Detect if a ScrollView is scrolling up or down - Android

Question

I have one ScrollView with one LinearLayout with TextViews. I want to detect when ScrollView is scrolling up or down to hide/show ActionBar.

No direct way. Maybe this will help you. [http://stackoverflow.com/questions/3948934/synchronise-scrollview-scroll-positions-android][1] [1]: http://stackoverflow.com/questions/3948934/synchronise-scrollview-scroll-positions-android — Nazgul, Dec 04 '14 at 15:20

score 5 · Accepted Answer · answered Dec 04 '14 at 15:22

5

you need to create a class that extends ScrollView

public class ExampleScrollView extends ScrollView

and then Override onScrollChanged that gives you the old and new scroll positions and from there you can detect which direction

protected void onScrollChanged(int l, int t, int oldl, int oldt)

answered Dec 04 '14 at 15:22

tyczj

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Than I need to add my new ExampleScrollView in xml file. Right? – KiKo Dec 04 '14 at 15:28
yes with the full class path ie. `com.my.app.ExampleScrollView` – tyczj Dec 04 '14 at 15:29
I get errors: Custom view ExampleScrollView is not using the 2- or 3-argument View constructors; XML attributes will not work – KiKo Dec 04 '14 at 15:44
well yeah you have to implement all the proper constructors – tyczj Dec 04 '14 at 15:49

Criss · Answer 2 · 2017-07-12T18:58:33.167

check this out

scrollView.setOnTouchListener(new View.OnTouchListener() {
  float y0 = 0;
  float y1 = 0;

  @Override
  public boolean onTouch(View view, MotionEvent motionEvent) {

    if (motionEvent.getAction() == MotionEvent.ACTION_MOVE) {
      y0 = motionEvent.getY();
      if (y1 - y0 > 0) {
        Log.i("Y", "+");
        AnimateFloat(true);
      } else if (y1 - y0 < 0) {
        Log.d("Y", "-");
        AnimateFloat(false);
      }
      y1 = motionEvent.getY();
    }

    return false;
  }
});

score 4 · Answer 3 · answered Jan 29 '20 at 21:26

I think I am little bit late to answer this but here is my answer

 scrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
            float y = 0;

            @Override
            public void onScrollChanged() {
                if (scrollView.getScrollY() > y) {
                    Log.v("Message", "Scrolls Down");
                } else {
                    Log.v("Message", "Scrolls Up");
                }
                y = scrollView.getScrollY();
            }
        });

score 0 · Answer 4 · answered Dec 04 '17 at 12:31

A sure short answer

scroll.setOnScrollChangeListener(new View.OnScrollChangeListener() {
    @Override
    public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {


                int x = scrollY - oldScrollY;
                if (x > 0) {
                    //scroll up
                } else if (x < 0) {
                    //scroll down
                } else {

                }

    }
});

Detect if a ScrollView is scrolling up or down - Android

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