Lifecycle

Lifecycle of components in Compose Multiplatform is adopted from the Jetpack Compose lifecycle concept. Lifecycle-aware components can react to changes in the lifecycle state of other components and help you produce better-organized, and often lighter, code that is easier to maintain.

Compose Multiplatform provides a common LifecycleOwner implementation, which extends the original Jetpack Compose functionality to other platforms and helps observe lifecycle states in common code.

States and events

The flow of lifecycle states and events (same as for the Jetpack lifecycle):

Lifecycle implementation

Composables usually don't need unique lifecycles: a common LifecycleOwner provides a lifecycle for all interconnected entities. By default, all composables created by Compose Multiplatform share the same lifecycle — they can subscribe to its events, refer to the lifecycle state, and so on.

When working with coroutines in multiplatform lifecycles, remember that the Lifecycle.coroutineScope value is tied to the Dispatchers.Main.immediate value, which might be unavailable on desktop targets by default. To make coroutines and flows in lifecycles work correctly with Compose Multiplatform, add the kotlinx-coroutines-swing dependency to your project. See Dispatchers.Main documentation for details.

Learn how the lifecycle works in navigation components in Navigation and routing.
Learn more about the multiplatform ViewModel implementation on the Common ViewModel page.

Mapping Android lifecycle to other platforms

iOS

Native events and notifications	Lifecycle event	Lifecycle state change
`viewDidDisappear`	`ON_STOP`	`STARTED` → `CREATED`
`viewWillAppear`	`ON_START`	`CREATED` → `STARTED`
`willResignActive`	`ON_PAUSE`	`RESUMED` → `STARTED`
`didBecomeActive`	`ON_RESUME`	`STARTED` → `RESUMED`
`didEnterBackground`	`ON_STOP`	`STARTED` → `CREATED`
`willEnterForeground`	`ON_START`	`CREATED` → `STARTED`
`viewControllerDidLeaveWindowHierarchy`	`ON_DESTROY`	`CREATED` → `DESTROYED`

Web

Due to limitations of the Wasm target, lifecycles:

Skip the CREATED state, as the application is always attached to the page.
Never reach the DESTROYED state, as web pages are usually terminated only when the user closes the tab.

Native event	Lifecycle event	Lifecycle state change
`blur`	`ON_PAUSE`	`RESUMED` → `STARTED`
`focus`	`ON_RESUME`	`STARTED` → `RESUMED`

Desktop

Swing listener callbacks	Lifecycle event	Lifecycle state change
`windowIconified`	`ON_STOP`	`STARTED` → `CREATED`
`windowDeiconified`	`ON_START`	`CREATED` → `STARTED`
`windowLostFocus`	`ON_PAUSE`	`RESUMED` → `STARTED`
`windowGainedFocus`	`ON_RESUME`	`STARTED` → `RESUMED`
`dispose`	`ON_DESTROY`	`CREATED` → `DESTROYED`

Last modified: 25 September 2024