尝试从空对象引用上的字段'android.view.View androidx.recyclerview.widget.RecyclerView$b0.a'读取

Question

我正在开发一款应用程序，它可以扫描BLE并更新回收器视图。该应用程序在安卓工作室的调试模式下运行完全正常。但当我在play store上发布生产版时，它会崩溃，并出现以下错误(来自crashlytics(。。

Fatal Exception : java.lang.NullPointerException: Attempt to read from field 'android.view.View androidx.recyclerview.widget.RecyclerView$b0.a' on a null object reference
at androidx.recyclerview.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:59)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:59)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:3)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:3)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:2)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:17)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:2)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:7)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:2)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:66)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at androidx.coordinatorlayout.widget.CoordinatorLayout.layoutChild(CoordinatorLayout.java:15)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:4)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at androidx.appcompat.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:49)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:831)
at android.view.View.layout(View.java:22900)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3619)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:3087)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:2060)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8421)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:972)
at android.view.Choreographer.doCallbacks(Choreographer.java:796)
at android.view.Choreographer.doFrame(Choreographer.java:731)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:957)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:250)
at android.app.ActivityThread.main(ActivityThread.java:7886)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:970)

我正在尝试这个解决方案，但遇到了同样的问题。

这是视图持有者通用类：

@Override
public V onCreateViewHolder(ViewGroup parent,
int viewType) {. ///
// create a new view
View v = LayoutInflater.from(parent.getContext()).inflate(viewResId, parent, false);
Class[] args = new Class[1];
args[0] = View.class;
try {
return holderClass.getDeclaredConstructor(args).newInstance(v);
} catch (Exception e) {
if (e != null && e.getMessage() != null) {
AppLogger.e(RecyclerListAdapter.class.getSimpleName(), e.getMessage());
e.printStackTrace();
}
return null;
}
}

Answer 1

问题是在未指定ProGuard规则的情况下将.aab文件上载到控制台。

你可以在这里阅读更多信息https://developer.android.com/studio/build/shrink-code