我需要在onSaveInstanceState（）方法中保存多少東西？

Question

我有2 Activities 1主菜單和另一個遊戲窗口。

的問題是，當手機的home鍵被按下前測「遊戲窗口」 Activity去onStop()方法，在這一點上都可以，但是當我回到我的應用程序崩潰。

我研究了這個問題，我認爲它與保存mplayer對象的狀態有關，因爲日誌說了什麼，我試圖保存mplayer對象的狀態，但應用程序仍然有同樣的問題。

我需要保存測試視圖的所有變量嗎？我很感激幫助。

第二活動

public class pretest extends Activity { 
private MediaPlayer mplayer; 

/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 

requestWindowFeature(Window.FEATURE_NO_TITLE); 
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.Layou  tParams.FLAG_FULLSCREEN); 
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); 
Toast.makeText(this, "onCreate2", Toast.LENGTH_SHORT).show(); 
if(mplayer!=null){mplayer.release();} 

    mplayer=MediaPlayer.create(this, R.raw.forest); 

View test = new test(this); 
mplayer.seekTo(0); 
mplayer.setLooping(true); 
mplayer.start(); 

    setContentView(test); 
    } 

     @Override 
    public boolean onKeyDown(int keyCode, KeyEvent event) { 
    if (keyCode == KeyEvent.KEYCODE_BACK) { 
     mostrarSalir(); 
     return true; 
    } 
    return super.onKeyDown(keyCode, event); 
} 


     @Override 
    public void onStart(){ 
super.onStart(); 

Toast.makeText(this, "onStart2", Toast.LENGTH_SHORT).show(); 
     } 

    @Override 
    public void onStop(){ 
super.onStop(); 

Toast.makeText(this, "onStop2", Toast.LENGTH_SHORT).show(); 
      } 

    @Override 
    public void onRestart(){ 
super.onRestart(); 

Toast.makeText(this, "onRestart2", Toast.LENGTH_SHORT).show(); 
    } 

    @Override 
    public void onDestroy(){ 
super.onDestroy(); 

Toast.makeText(this, "onDestroy2", Toast.LENGTH_SHORT).show(); 
    } 



@Override 
    public void onPause(){ 
super.onPause(); 
Toast.makeText(this, "onPause2", Toast.LENGTH_SHORT).show(); 
//LIBERA A MEDIA PLAYER 
if(mplayer!=null){mplayer.release();} 

    } 

    private void mostrarSalir(){ 
    AlertDialog.Builder dialog = new AlertDialog.Builder(this); 

    dialog.setMessage("¿Desea Regresar al menu principal?"); 
    dialog.setCancelable(false); 
    dialog.setPositiveButton("Si", new DialogInterface.OnClickListener() { 

    @Override 
    public void onClick(DialogInterface dialog, int which) { 


     finish(); 



    } 
    }); 
    dialog.setNegativeButton("No", new DialogInterface.OnClickListener() { 

    @Override 
    public void onClick(DialogInterface dialog, int which) { 


    Toast toast1 = 
        Toast.makeText(getApplicationContext(), 
          ":D!", Toast.LENGTH_SHORT); 

       toast1.show(); 

    dialog.cancel(); 

    } 
}); 
    dialog.show(); 
} 

    @Override 
    public void onResume(){ 


super.onResume(); 
//reinicia 
Toast.makeText(this, "onResume2", Toast.LENGTH_SHORT).show(); 
mplayer.seekTo(0); 
    mplayer.start(); 

    } 

    @Override 
    protected void onSaveInstanceState(Bundle estadoguardado){ 

super.onSaveInstanceState(estadoguardado); 
if(mplayer!=null){ 

    int pos=mplayer.getCurrentPosition(); 
    estadoguardado.putInt("posicion", pos); 
} 

    } 

    @Override  
    protected void onRestoreInstanceState(Bundle estadoguardado) 
    { 

    super.onRestoreInstanceState(estadoguardado); 


if(estadoguardado!=null&&mplayer!=null){ 
int pos=estadoguardado.getInt("posicion"); 
mplayer.seekTo(pos); 

     } 

    } 

    } 

錯誤日誌的代碼：

05-08 02:55:32.036: E/AndroidRuntime(7904): FATAL EXCEPTION: main 
    05-08 02:55:32.036: E/AndroidRuntime(7904): java.lang.RuntimeException: Unable to  resume activity {com.example.brain/com.example.brain.pretest}:        java.lang.IllegalStateException 
    05-08 02:55:32.036: E/AndroidRuntime(7904):  at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2214) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2229) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1019) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at android.os.Handler.dispatchMessage(Handler.java:130) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at android.os.Looper.loop(SourceFile:351) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at android.app.ActivityThread.main(ActivityThread.java:3814) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at java.lang.reflect.Method.invokeNative(Native Method) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at java.lang.reflect.Method.invoke(Method.java:538) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901) 
05-08 02:55:32.036: E/AndroidRuntime(7904): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:659) 
    05-08 02:55:32.036: E/AndroidRuntime(7904): at dalvik.system.NativeStart.main(Native Method) 
05-08 02:55:32.036: E/AndroidRuntime(7904): Caused by: java.lang.IllegalStateException 
05-08 02:55:32.036: E/AndroidRuntime(7904): at android.media.MediaPlayer.seekTo(Native Method) 
    05-08 02:55:32.036: E/AndroidRuntime(7904): at com.example.brain.pretest.onResume(pretest.java:135) 
    05-08 02:55:32.036: E/AndroidRuntime(7904): at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1189) 
    05-08 02:55:32.036: E/AndroidRuntime(7904): at android.app.Activity.performResume(Activity.java:3896) 
    05-08 02:55:32.036: E/AndroidRuntime(7904): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2204) 
05-08 02:55:32.036: E/AndroidRuntime(7904): ... 10 more 

Answer 1

在你的onPause你釋放MediaPlayer。這樣就釋放了它在子系統中鏈接的所有資源。

這應該是這樣的：

@Override 
public void onPause() 
{ 
    super.onPause(); 
    Toast.makeText(this, "onPause2", Toast.LENGTH_SHORT).show(); 
    //LIBERA A MEDIA PLAYER 
    if (mplayer != null) 
    { 
     mplayer.release(); 
     mplayer = null; 
    } 

} 

但改變你的簡歷至：

@Override 
public void onResume() 
{ 


    super.onResume(); 
    //reinicia 
    Toast.makeText(this, "onResume2", Toast.LENGTH_SHORT).show(); 
    if (mplayer == null) 
     mplayer = MediaPlayer.create(this, R.raw.forest); 
    mplayer.seekTo(0); 
    mplayer.setLooping(true); 
    mplayer.start(); 
} 

你可以調整這個多一點，因爲你實際上應該在onStoprelease並在onStart創建。

然後你pause在和play在onStart這樣你保留的引用，除非你真的離開了應用程序。應該使得前進和後退更平穩。