public class MainActivity extends FragmentActivity {

private ViewPager pager;
private RadioGroup radiogroup;
private Dao dao;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    dao = new Dao(this);
    pager = (ViewPager) findViewById(R.id.pager);
    final List<Fragment> list=new ArrayList<Fragment>();
    Frag1 frag1=new Frag1();
    Frag2 frag2=new Frag2();
    Frag3 frag3=new Frag3();
    list.add(frag1);
    list.add(frag2);
    list.add(frag3);
    radiogroup = (RadioGroup)findViewById(R.id.radiogroup);
    radiogroup.check(radiogroup.getChildAt(0).getId());
    pager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
        @Override
        public Fragment getItem(int i) {
            return list.get(i);
        }

        @Override
        public int getCount() {
            return list.size();
        }

    });
    pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int i, float v, int i1) {

        }

        @Override
        public void onPageSelected(int i) {

            radiogroup.check(radiogroup.getChildAt(i).getId());
        }

        @Override
        public void onPageScrollStateChanged(int i) {

        }
    });
    radiogroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            switch (checkedId){
                case R.id.radio1:
                    pager.setCurrentItem(0);
                    break;
                case R.id.radio2:
                    pager.setCurrentItem(1);
                    break;
                case R.id.radio3:
                    pager.setCurrentItem(2);
                    break;
            }
        }
    });
}

public Dao getDao() {
    return dao;
}

}