发送网络请求，因为FragmentPagerAdapter显示了Fragment

Question

I am using the FragmentPagerAdapter which shows three fragments by using ViewPager. I have setOffscreenPageLimit to 3 so all the three fragments send the network request simultaneously as they are visible(I have send the network request on Fragment.onActivityCreated()). But I want network request is send only when Fragment is visible(means user is scrolled to that fragment).

Note: I am using the setOffscreenPageLimit to 3 because every time the fragment is created no new network request is created and show the catches fragment

Answer 1

Making network requests in oncreateview () of every fragment should do what you want to. example :Something that ive been using . Parent activity with fragment pager adapter.

public class HomeActivity extends SherlockFragmentActivity{

      private static final String[] CONTENT = new String[] { "Fragment 1", "Fragment 2" };

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.homexml);
Bundle extra = getIntent().getExtras();
int i = Integer.parseInt(extra.getString("id")); 
        FragmentPagerAdapter adapter = new FragmentAdapter(getSupportFragmentManager());

            ViewPager pager = (ViewPager)findViewById(R.id.pager);
            pager.setAdapter(adapter);

            TitlePageIndicator indicator = (TitlePageIndicator) findViewById(R.id.indicator);
            indicator.setViewPager(pager);
         switch (i)
         {

         case 2:
             pager.setCurrentItem(0);
        break;
         case 3:
             pager.setCurrentItem(1);
//      break;
//       case 4:
//           pager.setCurrentItem(3);
//      break;
//       case 5:
//           pager.setCurrentItem(4);
//      break;
//       case 6:
//           pager.setCurrentItem(5);
//      break;
//       case 7:
//           pager.setCurrentItem(6);
//      break;
//           default:
//               pager.setCurrentItem(0);
//               break;
         }

           indicator.setFooterIndicatorStyle(IndicatorStyle.Underline);
           indicator.setFooterColor(Color.parseColor("#e7c450"));


        }


      class FragmentAdapter extends FragmentPagerAdapter {
          SherlockFragment frg; 
          public FragmentAdapter(FragmentManager fm) {
                super(fm);
            }

            @Override
            public SherlockFragment getItem(int position) {
                switch (position)
                {
                case 0:
           frg = new fragment1();
                break;
                case 1:
           frg = new fragment2();
                    break; 
                    }
            return frg; 
            }

            @Override
            public CharSequence getPageTitle(int position) {
                return CONTENT[position];
            }

//          @Override public int getIconResId(int index) {
//            return ICONS[index];
//          }

          @Override
            public int getCount() {
              return CONTENT.length;
            }
        }

Pass specify the fragments in the adapter. make network requests in onCreateView() of every fragment. that way network requests will be only made when fragment is visible.