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:838) 
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798) 
    at android.view.LayoutInflater.parseInclude(LayoutInflater.java:971) 
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:831) 
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:515) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:374) 
    at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:280) 
    at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140) 
    at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:276) 
    at com.example.userInterface.activity.MyActivity.onCreate(MyActivity.java:88) 
    at android.app.Activity.performCreate(Activity.java:6259) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1130) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2490) 
    at android.app.ActivityThread.access$900(ActivityThread.java:154) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:148) 
    at android.app.ActivityThread.main(ActivityThread.java:5443) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

如何在MyActivity.java类中绑定来自content_my_activity的视图，感谢任何帮助。

感谢。

Answer 1

DataBindingUtils.setContentView()确实如何命名：它将当前视图设置为给定参数。我不认为你想要AppBar作为整个观点，或者你呢？

尽管如此，我认为您include中的布局layout_activity_main.xml。 George Mount撰写了关于此功能的whole blog帖子。代码示例来自这篇文章。

第一个示例是您的layout_activity_main.xml（或者您已将其命名），其中包含AppBar，Content等。

hello_world.xml
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

        <TextView
                android:id="@+id/hello"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>
        <include
                android:id="@+id/world1"
                layout="@layout/included_layout"/>
        <include
                android:id="@+id/world2"
                layout="@layout/included_layout"/>
    </LinearLayout>
</layout>


included_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/world"/>
</layout>

既然已使用的布局清晰明了，您就需要跳转到ActivityMain，初始化DataBinding并访问您的字段：

//This works if you have used a variable in your <data> tag and you have built your project afterwards, if you don't have an activity
HelloWorldBinding binding = HelloWorldBinding.inflate(getLayoutInflater());

 //if you have an activity, you can use setContentView from the DataBindingUtils. Don't forget to delete the generic setContentView
HelloWorldBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_my_activity);


//Once you have accomplished the above, you can access your data-bound fields like this:
binding.hello.setText(“Hello”);
binding.world1.world.setText(“First World”);
binding.world2.world.setText(“Second World”);

请务必将Ids设置为<include>代码，以便在Activity时正确访问它们。

Answer 2

一个人可以用XML传递对象……需要xmlns:bind名称空间（类似于xmlns:app）。

<?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>

示例的

来源：Layouts and binding expressions。

如何在嵌套布局中设置Android DataBinding

2 个答案: