Why are keys used in Flutter and what role do they play in widget management?

In Flutter, Keys are used to identify widgets in the widget tree, especially when widgets of the same type are reordered or updated.

Roles of keys:

• Preserving state: Flutter uses keys to match widgets with their state during rebuilds.
• Optimizing updates: Keys help Flutter efficiently update only changed parts of the UI.
• Managing uniqueness: When multiple widgets of the same type are in a list, keys distinguish them.

Example:

ListView(
  children: items.map((item) => ListTile(
    key: ValueKey(item.id),
    title: Text(item.name),
  )).toList(),
)

Here, ValueKey helps Flutter correctly associate widgets with data during list changes.