Android - Sharedpreferences Collect Data

Question

I generate a random number when I open the application and I save this number with Sharedpreferences. This is my code:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Random r = new Random();
        int number = r.nextInt(100);

        SharedPreferences randomnumber = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = randomnumber.edit();
        editor.putInt("intValue",number);
        editor.commit();
    }
}

Can I collect old and new numbers when I open the application?

I want to collect old and new data in each record @Pavneet_Singh — Johny, Aug 01 '17 at 15:11
I think you would be better of using an SQLite table as you can add new numbers rather than overwriting existing values - https://developer.android.com/training/basics/data-storage/databases.html — RobVoisey, Aug 01 '17 at 15:29

score 2 · Answer 1 · answered Aug 01 '17 at 15:10

You are overriding the old value with the new value with this

editor.putInt("intValue",number);

That's why you will always see one value for it. You could either have different field names or use an array for example like this How can I store an integer array in SharedPreferences?

score 1 · Answer 2 · answered Aug 01 '17 at 15:10

Get old value before it set new value..

    Random r = new Random();
    int number = r.nextInt(100);

    SharedPreferences randomnumber = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());

    String old = randomnumber.getString('intValue');  // old value

    SharedPreferences.Editor editor = randomnumber.edit();
    editor.putInt("intValue",number); // set new value
    editor.apply();

Android - Sharedpreferences Collect Data

2 Answers2