ViewPager setCurrentItem(pageId, true) does NOT smoothscroll

Question

I am compiling on SDK 4.03, Samsung Infuse Android 2.2, Support Library for Android 4, and using ViewPager in my app, actual swipe works fine, but when I do

Answer 1

I've fixed this by creating a MyViewPager that overrides the ViewPager.mScroller using reflection.

public class MyViewPager extends ViewPager {

    public MyViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        setMyScroller();
    }

    private void setMyScroller() {
        try {
            Class<?> viewpager = ViewPager.class;
            Field scroller = viewpager.getDeclaredField("mScroller");
            scroller.setAccessible(true);
            scroller.set(this, new MyScroller(getContext()));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public class MyScroller extends Scroller {
        public MyScroller(Context context) {
            super(context, new DecelerateInterpolator());
        }

        @Override
        public void startScroll(int startX, int startY, int dx, int dy, int duration) {
            super.startScroll(startX, startY, dx, dy, 1000 /*1 secs*/);
        }
    }
}

Answer 2

Note this variable mFirstLayout - it will be set true while viewpager callback onAttachedToWindow（such as on recyclerview），so will be not smoothScroll. You should override onAttachedToWindow to control the mFirstLayout variable. Something like this：

        @Override
        protected void onAttachedToWindow() {
            super.onAttachedToWindow();
            try {
                Field mFirstLayout = ViewPager.class.getDeclaredField("mFirstLayout");
                mFirstLayout.setAccessible(true);
                mFirstLayout.set(this, false);
                getAdapter().notifyDataSetChanged();
                setCurrentItem(getCurrentItem());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

Answer 3

I called setCurrentItem function in a handler and it worked fine for me.

new Handler().post(new Runnable() {
        @Override
        public void run() {
            myViewPager.setCurrentItem(1, true);
        }
    });

Hope this helps.

Answer 4

try with this code:

viewPager.postDelayed(new Runnable()
{
    @Override
    public void run()
    {
        viewPager.setCurrentItem(id, true);
    }
}, 100);

Answer 5

The ViewPager was changed a lot from revision 5 to 9. Some of those changes that might be related to your problem:

• Bug fixes for user interface behavior in ViewPager (revision 5 and 6)
• Fixed numerous bugs for ViewPager (revision 9)

Giving that your code is supposed to work just fine, my best guess is that your support library is not up-to-date. Try updating the library if it isn't.

Answer 6

After wasting my whole day I found a solution set offscreenPageLimit to total no. of the page.

please follow this https://stackoverflow.com/a/54800154/9097612