RecyclerView的坑
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recycleView.setLayoutManager(layoutManager);这一行报空指针
错误信息:
FATAL EXCEPTION: main Process: com.create.bicdroid, PID: 4997 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.defaultOnMeasure(int, int)' on a null object reference at android.support.v7.widget.RecyclerView$LayoutManager.onMeasure(RecyclerView.java:8144) at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:2614) at android.view.View.measure(View.java:18948) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1486) at android.widget.LinearLayout.measureVertical(LinearLayout.java:765) at android.widget.LinearLayout.onMeasure(LinearLayout.java:647) at com.zhy.autolayout.AutoLinearLayout.onMeasure(AutoLinearLayout.java:43) at android.view.View.measure(View.java:18948) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135) at android.view.View.measure(View.java:18948) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1486) at android.widget.LinearLayout.measureVertical(LinearLayout.java:765) at android.widget.LinearLayout.onMeasure(LinearLayout.java:647) at android.view.View.measure(View.java:18948) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) at com.zhy.autolayout.AutoFrameLayout.onMeasure(AutoFrameLayout.java:64) at android.view.View.measure(View.java:18948) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1486) at android.widget.LinearLayout.measureVertical(LinearLayout.java:765) at android.widget.LinearLayout.onMeasure(LinearLayout.java:647) at com.zhy.autolayout.AutoLinearLayout.onMeasure(AutoLinearLayout.java:43) at android.view.View.measure(View.java:18948) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2713) at android.view.View.measure(View.java:18948) at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2158) at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1252) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1488) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1143) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6256) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:886) at android.view.Choreographer.doCallbacks(Choreographer.java:698) at android.view.Choreographer.doFrame(Choreographer.java:633) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:872) at android.os.Handler.handleCallback(Handler.java:743) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:150) at android.app.ActivityThread.main(ActivityThread.java:5665) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:822) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:712)
是在onmesure()方法中报错,网上解释的比较合理的原因是 这句代码必须是oncreate方法中调用,因为要计算空间尺寸,但是别的类也是同样的用法,就不会出现该错误。