android - 在 android 8 上使用 android 数据绑定(bind)时应用程序崩溃

Question

代码在 oreo 之前的设备上工作，但 Crashlytics 说它在安卓 8 设备

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getAppComponent().inject(this);
        binding = DataBindingUtil.setContentView(this, R.layout.main_activity);
    }

堆栈跟踪

java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.ViewGroup.getChildCount()' on a null object reference

Caused by java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.ViewGroup.getChildCount()' on a null object reference
       at android.databinding.DataBindingUtil.bindToAddedViews(DataBindingUtil.java:295)
       at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:279)
       at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:261)
       at com.myapp.MyActivity.onCreate(MyActivity.java:59)
       at android.app.Activity.performCreate(Activity.java:7174)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1220)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2910)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3032)
       at android.app.ActivityThread.-wrap11(Unknown Source)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1696)
       at android.os.Handler.dispatchMessage(Handler.java:105)
       at android.os.Looper.loop(Looper.java:164)
       at android.app.ActivityThread.main(ActivityThread.java:6940)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)

Answer 1

在 8 上有类似的崩溃和完全相同的堆栈跟踪。

您是否尝试过使用:

binding = DataBindingUtil.inflate(getLayoutInflater(), R.layout.activity, null, false);
setContentView(binding.getRoot());

上面代码和调用的区别

DataBindingUtil.setContentView(...);

是 inflate() 直接返回一个 View，然后传递给 DataBindingUtils::bindToAddedViews。如果是 DataBindingUtil.setContentView，则使用以下逻辑

activity.setContentView(layoutId);
View decorView = activity.getWindow().getDecorView();
ViewGroup contentView = (ViewGroup) decorView.findViewById(android.R.id.content);

似乎是

ViewGroup contentView = (ViewGroup) decorView.findViewById(android.R.id.content);

只是 NULL...