Question

每当我尝试使用函数writeAll（ArrayList liste）保存某些东西时，应用程序崩溃。这是日志：

`E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.naabi.listeserie, PID: 3459
                  java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.FileOutputStream android.content.Context.openFileOutput(java.lang.String, int)' on a null object reference
                      at com.example.naabi.listeserie.dao.SerialisationSerieDAO.writeAll(SerialisationSerieDAO.java:58)
                      at com.example.naabi.listeserie.descriptionMrRobot.onSaveInstanceState(descriptionMrRobot.java:260)
                      at android.app.Activity.performSaveInstanceState(Activity.java:1414)
                      at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1300)
                      at android.app.ActivityThread.callCallActivityOnSaveInstanceState(ActivityThread.java:4541)
                      at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4492)
                      at android.app.ActivityThread.-wrap19(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1483)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6119)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)`

我尝试通过倾斜手机来使用该功能。

Answer 1

SerialisationSerieDAO pojo不是活动。因此，您的上下文（contexte）此案例从未初始化。使用mutator设置上下文。或者在构造函数中传递一个。

尝试调用虚方法＆＃39; java.io.FileOutputStream android.content.Context.openFileOutput（java.lang.String，int）＆＃39;在null对象上

1 个答案: