android sqlite database access raise lock error

Question

У меня есть служба android, из которой я пытаюсь получить доступ к базе данных sqlite. Код работает нормально, но у меня проблемы с доступом к базе данных. Я думаю, что ошибка имеет какое-то отношение к блокировке базы данных. Вот мои методы, из которых я доступ к базе данных:

private void checkWatchList() { 
    Log.i("watch list", "watch list started"); 
    Cursor cursor; 
    try { 
     cursor = dbhandler.getAlerts(); 
     if (cursor.moveToFirst()) { 
      while (cursor.moveToNext()) { 
       Log.i("watch list", "checked"); 
       String share_name = cursor.getString(cursor 
         .getColumnIndex(KEY_SHARE_NAME)); 
       String max_price = cursor.getString(cursor 
         .getColumnIndex(KEY_MAX_PRICE)); 
       String min_price = cursor.getString(cursor 
         .getColumnIndex(KEY_MIN_PRICE)); 
       int action = cursor.getInt(cursor 
         .getColumnIndex(KEY_ACTION)); 

       if (min_price.equals("NULL")) { 
        double maxprice = Double.parseDouble(max_price); 
        compareMax(share_name, maxprice, action); 
       } else if (max_price.equals("NULL")) { 
        double minprice = Double.parseDouble(min_price); 
        compareMin(share_name, minprice, action); 
       } else { 
        double maxprice = Double.parseDouble(max_price); 
        double minprice = Double.parseDouble(min_price); 
        compareMinMax(share_name, minprice, maxprice, action); 
       } 
      } 
     } 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
} 

private void compareMin(String sharename, double minprice, int action) { 
    Log.i("compare min", "compare min"); 
    Cursor cursor; 
    double new_price; 
    String message = "The price is below minimum set price"; 
    try { 
     cursor = dbhandler.compare(sharename); 
     new_price = cursor.getDouble(cursor.getColumnIndex(KEY_PRICE)); 

     if (minprice <= new_price) { 
      dbhandler.addTask(sharename, action, message); 
     } 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 

} 

private void compareMinMax(String sharename, double minprice, 
     double maxprice, int action) { 
    Log.i("compare minmax", "compare minmax"); 
    Cursor cursor; 
    String message = "This price is below minimum set price."; 
    try { 
     cursor = dbhandler.compare(sharename); 
     double new_price = cursor.getDouble(cursor 
       .getColumnIndex(KEY_PRICE)); 
     if (new_price <= minprice) { 
      dbhandler.addTask(sharename, action, message); 
     } else if (new_price >= maxprice) { 
      dbhandler.addTask(sharename, action, message); 
     } 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
} 

private void compareMax(String sharename, double maxprice, int action) { 
    Log.i("compare max", "compare max"); 
    Cursor cursor; 
    String message = "This price is more than maximum set price."; 
    try { 
     cursor = dbhandler.compare(sharename); 
     double new_price = cursor.getDouble(cursor 
       .getColumnIndex(KEY_PRICE)); 

     if (new_price >= maxprice) { 
      dbhandler.addTask(sharename, action, message); 
     } 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
} 

А вот методы из CLAS DatabaseHandler:

public Cursor getAlerts() { 
    Cursor cursor; 
    SQLiteDatabase database = this.getReadableDatabase(); 
    cursor = database.query(TABLE_ALERTS, new String[] { KEY_SHARE_NAME, 
      KEY_MIN_PRICE, KEY_MAX_PRICE, KEY_ACTION }, null, null, null, 
      null, null); 
    database.close(); 
    return cursor; 
} 

public void addTask(String name, int action, String message) { 
    SQLiteDatabase database = this.getWritableDatabase(); 
    ContentValues values = new ContentValues(); 
    values.put(KEY_SHARENAME, name); 
    values.put(KEY_TASK, action); 
    values.put(KEY_MESSAGE, message); 

    database.insert(TABLE_TASKS, null, values); 
    database.close(); 
} 

public Cursor compare(String sharename) { 
    Cursor cursor; 
    SQLiteDatabase database = this.getReadableDatabase(); 
    cursor = database.query(TABLE_SHARES, new String[] { KEY_PRICE }, 
      KEY_NAME + "=?", new String[] { sharename }, null, null, null); 
    database.close(); 
    return cursor; 
} 

С выхода в LogCat, мой код не работает до до тех пор, метод checkWatchList но не выполняет, если условие в loop.Here является выходным LogCat

