防止FragmentPagerAdapter对所有Fragment的onResume操作

有的时候，我们不希望FragmentPagerAdapter对所有Fragment做onResume操作。我的Fragment可能有网络请求，这时候如果都做了onResume，对网络资源是一种浪费。我们希望，只有在Fragment是可见的情况下，onResume才是有效的。可以这么做：

public abstract class BaseFragment extends Fragment {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
              ...
    }


    ...
    ...


    @Override
    public void onResume()
    {
        super.onResume();
        if (!getUserVisibleHint())
        {
            return;
        }
        onRefresh();
    }

    @Override
    public void setUserVisibleHint(boolean visible)
    {
        super.setUserVisibleHint(visible);
        if (visible && isResumed())
        {
            //Only manually call onResume if fragment is already visible
            //Otherwise allow natural fragment lifecycle to call onResume
            onResume();
        }
    }
}