Scrollable Column

Lazy Column

LazyColumn/Row is the RecyclerView of Compose.

If you have a large number of items to display, using a LazyColumn/Row instead of a scrollable Column/Row can improve performance. This is because the non-lazy Column/Row will measure and layout all child @Composables even if they exceed visible bounds.

Item Keys

If the data in the list can change (eg: add/remove item, drag & drop item), a key must be provided so that LazyColumn/Row can know where items move to.

This enables LazyColumn/Row to remember item scroll position and perform item animations.

In this example, although every item looks the same, its key is unique.

Content Type

If the data can be logically grouped into different categories, providing contentType can further improve performance.

This is a similar concept to RecyclerView's Item View Type, but it is not required. The example code will work even if you don't provide contentType.