Question

当我使用 Android数据绑定在我的xml文件中的非根元素中使用include标记时，应用程序崩溃了。但是，当include标记放在根元素中或没有数据绑定时，该应用程序可以正常工作。

这是我的源代码，任何人都可以帮我弄清楚原因吗？

activity_main.xml中

<layout>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".MainActivity">


        <TextView
            android:id="@+id/text_view"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/hello_world" />

        <LinearLayout

            android:layout_width="match_parent"
            android:layout_height="match_parent">

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

        </LinearLayout>
    </LinearLayout>
</layout>

MainActivity.java

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        binding.textView.setText("hello world");
    }
}

堆栈跟踪

I/ActivityManager(13254): START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.liangfeizc.databindings/.MainActivity (has extras)} from uid 10008 on display 0
I/ActivityManager(13254): Start proc com.liangfeizc.databindings for activity com.liangfeizc.databindings/.MainActivity: pid=18181 uid=10065 gids={50065, 9997} abi=x86
I/art     (18181): Not late-enabling -Xcheck:jni (already on)
D/AndroidRuntime(18181): Shutting down VM
E/AndroidRuntime(18181): FATAL EXCEPTION: main
E/AndroidRuntime(18181): Process: com.liangfeizc.databindings, PID: 18181
E/AndroidRuntime(18181): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.liangfeizc.databindings/com.liangfeizc.databindings.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.LinearLayout.setTag(java.lang.Object)' on a null object reference
E/AndroidRuntime(18181):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
E/AndroidRuntime(18181):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
E/AndroidRuntime(18181):  at android.app.ActivityThread.access$800(ActivityThread.java:144)
E/AndroidRuntime(18181):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
E/AndroidRuntime(18181):  at android.os.Handler.dispatchMessage(Handler.java:102)
E/AndroidRuntime(18181):  at android.os.Looper.loop(Looper.java:135)
E/AndroidRuntime(18181):  at android.app.ActivityThread.main(ActivityThread.java:5221)
E/AndroidRuntime(18181):  at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(18181):  at java.lang.reflect.Method.invoke(Method.java:372)
E/AndroidRuntime(18181):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
E/AndroidRuntime(18181):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
E/AndroidRuntime(18181): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.LinearLayout.setTag(java.lang.Object)' on a null object reference
E/AndroidRuntime(18181):  at com.liangfeizc.databindings.databinding.ActivityMainBinding.<init>(ActivityMainBinding.java:27)
E/AndroidRuntime(18181):  at com.liangfeizc.databindings.databinding.ActivityMainBinding.bind(ActivityMainBinding.java:88)
E/AndroidRuntime(18181):  at android.databinding.DataBinderMapper.getDataBinder(DataBinderMapper.java:14)
E/AndroidRuntime(18181):  at android.databinding.DataBindingUtil.bind(DataBindingUtil.java:107)
E/AndroidRuntime(18181):  at android.databinding.DataBindingUtil.inflate(DataBindingUtil.java:68)
E/AndroidRuntime(18181):  at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:185)
E/AndroidRuntime(18181):  at com.liangfeizc.databindings.MainActivity.onCreate(MainActivity.java:18)
E/AndroidRuntime(18181):  at android.app.Activity.performCreate(Activity.java:5937)
E/AndroidRuntime(18181):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
E/AndroidRuntime(18181):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
E/AndroidRuntime(18181):  ... 10 more
W/ActivityManager(13254):   Force finishing activity com.liangfeizc.databindings/.MainActivity
D/        (13254): HostConnection::get() New Host Connection established 0xa0a234d0, tid 13352

Answer 1

报告在这里： https://code.google.com/p/android/issues/detail?id=176649

内部修正，应尽快释放。

Answer 2

我在使用include标记时遇到问题，而不是代码。我建议使用片段而不是它们是可靠的并且是更好的编程方式。创建包含在片段中的文件，然后在布局文件中调用片段，如下所示

<fragment android:name="your fragment here"
          android:id="@+id/article_fragment"
          android:layout_weight="2"
          android:layout_width="0dp"
          android:layout_height="match_parent" />

我建议点击google获取片段，然后填写剩下的部分。

在非根ViewGroup中使用include标记时，Android数据绑定会导致应用程序崩溃

2 个答案: