Detect scroll view reaching its top - Android

Question

I have used scrollview in my Android app using activity_main.xml. The scroll is working perfectly. But the thing is i need to add a Scroll to top button so that if the user starts scrolling the button should be visible like the link below..

http://webdesignerwall.com/demo/scroll-to-top/scrolltotop.html?

I need to do this in Android..

Are you using the listview or gridview in yours scrollView?? — Ravindra Kushwaha, May 18 '15 at 05:46
thank you @kgandroid.. but i need to view the button only when the page scrolls.. — Jessie Ka, May 18 '15 at 05:57
You can use something like this, http://stackoverflow.com/questions/10713312/can-i-have-onscrolllistener-for-a-scrollview/23365539#23365539. — Hasmukh Barochiya, May 18 '15 at 05:58
You have to play with Visibility and Invisibility of button when the user scroll down the view...On click on that button use these View.setVerticalScrollBarEnabled(true); Here View is the top View of the scrollView — Ravindra Kushwaha, May 18 '15 at 05:59
try: http://stackoverflow.com/questions/8181828/android-detect-when-scrollview-stops-scrolling — kgandroid, May 18 '15 at 06:01
ya i m doing the same.. My confusion is how to detect when the user reaches top of the screen so that i can make it invisible.. — Jessie Ka, May 18 '15 at 06:02

score 10 · Answer 1 · answered Feb 03 '16 at 11:35

Use the below code to detect the top of the scroll.

final ViewTreeObserver.OnScrollChangedListener onScrollChangedListener = new
            ViewTreeObserver.OnScrollChangedListener() {

                @Override
                public void onScrollChanged() {
                    if (scrollview.getScrollY() == 0) {
                        swipeRefreshLayout.setEnabled(true);
                    } else
                        swipeRefreshLayout.setEnabled(false);
                }
            };
    scrollview.setOnTouchListener(new View.OnTouchListener() {
        private ViewTreeObserver observer;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (observer == null) {
                observer = scrollview.getViewTreeObserver();
                observer.addOnScrollChangedListener(onScrollChangedListener);
            } else if (!observer.isAlive()) {
                observer.removeOnScrollChangedListener(onScrollChangedListener);
                observer = scrollview.getViewTreeObserver();
                observer.addOnScrollChangedListener(onScrollChangedListener);
            }
            return false;
        }
    });

I think you should return true in onTouch method. by the way thanks. — Reza, Nov 22 '20 at 13:00

score 8 · Answer 2 · answered Sep 28 '17 at 10:17

 scrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
            @Override
            public void onScrollChanged() {
                if (scrollView != null) {
                    if (scrollView.getScrollY()==0) {
                        Toast.makeText(getContext(),"top",Toast.LENGTH_SHORT).show();
                    } else {

                    }
                }
            }
        });

Detect scroll view reaching its top - Android

2 Answers2