09-11 13:11:15.289: I/watch list(22091): watch list started 
09-11 13:11:15.319: W/System.err(22091): java.lang.IllegalStateException: database /data/data/com.intelligent.stocktrader/databases/stocktrader.db (conn# 0) already closed 
09-11 13:11:15.329: W/System.err(22091): at android.database.sqlite.SQLiteDatabase.verifyDbIsOpen(SQLiteDatabase.java:2082) 
09-11 13:11:15.329: W/System.err(22091): at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:413) 
09-11 13:11:15.329: W/System.err(22091): at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:400) 
09-11 13:11:15.329: W/System.err(22091): at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:79) 
09-11 13:11:15.339: W/System.err(22091): at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:160) 
09-11 13:11:15.339: W/System.err(22091): at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:152) 
09-11 13:11:15.339: W/System.err(22091): at android.database.AbstractCursor.moveToPosition(AbstractCursor.java:158) 
09-11 13:11:15.349: W/System.err(22091): at android.database.AbstractCursor.moveToFirst(AbstractCursor.java:235) 
09-11 13:11:15.349: W/System.err(22091): at com.intelligent.stocktrader.database.ShareService.checkWatchList(ShareService.java:160) 
09-11 13:11:15.349: W/System.err(22091): at com.intelligent.stocktrader.database.ShareService.onCreate(ShareService.java:63) 
09-11 13:11:15.359: W/System.err(22091): at android.app.ActivityThread.handleCreateService(ActivityThread.java:2252) 
09-11 13:11:15.359: W/System.err(22091): at android.app.ActivityThread.access$1600(ActivityThread.java:122) 
09-11 13:11:15.359: W/System.err(22091): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200) 
09-11 13:11:15.369: W/System.err(22091): at android.os.Handler.dispatchMessage(Handler.java:99) 
09-11 13:11:15.369: W/System.err(22091): at android.os.Looper.loop(Looper.java:137) 
09-11 13:11:15.369: W/System.err(22091): at android.app.ActivityThread.main(ActivityThread.java:4340) 
09-11 13:11:15.369: W/System.err(22091): at java.lang.reflect.Method.invokeNative(Native Method) 
09-11 13:11:15.379: W/System.err(22091): at java.lang.reflect.Method.invoke(Method.java:511) 
09-11 13:11:15.379: W/System.err(22091): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
09-11 13:11:15.379: W/System.err(22091): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
09-11 13:11:15.379: W/System.err(22091): at dalvik.system.NativeStart.main(Native Method) 
09-11 13:11:15.389: I/LocalService(22091): Received start id 1: Intent { cmp=com.intelligent.stocktrader/.database.ShareService } 

Answer 1

Я могу копировать вставить часть моего кода для и здесь :). Надеюсь, это полезно.

 public zipAreas getzipArea(int zipAreaId) { 

    SQLiteDatabase db = _dbhelper.getReadableDatabase(); 
    Cursor c = null; 
    try { 
     zipAreas zipArea = null; 
     String[] selectionArgs = new String[1]; 
     selectionArgs[0] = Integer.toString(zipAreaId); 

     c = db.rawQuery("select * from " + TABLE_zipAreaS + " where " 
       + COLUMN_ID + " = ?", selectionArgs); 

     if (c.getCount() > 0) { 
      c.moveToFirst(); 

      zipArea = new zipAreas(c.getInt(c.getColumnIndex(COLUMN_ID)), 
        c.getString(c.getColumnIndex(COLUMN_BIZ_AREA))); 
     } 

     return zipArea; 
    } catch (Exception e) { 

     CoreDataManager.handleException(new DatabaseException(e)); 
     return null; 
    } finally { 
     if (null != c) 
      c.close(); 
    } 
} 

Answer 2

удалить database.close(); в ваших методах getAlerts и сравнить (String ул)

public Cursor getAlerts() { 
     Cursor cursor; 
     SQLiteDatabase database = this.getReadableDatabase(); 
     cursor = database.query(TABLE_ALERTS, new String[] { KEY_SHARE_NAME, 
       KEY_MIN_PRICE, KEY_MAX_PRICE, KEY_ACTION }, null, null, null, 
       null, null); 
     return cursor; 
    } 

    public void addTask(String name, int action, String message) { 
     SQLiteDatabase database = this.getWritableDatabase(); 
     ContentValues values = new ContentValues(); 
     values.put(KEY_SHARENAME, name); 
     values.put(KEY_TASK, action); 
     values.put(KEY_MESSAGE, message); 

     database.insert(TABLE_TASKS, null, values); 
     database.close(); 
    } 

    public Cursor compare(String sharename) { 
     Cursor cursor; 
     SQLiteDatabase database = this.getReadableDatabase(); 
     cursor = database.query(TABLE_SHARES, new String[] { KEY_PRICE }, 
       KEY_NAME + "=?", new String[] { sharename }, null, null, null); 
     return cursor; 
    } 

и посмотреть этот http://www.androidhive.info/2011/11/android-sqlite-database-tutorial/