Mixing of items with different width within one and the same Horizontal List is thus not possible. The consequence of the mentioned optimizations is that the view expects all items to have equal width. The view is also optimized regarding the speed permitting even very long lists being scrolled smoothly. Later when the user scrolls the list, the view takes care of the old items being replaced with new contents so that the user has the impression of a continuous list. For this purpose, the view retains only few of the items in the memory. The Horizontal List view is optimized to efficiently manage with very long lists consisting of thousands of items. The list can, for example, display picture thumbnails stored in the device:

This so-called Horizontal List can be used to compose the appearance of a GUI component, in particular to present lists with options, menu items or data records the user can inspect, scroll and select.

The Mosaic class Core::HorizontalList implements a special kind of view intended to display items arranged horizontally side by side. Managing scrollable contents: Horizontal List

Android studio listview horizontal