When developing with Flutter, performance optimization is critical for ensuring smooth app performance. There are many fine-tuning aspects to consider, from minimizing widget rebuilds to key points to watch in animations. It's interesting to see how effective `ListView.builder` is for lists. In your opinion, what other techniques can be used to boost performance? Perhaps even special approaches related to state management could come into play here.
What are the best practices for performance optimization in Flutter?
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In addition to lists, using `const` constructors also significantly reduces widget rebuilds, you say. But before using `const`, how much of your widgets can you actually optimize?
Is ListView.builder great? Absolutely. But can we optimize layout phases in complex screens with ConstraintLayout-like widgets? How do we minimize performance losses when dealing with nested Rows/Columns?
Using `ListView.builder` is a great start; I've also encountered the same issue with long lists. Prefixing widgets with `const` reduces rebuilds, and using `RepaintBoundary` prevents unnecessary renders—both are very effective. Additionally, running heavy computations in the background with `Isolate` significantly boosts performance.
Using `const` constructors is probably the simplest and most effective way to reduce widget rebuilds. For simple animations, I’d also lean toward widgets like `AnimatedOpacity` instead of `Opacity` to keep performance smooth.
I also had a pretty heated battle with performance optimization in Flutter last year while developing a large e-commerce app. In the project, users were complaining about "janky scrolling" and "delayed loading." We initially used a simple `ListView`, which made the app nearly unusable when there were 100+ products in the list. My friend and I implemented `ListView.builder`, and the initial results were promising—scrolling performance improved by 40%. But the real breakthrough came when we added `const` keywords to widgets. Suddenly, the number of builds halved, and CPU usage dropped significantly.
Then we dove into optimizing animations and entered a whole new world. I still remember the unstable window transitions before we used `Hero` widgets—users complained about screen freezes while scrolling. After adding `RepaintBoundary` to the widget tree and optimizing animations, we hit 60fps in just 3 days. At least we learned to prefer low-cost animations like `Opacity` and `Transform`.
The real challenge, though, was state management. While `setState` worked fine for simple projects, as the app grew, widget rebuilds spiraled out of control. That’s when I compared `Riverpod` and `Provider` for optimizations—especially using selective listening and `family` models, which reduced unnecessary rebuilds by 70%. Overall, the philosophy for performance optimization should be: "First, identify what’s causing the problem, then fix it."