sdk/dart/package-fuchsia_modular_lifecycle/Lifecycle/enableLifecycleEvents.md

# enableLifecycleEvents method




    *[<Null safety>](https://dart.dev/null-safety)*




void enableLifecycleEvents
([Outgoing](../../package-fuchsia_services_services/Outgoing-class.md) outgoing)





<p>Initializes the shared <a href="../../package-fuchsia_modular_lifecycle/Lifecycle-class.md">Lifecycle</a> instance. This is required before
Lifecycle can be constructed.</p>



## Implementation

```dart
static void enableLifecycleEvents(Outgoing outgoing) {
  if (_singleton == null) {
    _singleton = LifecycleImpl(
      outgoing: outgoing,
      exitHandler: fuchsia.exit,
    );
  } else {
    throw Exception(
        'Attempted to call Lifecycle.enableLifecycleEvents after it has already been enabled. '
        'Ensure that Lifecycle.enableLifecycleEvents is not called multiple times.');
  }
}
```