CollpaseActivity.kt

...
    collapsing_toolbar_layout.title = "Ronaldo Fenômeno"
    collapsing_toolbar_layout.setExpandedTitleColor(resources.getColor(android.R.color.transparent))

    //Listener para escutar mudanças de estado da AppBarLayout
    app_bar.addOnOffsetChangedListener(object : AppBarLayout.OnOffsetChangedListener{
        override fun onOffsetChanged(appBarLayout: AppBarLayout?, verticalOffset: Int) {

            if (verticalOffset == 0)
                tv_title_article.visibility = View.VISIBLE
            else
                tv_title_article.visibility = View.INVISIBLE
        }

    })
...