當我使用SQliteDbHelper時如何解決數據庫未打開錯誤？

我已經用Activty，Service，SQLiteOpenHelper實現了一個應用程序。在我的應用程序中，我從服務類中獲取數據併發送到SQLiteOpenHelper類，該類將數據保存到SQlite數據庫中，並且正在從此SQLiteOpenHelper類通過使用SimpleCurserAdapeter然後更新到ListView的Activity類。我已經使用的碼結構，如下所示：當我使用SQliteDbHelper時如何解決數據庫未打開錯誤？

MyActivity.java：

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.testlist); 
    IntentFilter filter = new IntentFilter("com.sample.presentationLayer"); 
    registerReceiver(myReceiver, filter); 
    startService(new Intent(MyActivity.this, RepeatService.class)); 
} 
    private BroadcastReceiver myReceiver = new BroadcastReceiver() { 
     @Override 
     public void onReceive(Context context, Intent intent) { 
     objSqlite= new MySqliteHelper(MyActivity.this); 
     objSqlite.openToWrite(); 
     lst = ((ListView)findViewById(R.id.listView1)); 
     cursor = objSqlite.queueAll(); 
     getFromDB = new String[]{MySqliteHelper.KEY_CONTENT2,MySqliteHelper.KEY_CONTENT3}; 
     toView = new int[]{R.id.usrName,R.id.msgText}; 
     lst.setAdapter(new SimpleCursorAdapter(NewShoutGetMessagesScrn.this, R.layout.test, cursor, getFromDB, toView)); 
     updateList(); 

     } 
    }; 

    @Override 
protected void onDestroy() { 
    super.onDestroy(); 
    stopService(new Intent(MyActivity.this, RepeatService.class)); 
    unregisterReceiver(myReceiver); 
    if(objSqlite.isOpen) { 
    objSqlite.deleteAll(); 
    objSqlite.close(); 
} 

}

RepeatService.java：

private Timer timer = new Timer(); 
private static final long UPDATE_INTERVAL = 20000; 
private MySqliteHelper objSqlite; 

@Override 
public void onCreate() { 

    objSqlite = new MySqliteHelper(RepeatService.this); 
    objSqlite.openToWrite(); 
    pollForUpdates(); 
    super.onCreate(); 
} 


private void pollForUpdates() { 

     timer.scheduleAtFixedRate(new TimerTask() { 
     @Override 
     public void run() { 
       for(int i=0;i<result.size();i++) 
     { 

       String userID = result.get(i).getUserID(); 
     String userName = result.get(i).getName(); 
    String userMessage=result.get(i).getMessageText(); 

     objSqlite.insert(userID, userName, userMessage); 
      Intent intent = new Intent(); 
       intent.setAction("com.sample.presentationLayer"); 
       sendBroadcast(intent); // finally broadcast 
     } 
    }, 0, UPDATE_INTERVAL); 
     } 


    @Override 
public void onDestroy() { 
    timer.cancel(); 
    if(objSqlite.isOpen) { 
      objSqlite.deleteAll(); 
      objSqlite.close(); 
      } 
}

MySqliteHelper.java

private Context context; 

    public MySqliteHelper(Context c){ 
    context = c; 
    } 

public MySqliteHelper openToRead() throws android.database.SQLException { 
sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION); 
sqLiteDatabase = sqLiteHelper.getReadableDatabase(); 
return this; 
} 

public MySqliteHelper openToWrite() throws android.database.SQLException { 
sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION); 
sqLiteDatabase = sqLiteHelper.getWritableDatabase(); 
return this; 
} 

public void close(){ 
    sqLiteHelper.close(); 
} 

public long insert(String content1, String content2,String content3){ 

ContentValues contentValues = new ContentValues(); 
contentValues.put(USER_ID, content1); 
contentValues.put(USER_NAME, content2); 
contentValues.put(USER_MESSAGE, content3); 
return sqLiteDatabase.insert(MYDATABASE_TABLE, null, contentValues); 
} 

