Flutter Prague #7

What happens if you use setState() in StatefulWidget and don't change any data?

• The build() function is not called

• The build() function is called again even though the data has not changed

• Compilation fails

• Flutter optimizes it and skips the rebuild

What causes a memory leak?

• Failure to call super.dispose()

• Too much setState()

• Using the const widget

• StatefulWidget without createState

What is the validity of BuildContext in async operations in build()?

• The context remains valid

• It may be deprecated - it is dangerous to use

• It is guaranteed by Flutter

• Cannot be used in async functions

What is correct?

• This code won’t compile

• You cannot use factory in an abstract class

• This is valid and will instantiate Circle

• You must implement Shape with extends, not implements

Which of these applications IS NOT written in Flutter?

• Můj T-Mobile

• About You

• Fakturoid

• Discord

Consider this Swift plugin and its Flutter representation. What is the output of getId()?

• 1

• 2

• error

Consider the following class, what happens when calling getFirst ?

• Null is returned

• Exception is thrown

• Compilation error

Consider the following class, what happens when calling getFirst ?

• Null is returned

• Exception is thrown

• Compilation error