Android ViewPager "slide lag"

Question

I have a ViewPager Fragment with 3 fragments. Each of it has an image as background and a TextView. The TextView is always absolute on the left side of the screen (not the Fragment itself). When I move the fragments with my finger, it stays at the correct position. Also when I move it fast. But when I let it slide into the other Fragment, the TextView doesn't stays at the correct position. It looks like it lags around.

It should stay like in these 2 pictures:

 @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        SingleTabFragment singleTabFragment = (SingleTabFragment) mSectionsPagerAdapter.getRegisteredFragment(position);
        TextView textView = singleTabFragment.getNonResizingTextView();
        ViewGroup.MarginLayoutParams marginLayoutParams = (ViewGroup.MarginLayoutParams)textView.getLayoutParams();
        marginLayoutParams.leftMargin = positionOffsetPixels;
        textView.setLayoutParams(marginLayoutParams);

    }

I really don't know what the problem is. I tried it multiple ways, i added Thread.sleep(50); to see if it also happens there. And yes, also there it doesn't work correct. How can I fix this?

EDIT:

Now I have put in the middle. But the problem is the same.

Here is how it should look like (I know, not that much frames. But I think you will get the point):

And if I let it slide it looks like this:

Can you post a gif with that behavior? – azizbekian Aug 24 '17 at 07:07 — azizbekian, Aug 24 '17 at 07:07
@azizbekian yes, I've edited it. – user6586661 Aug 24 '17 at 08:35 — user6586661, Aug 24 '17 at 08:35

score 1 · Answer 1 · answered Aug 29 '17 at 11:29

You can use following method to do the same instead of doing it in onPageScrolled:

mPager.setPageTransformer(false, new FadePageTransformer());

public class FadePageTransformer implements ViewPager.PageTransformer {
        public void transformPage(View view, float position) {
            view.setAlpha(1 - Math.abs(position));
                    if (position < 0) {
                        view.setScrollX(-(int) ((float) (view.getWidth()) * -position));
                    } else if (position > 0) {
                        view.setScrollX((int) ((float) (view.getWidth()) * position));
                    } else {
                        view.setScrollX(0);
                    }
        }
    }

score 1 · Answer 2 · answered Aug 29 '17 at 12:35

1

use textView.setTranslationX(positionOffsetPixels); instead of margins

answered Aug 29 '17 at 12:35

Antonis Lat

545
4
9

score 1 · Accepted Answer · answered Aug 30 '17 at 17:58

 TextView textView = singleTabFragment.getNonResizingTextView();
 textView.translationX = positionOffsetPixels;

You should not do marginLayoutParams.leftMargin = positionOffsetPixels; because changing the margin may change the position of the View, which will cause the View to be re-layout on every frame. That is why it is lagging. Changing the translationX will only change how the view is drawn instead of it's position.

score -1 · Answer 4 · answered Aug 30 '17 at 14:43

-1

Have a look at Slowing speed of Viewpager controller in android

You can set custom duration for Viewpager scrolling.

answered Aug 30 '17 at 14:43

Vamsi

878
1
8
25

Android ViewPager "slide lag"

4 Answers4