Why do we need AppBarLayout when we are using CollapsingToolbarLayout?

Question

Also, what's the difference between an appbar layout and a collapsing toolbar layout?

Thanks a lot :)

Answer 1

AppBarLayout is a vertical LinearLayout which implements many of the features of material designs app bar concept, namely scrolling gestures.

Children should provide their desired scrolling behavior through setScrollFlags(int) and the associated layout xml attribute: app:layout_scrollFlags.

This view depends heavily on being used as a direct child within a CoordinatorLayout. If you use AppBarLayout within a different ViewGroup, most of it's functionality will not work.

CollapsingToolbarLayout is a wrapper for Toolbar which implements a collapsing app bar. It is designed to be used as a direct child of a AppBarLayout.