Viewpager + Adapter In Fragment => Laggy Swiping

I have a ViewPager with some fragments. Each fragment has a ListView in a SlidingDrawer (=invisible before swiping) with an ArrayAdapter. Adapter is set on onCreateView(), that sl

Solution 1:

I had a similar problem... I used listeners. Still, when you swipe two pages back to back it was laggy... I did something like this that improved the experience....

viewpager.setOnPageChangeListener(newOnPageChangeListener() {
    int positionCurrent;
    boolean dontLoadList;
    @OverridepublicvoidonPageScrollStateChanged(int state) {   
        if(state == 0){ // the viewpager is idle as swipping endednewHandler().postDelayed(newRunnable() {
                    publicvoidrun() {
                        if(!dontLoadList){
                        //async thread code to execute loading the list... 
                        }
                    }
                },200);
            }
        }
    }

    @OverridepublicvoidonPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        positionCurrent = position; 
        if( positionOffset == 0 && positionOffsetPixels == 0 ) // the offset is zero when the swiping ends{
            dontLoadList = false;
        }
        elsedontLoadList=true; // To avoid loading content for list after swiping the pager.
    }

}

If you take a few milli seconds to load the list that comes as supplement to the viewpager, its ok in terms of UX rather than giving a bad swiping experience... So, the idea is to wait for 400ms in the thread before loading the list and making sure that you actually dont load content when the user is trying to swipe fast to see the viewpager content...

Solution 2:

My Question is, wether it is possible to set the Adapter after swiping when it Pager is idle?

There is the OnPageChangeListener that you could set on the ViewPager to monitor the swipe gestures. You could then use the onPageSelected()(or the onPageScrollStateChanged() to monitor the current state) method to get notified when a new page has been selected and start from that method the loading of data.

Also, make sure the ListView are responsible for the lag and not some other part of your code.