1) Why Flutter Has a Lifecycle for Stateful Widgets

In Flutter, widgets are lightweight configuration objects, while the State object is persistent across rebuilds. This separation is why State has a lifecycle: the framework can rebuild the UI many times while keeping your state (data, controllers, subscriptions) alive as needed.

A StatefulWidget creates a State object once (per insertion), and Flutter drives the State through key lifecycle callbacks as it mounts, rebuilds, updates, and unmounts.

2) The Core Lifecycle Phases (What Runs, When, and Why)

A) Creation

createState()

• Called when the framework needs a new State instance for your StatefulWidget.
• Your persistent variables live in the State object, not the widget.

B) Initialization

initState()

• Called exactly once for each State object, right after it’s mounted.
• Best place to initialize:
  • Controllers (e.g., AnimationController, TextEditingController)
  • Subscriptions / listeners (streams, notifiers)
  • One-time startup logic
• Important rule: don’t depend on inherited widgets from context here; use didChangeDependencies() for that.

didChangeDependencies()

• Called right after initState() the first time.
• Called again whenever a dependency changes (e.g., InheritedWidget / Provider-based dependencies).
• Safe place to read dependency-driven values using context.