didUpdateWidget method
- @mustCallSuper
- @protected
- covariant MissileSitePage oldWidget
Called whenever the widget configuration changes.
If the parent widget rebuilds and request that this location in the tree
update to display a new widget with the same runtimeType and
Widget.key, the framework will update the widget property of this
State object to refer to the new widget and then call this method
with the previous widget as an argument.
Override this method to respond when the widget changes (e.g., to start implicit animations).
The framework always calls build after calling didUpdateWidget, which means any calls to setState in didUpdateWidget are redundant.
If a State's build method depends on an object that can itself
change state, for example a ChangeNotifier or Stream, or some
other object to which one can subscribe to receive notifications, then
be sure to subscribe and unsubscribe properly in initState,
didUpdateWidget, and dispose:
- In initState, subscribe to the object.
- In didUpdateWidget unsubscribe from the old object and subscribe to the new one if the updated widget configuration requires replacing the object.
- In dispose, unsubscribe from the object.
If you override this, make sure your method starts with a call to super.didUpdateWidget(oldWidget).
Implementation
@mustCallSuper
@protected
void didUpdateWidget(covariant T oldWidget) { }