方法未定义？

Question

When I write the code below, it says that the method getReadableDatabase() is undefined for dbHelper , what is the problem with it?

public void checklogin(String logged){


    DatabaseAdapter dbHelper = new DatabaseAdapter(LoginActivity.this);

    db = dbHelper.getReadableDatabase();


    Cursor mCursor = db.query(dbHelper.TABLE_USERS,new String[]{"select * from users"}, " Name like" + "'logged+'",null,null,null,null);

     if  (mCursor.moveToFirst()){
         Toast.makeText(LoginActivity.this, "Yaaaay", Toast.LENGTH_LONG).show();
     }

      Toast.makeText(LoginActivity.this, "invalid", Toast.LENGTH_LONG).show();


        }
}

Answer 1

What's your implementation of DatabaseAdapter ? It's not part of the Android framework. The only class that I know of that implements getReadableDatabase() is SQLiteOpenHelper .

Answer 2

这通常意味着getReadableDatabase（）不是您的DatabaseAdapter类中的函数。