Ndtyjky

I'm trying to access a row in my database from MainActivity in the following fashion. I'd like to know a better way to do this since this crashes my app with the error every time. Even after cold rebooting and wiping data.

"23:06 Emulator: glTexImage2D: got err pre :( 0x502 internal 0x1908 format 0x1908 type 0x1401

I assume there is a better way to do this. I'm calling a method which takes a User object which is stored in my database presumably at index 1. (first place in database)

 if(myDb.isNotEmpty() == true) {

                    MyProgress.calculateBalance***(myDb.getUser(1));***

this is my getUser method.

public User getUser(int id) {

        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.query(TABLE_NAME, // a. table

                COLUMNS, // b. column names

                " id = ?", // c. selections

                new String { String.valueOf(id) }, // d. selections args

                null, // e. group by

                null, // f. having

                null, // g. order by

                null); // h. limit



        if (cursor != null)

            cursor.moveToFirst();



        User user = new User();

        user.setId(Integer.parseInt(cursor.getString(0)));

        user.setWeight (Integer.parseInt(cursor.getString(1)));

        user.setAge(Integer.parseInt(cursor.getString(2)));



        return user;

    }

The last part of your method should look like this:

if ((cursor != null) && (cursor.moveToFirst()) {

    User user = new User();    

    user.setId(Integer.parseInt(cursor.getString(0)));

    user.setWeight (Integer.parseInt(cursor.getString(1)));

    user.setAge(Integer.parseInt(cursor.getString(2)));

    return user;

} else {

    return null;

}

This code ensures that the if the cursor returned is null or does not contain at least 1 row, it will not throw an error.

In this case the method will return null.

Of course if the cursor is prepared with no errors and myDB is properly initialized there is no reason for the cursor to be null, so you must check for valid column, table and database names.

Also after every change you make to any of these always uninstall the app from the emulator/device so the database is deleted and rerun the app to recreate everything.

Better way would be use Save data in a local database using Room

Here is your code I see null check is done but it protect only one statement from NPE. You need to wrap user creation under this if condition.

@Nullable

public User getUser(int id) {

    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.query(TABLE_NAME, // a. table

            COLUMNS, // b. column names

            " id = ?", // c. selections

            new String { String.valueOf(id) }, // d. selections args

            null, // e. group by

            null, // f. having

            null, // g. order by

            null); // h. limit



    if (cursor != null && cursor.moveToFirst()) {

       User user = new User();

       user.setId(Integer.parseInt(cursor.getString(0)));

       user.setWeight (Integer.parseInt(cursor.getString(1)));

       user.setAge(Integer.parseInt(cursor.getString(2)));



       return user;

   } 



   return null;

}