如何使用sqlite检索单个结果？

Question

I have this code that retrieves the last id

 public int retrieveLastId() {

            SQLiteDatabase db = this.getWritableDatabase();
            Cursor cursor = db.rawQuery("select "+ RECORDING_ID +" from " + DATABASE_TABLE + " ORDER BY "+ RECORDING_ID +" DESC LIMIT 1 ", null);


            int last = 0;
            last = Integer.parseInt(cursor.getString(0));
            Log.e("sfsdlkfjs dfl sd",cursor.getString(0));
            return  last;
        } 

but I get an error android.database.cursorindexoutofboundsexception how do I return the last id properly?

Answer 1

This cause of error is you do not check cursor is null .

if (cursor.moveToFirst()) // Check your cursor has value?
   System.out.println(cursor.getString(0); 

cursor.close();    //you should realse cursor 

Answer 2

Make sure you have values in the table. If it doesn't have it will end up with exception with your code.

Try doing this changes in your code.

Cursor cursor = database.rawQuery(selectQuery, null);if(cursor!=null && cursor.getCount()>0){cursor.moveToFirst()
    do{
        bankbalresult = cursor.getString(0);
    } while (cursor.moveToNext());}