Android 如何找到正在崩溃的RecyclerView

我有一个大约10个RecyclerViews的应用程序。我的一个用户正在经历一个崩溃，它抛出了以下堆栈跟踪。但问题是当我要求用户解释时。他声称看到坠机的地方很奇怪，因为附近没有RecyclerView或ListView。如何确定哪个RecyclerView导致此问题？这是我从坠机报告中得到的线索

Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v7.widget.RecyclerView$LayoutManager.canScrollVertically()' on a null object reference
       at android.support.v7.widget.RecyclerView.computeVerticalScrollOffset(RecyclerView.java:1613)
       at android.view.View.canScrollVertically(View.java:12835)
       at android.support.v4.view.ViewCompatICS.canScrollVertically(ViewCompatICS.java:35)
       at android.support.v4.view.ViewCompat$ICSViewCompatImpl.canScrollVertically(ViewCompat.java:1253)
       at android.support.v4.view.ViewCompat.canScrollVertically(ViewCompat.java:1695)
       at android.support.v4.widget.SwipeRefreshLayout.canChildScrollUp(SwipeRefreshLayout.java:643)
       at android.support.v4.widget.SwipeRefreshLayout.onInterceptTouchEvent(SwipeRefreshLayout.java:657)
       at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1960)
       at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405)
       at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049)
       at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405)
       at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049)
       at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405)
       at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049)
       at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405)
       at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049)
       at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405)
       at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2049)
       at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2369)
       at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1719)
       at android.app.Activity.dispatchTouchEvent(Activity.java:2742)
       at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2330)
       at android.view.View.dispatchPointerEvent(View.java:8666)
       at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4123)
       at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3989)
       at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3544)
       at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3597)
       at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3563)
       at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3680)
       at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3571)
       at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3737)
       at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3544)
       at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3597)
       at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3563)
       at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3571)
       at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3544)
       at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5807)
       at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5781)
       at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5752)
       at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:5897)
       at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
       at android.os.MessageQueue.nativePollOnce(MessageQueue.java)
       at android.os.MessageQueue.next(MessageQueue.java:143)
       at android.os.Looper.loop(Looper.java:122)
       at android.app.ActivityThread.main(ActivityThread.java:5254)
       at java.lang.reflect.Method.invoke(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

---

在每个适配器中放入

Log.d

指令，并检查de LogCat

private static final String LOGTAG = "Logs";


 Log.d(LOGTAG, "MSG");

但你的错误是：

Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v7.widget.RecyclerView$LayoutManager.canScrollVertically()' on a null object reference

如果您在LinearLayoutManager和RecyclerView中更改此项，将修复：

LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
    layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
    recyclerView.setLayoutManager(layoutManager);

使用适配器前：

recyclerView.setAdapter(adapter);

---

java.lang.NullPointerException:
如果试图使用任何未初始化的对象，将抛出


简单示例：

假设您有一个名为ClassA的类，它有一个名为myFunction（）的函数

下面是将引发异常的错误代码

ClassA objectA;
objectA.myFunction();

由于您没有初始化objectA中的任何内容（当前为null），因此它会抛出
java.lang.NullPointerException:

因此，正确的代码是

ClassA objectA=new ClassA();
objectA.myFunction();


现在它可以工作了。。像这样，您可能会错过任何类（例如RecyclerView、Adapter或LinearLayout）的一些初始化。这就是这个例外的解释。希望你能理解

如果无法识别您的错误所在，请使用
Log.d（“我的标签”，“此处有一些文本”）在每行（或每5行）之间。查找未执行的日志，应该有问题

祝你好运。。（：
这是有道理的。所以+1。我会在几天后知道它是否有效。谢谢。