App Lifecycle¶

The App object provides metadata about the running app and its lifecycle state. Always available — no permissions required.

Properties¶

Property	Type	Description
`appId`	`string`	The app's reverse-domain identifier (constant)
`appVersion`	`string`	The app's version from `manifest.json` (constant)
`hostVersion`	`string`	The Squared host app version (constant)
`lifecycle`	`Lifecycle`	Current lifecycle state

Lifecycle States¶

State	Description
`App.Active`	App is visible and in the foreground
`App.Inactive`	App is loaded but not currently visible
`App.Suspended`	App is suspended and may be resumed later

Signals¶

Signal	Description
`lifecycleChanged()`	Emitted when the lifecycle state changes

Usage¶

Display app info¶

SPage {
    title: App.appId

    SCard {
        Layout.fillWidth: true

        SText { text: "App: " + App.appId }
        SText { text: "Version: " + App.appVersion }
        SText { text: "Host: " + App.hostVersion }
    }
}

React to lifecycle changes¶

Connections {
    target: App
    function onLifecycleChanged() {
        if (App.lifecycle === App.Active) {
            refreshData()
        } else if (App.lifecycle === App.Suspended) {
            saveState()
        }
    }
}

Conditional behavior based on lifecycle¶

Timer {
    interval: 5000
    repeat: true
    running: App.lifecycle === App.Active
    onTriggered: fetchUpdates()
}

Implementation Details¶

appId and appVersion are set from the app's manifest.json at launch time
hostVersion is the compile-time version of the Squared host app (CMake PROJECT_VERSION)
Lifecycle transitions are managed by the AppRunner:
- launch() sets Active
- suspend() sets Suspended
- resume() sets Active
- close() destroys the App object