方向更改后NullPointerException

Question

使用以下代碼，我在旋轉設備時出錯。

Picasso.with(container.getContext()).load("http://image.tmdb.org/t/p/w185/" + mMovie.getPosterPath()).error(R.drawable.noimagefound).into((ImageView)rootView.findViewById(R.id.image_poster));

這只發生在我旋轉屏幕時。 如果我有一個斷點並且我調試代碼，那么它可以正常工作。 它似乎只有在它自己運行時才會中斷。

錯誤粘貼在下面：

Process: com.example.strahinja.popularmoviesp2, PID: 2942
              java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.strahinja.popularmoviesp2/com.example.strahinja.popularmoviesp2.activity.MovieListActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.view.ViewGroup.getContext()' on a null object reference
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                  at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4077)
                  at android.app.ActivityThread.-wrap15(ActivityThread.java)
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1350)
                  at android.os.Handler.dispatchMessage(Handler.java:102)
                  at android.os.Looper.loop(Looper.java:148)
                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
               Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.view.ViewGroup.getContext()' on a null object reference
                  at com.example.strahinja.popularmoviesp2.fragment.MovieDetailFragment.onCreateView(MovieDetailFragment.java:47)
                  at android.support.v4.app.Fragment.performCreateView(Fragment.java:2080)
                  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1108)
                  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1290)
                  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1272)
                  at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:2149)
                  at android.support.v4.app.FragmentController.dispatchActivityCreated(FragmentController.java:201)
                  at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:600)
                  at android.support.v7.app.AppCompatActivity.onStart(AppCompatActivity.java:178)
                  at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1237)
                  at android.app.Activity.performStart(Activity.java:6253)
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                  at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4077) 
                  at android.app.ActivityThread.-wrap15(ActivityThread.java) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1350) 
                  at android.os.Handler.dispatchMessage(Handler.java:102) 
                  at android.os.Looper.loop(Looper.java:148) 
                  at android.app.ActivityThread.main(ActivityThread.java:5417) 
                  at java.lang.reflect.Method.invoke(Native Method) 
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

有人可以告訴我我需要做些什么來解決這個問題嗎？

Answer 1

Picasso沒有拋出NullPointerException，你的代碼是。

具體來說，錯誤指向您嘗試在空對象上調用getContext() 。

在這種情況下，最可能的罪魁禍首是container.getContext() ，這意味着您的container為null。

您沒有提供設置container的代碼，但是在重新創建Activity / Fragment時，您似乎沒有更新該引用。