如何在Java中将视图绑定与包含的视图一起使用？

Question

View Binding随v3.6一起发布。

https://developer.android.com/topic/libraries/view-binding

我将对包含的布局使用视图绑定。

因此，我参考以下有用的答案。

How to use View Binding with Included Views?

但是效果不好。

当然，我试图这样用Java编写。

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        binding = ActivityMainBinding.inflate(getLayoutInflater());

        setContentView(binding.getRoot());

        mainBinding.myHeader.foo.setText("this is a test");
    }
}

主布局包括另一个布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <include
        android:id="@+id/my_header"
        layout="@layout/item_header"
        android:layout_width="match_parent"
        android:layout_height="100dp" />

</LinearLayout>

但是，发生以下错误。

2020-04-21 10:18:25.135 30977-30977/com.test.binding E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.test.binding, PID: 30977
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.binding/com.test.binding.MainActivity}: java.lang.NullPointerException: Missing required view with ID: foo
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.lang.NullPointerException: Missing required view with ID: foo
        at com.test.binding.databinding.ItemHeaderBinding.bind(ItemHeaderBinding.java:102)
        at com.test.binding.databinding.ActivityMainBinding.bind(ActivityMainBinding.java:99)
        at com.test.binding.databinding.ActivityMainBinding.inflate(ActivityMainBinding.java:80)
        at com.test.binding.databinding.ActivityMainBinding.inflate(ActivityMainBinding.java:70)
        at com.test.binding.presentation.screen.InviteActivity.onCreate(InviteActivity.java:25)
        at android.app.Activity.performCreate(Activity.java:7825)
        at android.app.Activity.performCreate(Activity.java:7814)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1306)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7356) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 

怎么了？*如果我删除包含布局的ID，则还有其他错误。

Answer 1

这是我使用视图绑定处理包含布局的方式。

// When view binding is enabled it will create a binding class for each layout, converting the file name to Pascal case. 
ActivityMainBinding binding;
IncludedLayout bindingIncludedLayout;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Inflate the layout as per google doc instructions
    binding = ActivityMainBinding.inflate(getLayoutInflater());

    // add the inflated view to the Included view. 
    bindingIncludedLayout = binding;

    setContentView(binding.getRoot());

    // binding in the main layout
    binding.myView.setText("text");

    // binding in the included layout
    bindingIncludedLayout.textview_name.("additional text")

    }

我强烈建议学习数据绑定而不是视图绑定，因为数据绑定具有更大的潜力，就像类固醇上的视图绑定一样。

这是我学习数据绑定的最佳教程。

https://www.androidhive.info/android-working-with-databinding/

现在已经几岁了，但是对于您入门还是很有帮助的。