public int deleteAll(){ 
    return sqLiteDatabase.delete(MYDATABASE_TABLE, null, null); 
} 

public Cursor queueAll(){ 
String[] columns = new String[]{KEY_ID, USER_ID, USER_NAME, USER_MESSAGE}; 
Cursor cursor = sqLiteDatabase.query(MYDATABASE_TABLE, columns, 
null, null, null, null, "_id DESC"); 
cursor.moveToFirst(); 
return cursor; 
} 


public class SQLiteHelper extends SQLiteOpenHelper { 

public SQLiteHelper(Context context, String name, 
CursorFactory factory, int version) { 
super(context, name, factory, version); 
} 

@Override 
public void onCreate(SQLiteDatabase db) { 
// TODO Auto-generated method stub 
db.execSQL(SCRIPT_CREATE_DATABASE); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
// TODO Auto-generated method stub 
} 
}

}

從上面的代碼，當我從我的應用我收到一個錯誤退出：

03-01 16:11:47.468: ERROR/AndroidRuntime(3038): Uncaught handler: thread main exiting due to uncaught exception 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038): java.lang.RuntimeException: Unable to destroy activity {com.sample.presentationLayer/com.sample.presentationLayer.MyActivity}: java.lang.IllegalStateException: database not open 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3364) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3382) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.app.ActivityThread.access$2700(ActivityThread.java:116) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1826) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.os.Handler.dispatchMessage(Handler.java:99) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.os.Looper.loop(Looper.java:123) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.app.ActivityThread.main(ActivityThread.java:4203) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at java.lang.reflect.Method.invokeNative(Native Method) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at java.lang.reflect.Method.invoke(Method.java:521) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at dalvik.system.NativeStart.main(Native Method) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038): Caused by: java.lang.IllegalStateException: database not open 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.database.sqlite.SQLiteDatabase.delete(SQLiteDatabase.java:1348) 
    03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at com.fitzgerald.shoutdataLayer.MySqliteHelper.deleteAll(MySqliteHelper.java:65) 
03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at com.fitzgerald.presentationLayer.NewShoutGetMessagesScrn.onDestroy(MyActivity.java:58) 
03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3351) 
03-01 16:11:47.478: ERROR/AndroidRuntime(3038):  ... 11 more

如何解決上面的錯誤？並且定時器不取消...

來源

2012-03-01 prasad.gai

在onDestroy()方法中，首先關閉數據庫，然後嘗試刪除記錄（在活動中以及在服務中）。試試這個：

objSqlite.deleteAll(); 
objSqlite.close();

編輯： 你的問題的另一個原因可能是在你的ActivityMyActivity.java的onDestroy()方法你第一次調用：

stopService(new Intent(MyActivity.this, RepeatService.class));

調用該服務的onDestroy()方法。在該方法中，您刪除記錄，然後關閉數據庫。在此之後，您將返回到活動的onDestroy()方法，其中再次嘗試刪除記錄（但數據庫已從服務中關閉），然後再次關閉數據庫。在活動onDestroy儘量先檢查數據庫仍然嘗試刪除所有記錄之前打開：

@Override 
protected void onDestroy() { 
    super.onDestroy(); 
    stopService(new Intent(MyActivity.this, RepeatService.class)); 
    unregisterReceiver(myReceiver); 
    if(objSqlite.isOpen) { 
     objSqlite.deleteAll(); 
     objSqlite.close(); 
    } 
}

來源

2012-03-01 10:49:54 Luksprog

即使它正在發生同樣的事情 – 2012-03-01 10:58:09

@ prasad.gai你做的活動'MyActivity的變化。 java'和在服務'RepeatService'？ – Luksprog 2012-03-01 11:01:06

是的，請找到我的更新代碼 – 2012-03-01 11:04:36

當我使用SQliteDbHelper時如何解決數據庫未打開錯誤？

回答

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