AndroidAndroidStudio空指针解决之：listview与adapter的使用报空 java.lang.NullPointerException

Posted 2022-03-08 程序员小冰

作者：程序员小冰 （转载请说明出处）

博客地址：http://blog.csdn.net/qq_21376985

长期维护的android项目，里面包括常用功能实现，以及知识点详解，
当然还有Java中的知识点。具体请看github：

https://github.com/QQ986945193/DavidAndroidProjectTools

说明，因为最近在将android中常见的知识点，以及常用功能集中在一个android项目中，方便自己以后再看，并且送给初学者以及工作中的人员，以后遇到某些功能直接拿来用。所以就写了了一下listview与adapter的知识点详解，发现突然报空指针。 java.lang.NullPointerException，错误代码如下：

java.lang.NullPointerException
                                                                                                                       at android.widget.AbsListView.obtainView(AbsListView.java:2277)
                                                                                                                       at android.widget.ListView.measureHeightOfChildren(ListView.java:1263)
                                                                                                                       at android.widget.ListView.onMeasure(ListView.java:1175)
                                                                                                                       at android.view.View.measure(View.java:16497)
                                                                                                                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                                                                                                                       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:16497)
                                                                                                                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                                                                                                                       at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                                                                                                                       at android.view.View.measure(View.java:16497)
                                                                                                                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                                                                                                                       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:16497)
                                                                                                                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                                                                                                                       at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                                                                                                                       at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
                                                                                                                       at android.view.View.measure(View.java:16497)
                                                                                                                       at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1912)
                                                                                                                       at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1109)
                                                                                                                       at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1291)
                                                                                                                       at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)
                                                                                                                       at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)
                                                                                                                       at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
                                                                                                                       at android.view.Choreographer.doCallbacks(Choreographer.java:574)
                                                                                                                       at android.view.Choreographer.doFrame(Choreographer.java:544)
                                                                                                                       at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
                                                                                                                       at android.os.Handler.handleCallback(Handler.java:733)
                                                                                                                       at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                                                       at android.os.Looper.loop(Looper.java:136)
                                                                                                                       at android.app.ActivityThread.main(ActivityThread.java:5001)
                                                                                                                       at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                                                       at java.lang.reflect.Method.invoke(Method.java:515)
                                                                                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
                                                                                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
                                                                                                                       at dalvik.system.NativeStart.main(Native Method)

最后仔细看了一下，原来是adapter中的getView();我直接写了返回为null，所以改完之后，就OK了。

当然如果帮到了你，欢迎点赞。小问题。