android.support.v4.view.ViewPager#startAnimation ( )源码实例Demo

private void setupViewPager(final ViewPager viewPager) {
    ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new TabFragment(), "OVERVIEW");
    adapter.addFragment(new TabFragment(), "USAGE");
    adapter.addFragment(new TabFragment(), "STYLE");
    viewPager.setAdapter(adapter);

    Animation bottomUp = AnimationUtils.loadAnimation(DetailActivity.this,
            R.anim.bottom_up);
    viewPager.startAnimation(bottomUp);


}
 

@Override
protected
void onPostExecute(TreeMap<Long, FeedItem>[] result)
{
    ViewPager pager = (ViewPager) m_activity.findViewById(R.id.viewpager);
    PagerAdapter pagerAdapter = pager.getAdapter();
    int pageCount = pagerAdapter.getCount();

    for(int i = 0; pageCount > i; i++)
    {
        // Get the tag page and skip ListViews that are null.
        ListFragmentTag fragment = FragmentFeeds.getViewPagerFragment(i);
        LinkedMapAdapter<Long, FeedItem> adapterTag = fragment.getListAdapter();
        ListViewFeeds listView = fragment.getListView();

        if(null == adapterTag)
        {
            fragment.setListAdapter(new AdapterFeedItems(m_activity, result[i]));
            listView.setSelectionOldestUnread(m_activity.getReadItemTimes());
        }
        else
        {
            long topKeyBefore = 0L;
            int top = 0;

            // If there are items in the currently viewed page, save the position.
            boolean firstLoad = null == listView || 0 == listView.getCount();
            if(!firstLoad)
            {
                // Get the time of the top item.
                int topVisibleItem = listView.getFirstVisiblePosition();
                topKeyBefore = adapterTag.getKey(topVisibleItem);

                View v = listView.getChildAt(0);
                top = null == v ? 0 : v.getTop();
            }

            // Update the feedItems in the adapter.
            adapterTag.replaceAll(result[i]);

            // Now find the position of the item with the time timeBefore.
            if(firstLoad)
            {
                listView.setSelectionOldestUnread(m_activity.getReadItemTimes());
            }
            else
            {
                int newPos = adapterTag.indexOf(topKeyBefore);
                listView.setSelectionFromTop(newPos, top - listView.getPaddingTop());
            }
        }
    }

    // If the pager is invisible, use a fade in animation.
    if(View.VISIBLE != pager.getVisibility())
    {
        pager.setVisibility(View.VISIBLE);
        AlphaAnimation animation = new AlphaAnimation(0.0F, 1.0F);
        animation.setDuration(300);
        pager.startAnimation(animation);
    }
}