Exception异常报错问题解决笔记

1、java.lang.NullPointerException: Attempt to invoke virtual method ‘android.content.res.AssetManager android.content.res.Resources.getAssets()’ on a null object reference抛出这个错误是在安装apk的时候就黑屏了，刚开始百思不得其解，明明还没有调用getAssets()就一直抛出这个异常，各种加日志加注释没找到问题所在。最后既然提示这个android.content.res.Resources为空，就在Application的onCreate()加判断发现getResource确实为空

RuntimeException: Unable to start activity ComponentInfo{com.../com...activity.SignInActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.AssetManager android.content.res.Resources.getAssets()' on a null object reference    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)    at android.app.ActivityThread.access$800(ActivityThread.java:151)    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)    at android.os.Handler.dispatchMessage(Handler.java:102)    at android.os.Looper.loop(Looper.java:135)    at android.app.ActivityThread.main(ActivityThread.java:5254)    at java.lang.reflect.Method.invoke(Native Method)    at java.lang.reflect.Method.invoke(Method.java:372)    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.AssetManager android.content.res.Resources.getAssets()' on a null object reference    at android.app.LoadedApk.getAssets(LoadedApk.java:528)    at android.app.LoadedApk.makeApplication(LoadedApk.java:584)    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2243)    ... 10 more//解决方法：在Application的onCreate()加判断，getResource()为空的时候杀死当前进程    if (null == getResources()){        System.out.println("---********----------killProcess----2----***********---");        Process.killProcess(Process.myPid());    }

2、The content of the adapter has changed but ListView did not receive a notification，listview中adapter绑定的数据发生变化的时候UI还没更新就点击item就会抛出这个异常崩溃


选择类别的时候碰到列表崩溃

java.lang.IllegalStateException: The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread. Make sure your adapter calls notifyDataSetChanged() when its content changes. [in ListView(2131427470, class android.widget.ListView) with Adapter(class com..adapter.ExportVideoAdapter)]    at android.widget.ListView.layoutChildren(ListView.java:1562)    at android.widget.AbsListView$FlingRunnable.run(AbsListView.java:4498)    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:773)    at android.view.Choreographer.doCallbacks(Choreographer.java:586)    at android.view.Choreographer.doFrame(Choreographer.java:555)    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:759)    at android.os.Handler.handleCallback(Handler.java:739)    at android.os.Handler.dispatchMessage(Handler.java:95)    at android.os.Looper.loop(Looper.java:135)    at android.app.ActivityThread.main(ActivityThread.java:5254)    at java.lang.reflect.Method.invoke(Native Method)    at java.lang.reflect.Method.invoke(Method.java:372)    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)    at Android.MODEL(msm8909)    at Android.VERSION(5.1.1)    at Android.FINGERPRINT(qcom/msm8909/msm8909:5.1.1/LMY47V/icar09111534:userdebug/test-keys)//解决方法：在list数据改变的时候在主UI线程调用adapter的notifyDataSetChanged()通知数据改变了要更新UI，在//notifyDataSetChanged()之前调用listview.setVisibility(View.GONE)之后调用 //listview.setVisibility(View.VISIBLE);//代码如下：listview.setVisibility(View.GONE);adapter.notifyDataSetChanged();listview.setVisibility(View.VISIBLE);

3.在维护一个比较老的项目的时候，发现一个问题，在发出请求的时候去切换网络APP崩溃了，看抛出的异常内容被消耗了，其实是EntityUtils.toString调用了两次，response只能一次消耗完,不能多次读取。

解决方法：直接使用trycacth抛出异常，或者保存response值，每次请求赋值，通过保存的response取值。

java.lang.IllegalStateException: Content has been consumed    at org.apache.http.entity.BasicHttpEntity.getContent(BasicHttpEntity.java:89)    at org.apache.http.conn.BasicManagedEntity.getContent(BasicManagedEntity.java:105)    at org.apache.http.util.EntityUtils.toString(EntityUtils.java:117)    at org.apache.http.util.EntityUtils.toString(EntityUtils.java:151)    at net.babelstar.common.http.AbstractAsyncResponseListener.onResponseReceived(AbstractAsyncResponseListener.java:57)    at net.babelstar.common.http.AsyncHttpSender.onPostExecute(AsyncHttpSender.java:117)    at net.babelstar.common.http.AsyncHttpSender.onPostExecute(AsyncHttpSender.java:1)    at android.os.AsyncTask.finish(AsyncTask.java:651)    at android.os.AsyncTask.access$500(AsyncTask.java:180)    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)    at android.os.Handler.dispatchMessage(Handler.java:102)    at android.os.Looper.loop(Looper.java:158)    at android.app.ActivityThread.main(ActivityThread.java:7231)    at java.lang.reflect.Method.invoke(Native Method)    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)