Links

Stack API

SnapshotStateStack

Voyager is backed by a SnapshotStateStack:
You will use it to navigate forward (push, replace, replaceAll) and backwards (pop, popAll, popUntil), but the SnapshotStateStack can also be used as a regular collection outside the Navigator.
val stack = mutableStateStackOf("🍇", "🍉", "🍌", "🍐", "🥝", "🍋")
// 🍇, 🍉, 🍌, 🍐, 🥝, 🍋
stack.lastItemOrNull
// 🍋
stack.push("🍍")
// 🍇, 🍉, 🍌, 🍐, 🥝, 🍋, 🍍
stack.pop()
// 🍇, 🍉, 🍌, 🍐, 🥝, 🍋
stack.popUntil { it == "🍐" }
// 🍇, 🍉, 🍌, 🍐
stack.replace("🍓")
// 🍇, 🍉, 🍌, 🍓
stack.replaceAll("🍒")
// 🍒
You can also create a SnapshotStateStack through rememberStateStack(), it will restore the values after Activity recreation.

Events

Whenever the content changes, the SnapshotStateStack will emit a StackEvent. Use the stack.lastEvent to get the most recent one.
The available events are:
  • Push: whenever push is called
  • Replace: whenever replace and replaceAll are called
  • Pop: whenever pop and popAll are called
  • Idle: default event
This is very useful for deciding which transition to make.

Sample

Source code here.