How to animate scroll position? How to scroll smoothly?

Question

I wish to move smoothly to next scroll position in my custom view (on button press or event). How to implement this? First of all I can't see scroll animation class (only alpha, rotate, scale and translate). Secondly, having animation class, I can't see iterative one (say to scroll 100 pixels rights whatever position we have) only absolute ones (i.e. to animate from one constant value to another).

score 46 · Answer 1 · answered May 16 '12 at 15:14

46

Assuming you are using a ScrollView, does smoothScrollTo(...) work for you?

http://developer.android.com/reference/android/widget/ScrollView.html#smoothScrollTo%28int,%20int%29

answered May 16 '12 at 15:14

Ian Warwick

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Should I use `ScrollView`? I am using `MyClass extends View` now. – Suzan Cioc May 16 '12 at 15:18
I think it depends on what you are doing, if a ScrollView works for you then definetly use it. – Ian Warwick May 16 '12 at 15:26
I have tried extending `ScrollView` but found that `onScrollChanged()` doesn't called in the case. I need this method to be called since I calculate some parameters in it. I.e. `smoothScroll` doesn't work for me. – Suzan Cioc May 16 '12 at 16:38
I assume you have subclassed ScrollView and overriden onScrollChanged? – Ian Warwick May 17 '12 at 07:06
This also works in a `RecyclerView`, with `smoothScrollToPosition()`. – Ben Grant Jan 11 '18 at 02:54
Smooth scroll isn't so smooth. I am using @anton46's answer as that allows you to specify the duration of the scrool: https://stackoverflow.com/a/21574048/1617737 – ban-geoengineering Mar 08 '19 at 19:05

score 39 · Answer 2 · edited Jun 21 '19 at 02:14

Using ObjectAnimator, this is a sample for scrolling to top:

public void scrollToTop() {
    int x = 0;
    int y = 0;

    ObjectAnimator xTranslate = ObjectAnimator.ofInt(mScrollView, "scrollX", x);
    ObjectAnimator yTranslate = ObjectAnimator.ofInt(mScrollView, "scrollY", y);

    AnimatorSet animators = new AnimatorSet();
    animators.setDuration(1000L);
    animators.playTogether(xTranslate, yTranslate);

    animators.addListener(new AnimatorListener() {

        @Override
        public void onAnimationStart(Animator arg0) {
            // TODO Auto-generated method stub
        }

        @Override
        public void onAnimationRepeat(Animator arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onAnimationEnd(Animator arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onAnimationCancel(Animator arg0) {
            // TODO Auto-generated method stub

        }
    });
    animators.start();
}

score 1 · Answer 3 · answered Jul 08 '13 at 02:21

1

Animating scroll is done through a combination of using Scroller/OverScroller (to compute the time interpolated values of your scroll offsets), GestureDetectors (to start the scroller object) and the onComputeScroll method of a View (which implicitly is your animation loop).

The official android docs now have a detailed tutorial on precisely this topic. http://developer.android.com/training/gestures/scroll.html

answered Jul 08 '13 at 02:21

numan salati

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1

that is explaining how to implement a ScrollView from scratch! that's not the answer – Shayan_Aryan Jun 23 '21 at 14:57

score 0 · Answer 4 · answered May 17 '12 at 11:37

0

See the view_cache_demo sample code to see how to do animated scrolling. It works in 2D, caches complex drawing and also handles fling gestures, but you can simplify all that as necessary.

answered May 17 '12 at 11:37

Lawrence D'Oliveiro

2,768
1
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How to animate scroll position? How to scroll smoothly?

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