Android app crashes when retrieving data from SQLite database

Question

This is the retriver method:

public Cursor getData(String subj) {

    String selectQuery = "SELECT " + subj + " FROM " + TABLE_PRIMEIRO;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    if(cursor != null){
        cursor.moveToFirst();
    }
    return cursor;
}

This is how I'm displaying it in a TextView:

        Cursor cursor = db.getData("columnname");
        cursor.moveToFirst();
        String dataget = cursor.getString(cursor.getColumnIndex("columnname"));
        if (dataget!= null){
            textView1.setText(dataget);
        }

The app is made for API 23+, this code works fine on the API 23 emulator and on my own cellphone (which has Android 7.1) but it does not work on other cellphones. (Android 7.0 and 6.0).

Read https://stackoverflow.com/questions/23353173/unfortunately-myapp-has-stopped-how-can-i-solve-this for some tips to find the source of the error — Code-Apprentice, Feb 20 '18 at 18:51
It's a bit hard to find the problem when it actually works perfectly on the emulator and I can't get an error log... — JGG, Feb 20 '18 at 18:57
Did you create a 6.0 AVD? Or do you have a device that it crashes on? — Code-Apprentice, Feb 20 '18 at 19:14
I did create a 6.0 AVD, and no crash, but when I tried to run the app on my friend's 6.0 device it did crash. — JGG, Feb 20 '18 at 19:18

score 0 · Answer 1 · answered Feb 20 '18 at 19:28

Fixed it by changing:

    Cursor cursor = db.getData("columnname");
    cursor.moveToFirst();
    String dataget = cursor.getString(cursor.getColumnIndex("columnname"));
    if (dataget!= null){
        textView1.setText(dataget);
    }

To:

    Cursor cursor = db.getData("columnname");
    cursor.moveToFirst();
    if (cursor.moveToFirst()){
        String dataget = cursor.getString(cursor.getColumnIndex("columnname"));
        if (dataget!= null){
        textView1.setText(dataget);
        }
    }

Android app crashes when retrieving data from SQLite database

1 Answers1