退出時應用程序意外停止

Question

當我按下後退按鈕並需要強制關閉時，我的應用程序意外停止。以下是錯誤日誌：

11-16 14:57:34.595: E/AndroidRuntime(4899): FATAL EXCEPTION: main 
11-16 14:57:34.595: E/AndroidRuntime(4899): java.lang.IllegalStateException 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at android.media.MediaPlayer.getDuration(Native Method) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at com.example.musicshare.AndroidBuildingMusicPlayerActivity$1.run(AndroidBuildingMusicPlayerActivity.java:337) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at android.os.Handler.handleCallback(Handler.java:587) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at android.os.Handler.dispatchMessage(Handler.java:92) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at android.os.Looper.loop(Looper.java:123) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at android.app.ActivityThread.main(ActivityThread.java:3691) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at java.lang.reflect.Method.invokeNative(Native Method) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at java.lang.reflect.Method.invoke(Method.java:507) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605) 
11-16 14:57:34.595: E/AndroidRuntime(4899):  at dalvik.system.NativeStart.main(Native Method) 

可能是什麼問題？

Answer 1

見你的日誌：

11-12 14:21:20.080: E/AndroidRuntime(8843): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.musicshare/com.example.musicshare.ZoneActivity}; have you declared this activity in your AndroidManifest.xml? 

您還沒有宣佈ZoneActivity在你的Android清單..打開您的Android清單，並添加：

<activity android:name=".ZoneActivity" /> 

Answer 2

就是這樣有趣的是適合你的信息：

Unable to find explicit activity class com.example.musicshare/com.example.musicshare.ZoneActivity}; have you declared this activity in your AndroidManifest.xml?

看起來像是您的清單中定義的活動在您的代碼中不存在。