adapter

public class TabAdapter extends FragmentStatePagerAdapter {

    private int numberOfTabs;

    public TabAdapter(FragmentManager fm, int numberOfTabs) {
        super(fm);
        this.numberOfTabs = numberOfTabs;
    }

    @Override
    public Fragment getItem(int i) {

        switch (i) {
            case 0:
                return new YesterdayFragment();
            case 1:
                return new TodayFragment();
            case 2:
                return new TomorrowFragment();
            default:
                return null;
        }
    }

    @Override
    public int getCount() {
        return numberOfTabs;
    }
}