Question 1

What is the difference between StatelessWidget and StatefulWidget?

Accepted Answer

A StatelessWidget is immutable and rebuilds only when its parent rebuilds; a StatefulWidget holds mutable state via a separate State object and can rebuild itself whenever that state changes.

Question 2

What is Flutter?

Accepted Answer

Flutter is Google's open-source UI toolkit for building natively compiled apps for mobile, web, and desktop from a single Dart codebase.

Question 3

Explain the widget lifecycle in Flutter.

Accepted Answer

A StatefulWidget's State goes through createState → initState → didChangeDependencies → build (repeated) → didUpdateWidget (on parent rebuild) → deactivate → dispose.

Question 4

Describe Flutter's architecture — how does a widget end up as pixels on screen?

Accepted Answer

Flutter has three parallel trees Widget, Element, and RenderObject where widgets are immutable configuration, elements are the mutable instances that manage the tree, and render objects handle layout, painting, and hit-testing.

Flutter Fundamentals Flutter Interview Questions

What is the difference between StatelessWidget and StatefulWidget?

What is Flutter?

Explain the widget lifecycle in Flutter.

Describe Flutter's architecture — how does a widget end up as pixels on screen?