How can I determine that CollapsingToolbar is collapsed?

Question

I need to know when CollapsingToolbar from material design library is collapsed.

score 101 · Answer 1 · answered Sep 10 '16 at 08:47

101

As Marko said, this can be achieved using your own implementation of a OnOffsetChangedListener.

AppBarLayout appBarLayout = (AppBarLayout) view.findViewById(R.id.app_bar_layout);
appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
        @Override
        public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
            if (Math.abs(verticalOffset) == appBarLayout.getTotalScrollRange()) {
                // Collapsed
            } else if (verticalOffset == 0) {
                // Expanded
            } else {
                // Somewhere in between
            }
        }
    }););

answered Sep 10 '16 at 08:47

chrlaura

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1
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11

This solution seems to be the most popular one. However, in my case, the problem is that the `addOnOffsetChangedListener` are called every time while collapsing/expanding unless you stop moving your finger. Is it possible to detect the state only than when it is either expanded or closed and only after one of those state execute some code? – Mark Delphi Oct 09 '20 at 15:18
This solution works like a charm.. Just one thing - that since I had disabled collapsable toolbar's scroll flags in certain conditions so getTotalScrollRange() for me was 0 and hence it was always showing me "collapsed" state. Interchanging the 'if" and "else if" serves best in that case. – Damanpreet Singh Nov 23 '20 at 13:23

score 81 · Accepted Answer · edited Nov 21 '17 at 19:11

81

UPDATE: Since support versions of 23.1.1+ the issue is no longer there, no need to use the listener and disable the swipe refresh layout, it will work as it should (link).

Implement AppBarLayout.OnOffsetChangedListener listener on your AppBarLayout

AppBarLayout appBarLayout = (AppBarLayout) view.findViewById(R.id.app_bar_layout);
appBarLayout.addOnOffsetChangedListener(this);

And check if offset is 0, meaning the toolbar is fully expanded.

@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int offset)
{
    if (offset == 0)
    {
        // Fully expanded
    }
    else
    {
        // Not fully expanded or collapsed
    }
}

edited Nov 21 '17 at 19:11

Ognian Gloushkov

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answered Aug 07 '15 at 08:21

Marko

20,385
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1

@Atieh to further explain it, when the collapsing toolbar is fully expanded the offset value is equal to zero (offset == 0) – ponnex Feb 20 '16 at 17:00
1

I changed the if condition to `verticalOffset < -710` then the problem solved. not elegant but it works – Logan Guo Apr 20 '16 at 15:36
To detect if fully collapsed check if Math.abs(offset) == appBarLayout – user1840378 Dec 13 '16 at 22:10
As @Atieh said this is NOT the right answer, Upvotes are missleading, Maybe users should try it first then upvote ! – Farshad Aug 22 '17 at 06:20
I will re-test this and correct it if there is a mistake. – Marko Aug 22 '17 at 08:27
And how would it be when Scrool returns but only the Toolbar is visible and fixed at the top?Like this:https://stackoverflow.com/questions/46981038/transparent-statusbar-when-collapsed/46986273 @Marko – TiagoIB Oct 28 '17 at 13:11

Eduard B. · Answer 3 · 2015-08-07T11:40:27.610

Take a look over this github gist

public class MyAppBarLayout extends AppBarLayout
        implements AppBarLayout.OnOffsetChangedListener {

    private State state;
    private OnStateChangeListener onStateChangeListener;

    public MyAppBarLayout(Context context) {
        super(context);
    }

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

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        if (!(getLayoutParams() instanceof CoordinatorLayout.LayoutParams)
                || !(getParent() instanceof CoordinatorLayout)) {
            throw new IllegalStateException(
                    "MyAppBarLayout must be a direct child of CoordinatorLayout.");
        }
        addOnOffsetChangedListener(this);
    }

    @Override
    public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
        if (verticalOffset == 0) {
            if (onStateChangeListener != null && state != State.EXPANDED) {
                onStateChangeListener.onStateChange(State.EXPANDED);
            }
            state = State.EXPANDED;
        } else if (Math.abs(verticalOffset) >= appBarLayout.getTotalScrollRange()) {
            if (onStateChangeListener != null && state != State.COLLAPSED) {
                onStateChangeListener.onStateChange(State.COLLAPSED);
            }
            state = State.COLLAPSED;
        } else {
            if (onStateChangeListener != null && state != State.IDLE) {
                onStateChangeListener.onStateChange(State.IDLE);
            }
            state = State.IDLE;
        }
    }

    public void setOnStateChangeListener(OnStateChangeListener listener) {
        this.onStateChangeListener = listener;
    }

    public interface OnStateChangeListener {
        void onStateChange(State toolbarChange);
    }

    public enum State {
        COLLAPSED,
        EXPANDED,
        IDLE
    }
}

This works elegantly @EdyBolos thanks a ton for sharing. Flawless! — Suleiman19, Sep 24 '15 at 14:05

score 2 · Answer 4 · answered Mar 18 '19 at 02:42

 appBarLayout.addOnOffsetChangedListener(AppBarLayout.OnOffsetChangedListener { appBarLayout, verticalOffset ->

        if (Math.abs(verticalOffset)  >= appBarLayout.totalScrollRange) { // collapse
        } else if (verticalOffset == 0) { // fully expand

        } else { // scolling

        }
    })

appBarLayout.totalScrollRange is not always equal to verticalOffset in some case, better check verticalOffset larger than totoalScrollRange

score 0 · Answer 5 · answered Oct 19 '18 at 11:38

appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() 
{
        @Override
        public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset)
 {

            if (Math.abs(verticalOffset)-appBarLayout.getTotalScrollRange() == 0)
            {
                //  on Collapse
            }
            else
            {
               //  on expand
            }
        }
    });

How can I determine that CollapsingToolbar is collapsed?

5 Answers5

Linked