android - Show CollapsingToolbarLayout title only when collapsed

Question

I've tried setExpandedTitleColor and setCollapsedTitleColor (switching to and from transparent) with no luck. I can't see any built in methods that'll do what I'm looking for, either.

I only want to show the title when the CollapsingToolbarLayout is fully collapsed, otherwise, I need it hidden.

Any hints?

Answer 1

You can add OnOffsetChangedListener to AppBarLayout to determine when CollapsingToolbarLayout is collapsed or expanded and set it's title.

Java

final CollapsingToolbarLayout collapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.collapsingToolbarLayout);
AppBarLayout appBarLayout = (AppBarLayout) findViewById(R.id.appBarLayout);
appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
    boolean isShow = true;
    int scrollRange = -1;

    @Override
    public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
        if (scrollRange == -1) {
            scrollRange = appBarLayout.getTotalScrollRange();
        }
        if (scrollRange + verticalOffset == 0) {
            collapsingToolbarLayout.setTitle("Title");
            isShow = true;
        } else if(isShow) {
            collapsingToolbarLayout.setTitle(" ");//careful there should a space between double quote otherwise it wont work 
            isShow = false;
        }
    }
});

---

Kotlin

var isShow = true
var scrollRange = -1
appBarLayout.addOnOffsetChangedListener(AppBarLayout.OnOffsetChangedListener { barLayout, verticalOffset ->
    if (scrollRange == -1){
        scrollRange = barLayout?.totalScrollRange!!
    }
    if (scrollRange + verticalOffset == 0){
        collapsingToolbarLayout.title = "Title Collapse"
        isShow = true
    } else if (isShow){
        collapsingToolbarLayout.title = " " //careful there should a space between double quote otherwise it wont work
        isShow = false
    }
})