isLineAppInstalled

Whether the LINE app is installed on this device.

For deciding what to show, not whether to offer a login: login works either way, going app-to-app when LINE is present and falling back to a browser when it is not. Use it to label a button, to explain the flow the user is about to see, or to record which path a failing login took.

Needs no configuration, so it may be called before configure.

On iOS this requires lineauth2 in your Info.plist under LSApplicationQueriesSchemes — the same entry app-to-app login needs. Without it iOS answers false on every device, so a false here on a phone that visibly has LINE means that key is missing rather than that LINE is.

On Android it uses the application Context this library picks up through androidx.startup. If your app strips that provider, use the Android-only isLineAppInstalled(context) overload instead, which takes one directly.

On web a page cannot see the device's app list, so this answers true only when the page is running inside the LINE app's own browser, and false everywhere else — including before configure has loaded the SDK.