Google Flutter App Development 3

Question 1

What is the key difference between StatelessWidget and StatefulWidget?

Accepted Answer

StatefulWidget can rebuild when its mutable state changes

Answer

StatelessWidget cannot have children

Answer

StatelessWidget renders faster always

Answer

StatefulWidget cannot use build()

Question 2

Which method triggers a rebuild after changing state in a StatefulWidget?

Accepted Answer

setState()

Answer

rebuild()

Answer

notify()

Answer

update()

Question 3

Where should you typically dispose of controllers like AnimationController?

Accepted Answer

In the dispose() method of the State

Answer

In build()

Answer

In initState()

Answer

In the constructor

Question 4

Which lifecycle method runs once when a State object is first created?

Accepted Answer

initState()

Answer

build()

Answer

didUpdateWidget()

Answer

dispose()

Question 5

What is a BuildContext primarily used for?

Accepted Answer

Locating a widget's position in the tree to access inherited widgets

Answer

Storing app data

Answer

Running network requests

Answer

Compiling Dart code

Question 6

Why are most Flutter widgets immutable?

Accepted Answer

So the framework can efficiently rebuild and diff the tree

Answer

To save memory only

Answer

Because Dart forbids mutation

Answer

To avoid using state

Question 7

What does the 'const' keyword on a widget constructor enable?

Accepted Answer

Compile-time constant widgets that Flutter can skip rebuilding

Answer

Faster network calls

Answer

Automatic state management

Answer

Larger app size