Send ArrayList<Integer> between Bundle

Problem:
How do I transfer the data of _selectednumber and _points from onSaveInstanceState to onRestoreInstanceState?

private List<Integer> _selectednumber= new ArrayList<>();
private List<Integer> _points = new ArrayList<>();
private int _hit= 0;
private int _round = 1;


protected void onSaveInstanceState(Bundle out)
{
    super.onSaveInstanceState(out);

    out.putInt("p_hit", _hit);
    out.putInt("p_round", _round );
}


@Override
protected void onRestoreInstanceState(Bundle in)
{
    super.onRestoreInstanceState(in);

    _hit = in.getInt("p_hit");
    _round = in.getInt("p_round");
}

You can use putIntegerArrayList() to store the data, and getIntegerArrayList() to retrieve it. However, you've declared your variables as List<Integer>, which doesn't satisfy the requirements of putIntegerArrayList().

You have two choices. First, you can change how you've declared your variables so that they are explicitly ArrayLists, not just Lists:

private ArrayList<Integer> _selectednumber= new ArrayList<>();
private ArrayList<Integer> _points = new ArrayList<>();
private int _hit= 0;
private int _round = 1;

protected void onSaveInstanceState(Bundle out)
{
    super.onSaveInstanceState(out);

    out.putInt("p_hit", _hit);
    out.putInt("p_round", _round );
    out.putIntegerArrayList("p_selectednumber", _selectednumber);
    out.putIntegerArrayList("p_points", _points);
}

@Override
protected void onRestoreInstanceState(Bundle in)
{
    super.onRestoreInstanceState(in);

    _hit = in.getInt("p_hit");
    _round = in.getInt("p_round");
    _selectednumber = in.getIntegerArrayList("p_selectednumber");
    _points = in.getIntegerArrayList("p_points");
}

Or, you can wrap your List instances with new ArrayList<>() when you try to put them into the bundle:

private List<Integer> _selectednumber= new ArrayList<>();
private List<Integer> _points = new ArrayList<>();
private int _hit= 0;
private int _round = 1;

protected void onSaveInstanceState(Bundle out)
{
    super.onSaveInstanceState(out);

    out.putInt("p_hit", _hit);
    out.putInt("p_round", _round );
    out.putIntegerArrayList("p_selectednumber", new ArrayList<>(_selectednumber));
    out.putIntegerArrayList("p_points", new ArrayList<>(_points));
}

@Override
protected void onRestoreInstanceState(Bundle in)
{
    super.onRestoreInstanceState(in);

    _hit = in.getInt("p_hit");
    _round = in.getInt("p_round");
    _selectednumber = in.getIntegerArrayList("p_selectednumber");
    _points = in.getIntegerArrayList("p_points");
}