原因NullPointerException异常android.support.v7.widget.RecyclerView.onMeasure [英] Cause for NullPointerException android.support.v7.widget.RecyclerView.onMeasure

问题描述

我收到以下异常

11月1号至27日：15：15.756 18348-18348 / com.example.pnimje.newswipelistview   E / AndroidRuntime：致命异常：主要       显示java.lang.NullPointerException               在android.support.v7.widget.RecyclerView.onMeasure（RecyclerView.java:1764）               在android.view.View.measure（View.java:15848）               在android.widget.RelativeLayout.measureChildHorizo​​ntal（RelativeLayout.java:728）               在android.widget.RelativeLayout.onMeasure（RelativeLayout.java:477）               在android.view.View.measure（View.java:15848）               在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5008）               在android.widget.FrameLayout.onMeasure（FrameLayout.java:310）               在android.view.View.measure（View.java:15848）               在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5008）               在android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure（ActionBarOverlayLayout.java:453）               在android.view.View.measure（View.java:15848）               在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5008）               在android.widget.FrameLayout.onMeasure（FrameLayout.java:310）               在android.view.View.measure（View.java:15848）               在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5008）               在android.widget.LinearLayout.measureChildBeforeLayout（LinearLayout.java:1404）               在android.widget.LinearLayout.measureVertical（LinearLayout.java:695）               在android.widget.LinearLayout.onMeasure（LinearLayout.java:588）               在android.view.View.measure（View.java:15848）               在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5008）               在android.widget.FrameLayout.onMeasure（FrameLayout.java:310）               在com.android.internal.policy.impl.PhoneWindow $ DecorView.onMeasure（PhoneWindow.java:2189）               在android.view.View.measure（View.java:15848）               在android.view.ViewRootImpl.performMeasure（ViewRootImpl.java:1905）               在android.view.ViewRootImpl.measureHierarchy（ViewRootImpl.java:1104）               在android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:1284）               在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1004）               在android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:5481）               在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:749）               在android.view.Choreographer.doCallbacks（Choreographer.java:562）               在android.view.Choreographer.doFrame（Choreographer.java:532）               在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:735）               在android.os.Handler.handleCallback（Handler.java:730）               在android.os.Handler.dispatchMessage（Handler.java:92）               在android.os.Looper.loop（Looper.java:137）               在android.app.ActivityThread.main（ActivityThread.java:5103）               在java.lang.reflect.Method.invokeNative（本机方法）               在java.lang.reflect.Method.invoke（Method.java:525）               在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:737）               在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:553）               在dalvik.system.NativeStart.main（本机方法）

01-27 11:15:15.756 18348-18348/com.example.pnimje.newswipelistview E/AndroidRuntime﹕ FATAL EXCEPTION: main java.lang.NullPointerException at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:1764) at android.view.View.measure(View.java:15848) at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728) at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477) at android.view.View.measure(View.java:15848) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at android.view.View.measure(View.java:15848) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008) at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453) at android.view.View.measure(View.java:15848) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at android.view.View.measure(View.java:15848) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) at android.view.View.measure(View.java:15848) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189) at android.view.View.measure(View.java:15848) at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1905) at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1104) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1284) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) at android.view.Choreographer.doCallbacks(Choreographer.java:562) at android.view.Choreographer.doFrame(Choreographer.java:532) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) at android.os.Handler.handleCallback(Handler.java:730) at android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:5103) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:525) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) at dalvik.system.NativeStart.main(Native Method)

和RecyclerView.java:1764是

and RecyclerView.java:1764 is

    mLayout.onMeasure(mRecycler, mState, widthSpec, heightSpec);

为什么mLayout（布局管理）空？

why is mLayout (LayoutManager) null?

推荐答案

因为你还没有设置LinearLayoutManager为RecyclerView。

because you have not set LinearLayoutManager to RecyclerView.

例如：

    mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
    LinearLayoutManager layoutManager = new LinearLayoutManager(context);
    mRecyclerView.setLayoutManager(layoutManager);
    mRecyclerView.setAdapter(new CustomAdapter());

这篇关于原因NullPointerException异常android.support.v7.widget.RecyclerView.onMeasure的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！