Android CollapsingToolbarLayout collapse Listener

I share the full implementation, based on @Frodio Beggins and @Nifhel code:

public abstract class AppBarStateChangeListener implements AppBarLayout.OnOffsetChangedListener {    public enum State {        EXPANDED,        COLLAPSED,        IDLE    }    private State mCurrentState = State.IDLE;    @Override    public final void onOffsetChanged(AppBarLayout appBarLayout, int i) {        if (i == 0) {            if (mCurrentState != State.EXPANDED) {                onStateChanged(appBarLayout, State.EXPANDED);            }            mCurrentState = State.EXPANDED;        } else if (Math.abs(i) >= appBarLayout.getTotalScrollRange()) {            if (mCurrentState != State.COLLAPSED) {                onStateChanged(appBarLayout, State.COLLAPSED);            }            mCurrentState = State.COLLAPSED;        } else {            if (mCurrentState != State.IDLE) {                onStateChanged(appBarLayout, State.IDLE);            }            mCurrentState = State.IDLE;        }    }    public abstract void onStateChanged(AppBarLayout appBarLayout, State state);}

And then you can use it:

appBarLayout.addOnOffsetChangedListener(new AppBarStateChangeListener() {    @Override    public void onStateChanged(AppBarLayout appBarLayout, State state) {        Log.d("STATE", state.name());    }});

This solution works perfectly for me to detect AppBarLayout collapsed or expanded.

appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {        @Override        public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {            if (Math.abs(verticalOffset)-appBarLayout.getTotalScrollRange() == 0)            {                //  Collapsed            }            else            {                //Expanded            }        }    });

Used addOnOffsetChangedListener on the AppBarLayout.

Hook a OnOffsetChangedListener to your AppBarLayout. When the verticalOffset reaches 0 or less than the Toolbar height, it means that CollapsingToolbarLayout has collapsed, otherwise it is expanding or expanded.

mAppBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {            @Override            public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {                if(verticalOffset == 0 || verticalOffset <= mToolbar.getHeight() && !mToolbar.getTitle().equals(mCollapsedTitle)){                    mCollapsingToolbar.setTitle(mCollapsedTitle);                }else if(!mToolbar.getTitle().equals(mExpandedTitle)){                    mCollapsingToolbar.setTitle(mExpandedTitle);                }            }        });