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Question

當我在使用getPesoCount()像：

Log.v("SQL", String.valueOf(getPesoCount())); 

我得到一個錯誤：

FATAL EXCEPTION: main
java.lang.IllegalStateException: attemp to re-open an already-closed object: android.database.sqlite.SQLiteQuery(mSql = SELECT * FROM pesoTable)...

public void addPeso(int peso, String date) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ContentValues values = new ContentValues(); 
     values.put(KEY_PESO, peso); // Contact Name 
     values.put(KEY_DATE, date); // Contact Phone Number 

     // Inserting Row 
     db.insert(TABLE_PESO, null, values); 
     Log.v("SQL", String.valueOf(getPesoCount())); 
     db.close(); // Closing database connection 

    } 


    public int getPesoCount() { 
     String countQuery = "SELECT * FROM " + TABLE_PESO; 
     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.rawQuery(countQuery, null); 
     cursor.close(); 

     // return count 
     return cursor.getCount(); 
    } 

如果我不使用getPesoCount()，不會發生錯誤。

有人可以幫助我嗎？

Answer 1

attempt to re-open an already-closed object: 

異常告訴你很多！

如果你想使用cursor進一步不要撥打電話cursor.close();當你確定你不需要它了。

Answer 2

public void addPeso(int peso, String date) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ContentValues values = new ContentValues(); 
     values.put(KEY_PESO, peso); // Contact Name 
     values.put(KEY_DATE, date); // Contact Phone Number 

     // Inserting Row 
     db.insert(TABLE_PESO, null, values); 
     Log.v("SQL", String.valueOf(getPesoCount(db))); 
     db.close(); // Closing database connection 

    } 




    public int getPesoCount(db) { 
     String countQuery = "SELECT * FROM " + TABLE_PESO; 
     Cursor cursor = db.rawQuery(countQuery, null); 
     int count = cursor.getCount(); 
     cursor.close(); 
     return count; 
    }