Avoiding Memory Leaks in Flutter
Memory leaks aren’t always obvious—but they can slow apps down or crash them after long usage. Many are due to simple oversights like forgetting to dispose().
🧠 Common Memory Leak Causes
- Controllers like
TextEditingController,AnimationControllernot disposed
- Streams still listening after screen changes
- Listeners bound outside of widget lifecycle
✅ 5 Steps to Prevent Memory Leaks
1. Always Dispose of Controllers
@override
void dispose() {
controller.dispose();
super.dispose();
}
2. Use StatefulWidget Carefully
Stateless widgets don’t hold state—avoid attaching listeners or holding resources inside them.
3. Cancel Subscriptions
Cancel StreamSubscription in dispose() or use StreamBuilder which handles cleanup automatically.
4. Use WidgetsBindingObserver Properly
If using lifecycle events, unregister observers to prevent hidden leaks.
5. Test with DevTools Memory Tab
Check for retained objects or instances that shouldn’t persist after widget disposal.
🧼 Conclusion
Managing lifecycle and cleanup is vital in mobile apps. Good memory hygiene improves stability and user trust.