What are Keys in Flutter and why are they critical?
Source: api.flutter.devadvanced
Tests widget identity during reconciliation. Keys let Flutter distinguish moved widgets from changed data; without ValueKeys, ReorderableListView leaves state at old positions, e.g., a checkbox swap. Red flag: calling them performance tools.
Tests deep understanding of Flutter's element reconciliation. A strong answer defines Keys as identity tokens that override type-and-position matching during the Element diff. It explains that ReorderableListView requires Keys because dragging changes widget positions; without ValueKeys, Flutter recycles Elements and State by slot index, so state sticks to the wrong position.
Read the original → api.flutter.dev
- #flutter
- #keys
- #state-management
- #reorderablelistview
- #widget-lifecycle
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