Performance
How does using const constructors improve Flutter performance?
const widgets are canonicalized at compile time — Flutter creates them once and reuses the same instance. W...
10 XP2m
Performance
15 questions
Rebuild optimization, memory leaks, DevTools
Performance
What is RepaintBoundary and when should you use it?
RepaintBoundary creates a new compositor layer, isolating its subtree from parent repaints. Use it around c...
30 XP3m
Performance
Why should you use ListView.builder instead of ListView for large lists?
ListView.builder builds only the visible items lazily. ListView() with a children: list builds all items up...
10 XP2m
Performance
How does Flutter handle image caching and how can you optimize it?
Flutter's ImageCache holds decoded bitmaps in memory (default: 100MB or 1000 images). For network images, u...
30 XP4m
Performance
How do you profile Flutter app performance with DevTools?
Use Flutter DevTools' Performance tab to record a trace, identify janky frames (>16ms for 60Hz), and pinpoi...
30 XP4m
Performance
Why should you avoid calling BuildContext.of() methods in build() repeatedly?
Each Theme.of(context), MediaQuery.of(context), etc. call walks up the element tree to find the nearest Inh...
30 XP3m
Performance
What is shader compilation jank and how do you fix it?
Shader compilation jank is a dropped frame that occurs the first time Flutter renders a new visual effect (...
50 XP4m
Performance
When should you use an Isolate for performance?
Move CPU-intensive work (JSON parsing, image processing, encryption, sorting large lists) to an Isolate usi...
50 XP4m
Performance
How do you detect and fix memory leaks in Flutter?
Common leaks: not canceling StreamSubscriptions, not disposing AnimationControllers/TextEditingControllers,...
40 XP5m
Performance
How do you optimize image loading and caching in Flutter?
Use cached_network_image for automatic disk+memory caching. Always set cacheWidth/cacheHeight to decode at ...
30 XP4m
Performance
What are Flutter build modes and how do they affect performance?
Debug: JIT compilation, hot reload, all assertions enabled — slowest (60-70% slower than release). Profile:...
20 XP3m
Performance
How does Flutter's rendering pipeline work?
Flutter renders via three threads: UI thread (Dart, builds widget/element/render trees, layout, paint), Ras...
50 XP6m
Performance
How do you build performant lists and grids in Flutter?
Always use ListView.builder / GridView.builder for dynamic lists — they lazily build only visible items. Ne...
30 XP4m
Performance
What is shader compilation jank and how do you fix it?
Shader compilation jank: the first time an animation runs, the GPU compiles the shader on-the-fly, causing ...
50 XP5m
Performance
How do you optimize Flutter app startup time?
Reduce startup time: defer heavy initialization (analytics, database) to post-startup, use lazy-singleton s...
40 XP5m