SharedFlow for event broadcasting in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is SharedFlow in Kotlin?

SharedFlow is a hot flow that allows multiple subscribers to receive the same emitted values, useful for broadcasting events to many collectors.

intermediate

How does SharedFlow differ from StateFlow?

SharedFlow does not hold a current value and is used for events, while StateFlow always holds the latest value and is used for state updates.

intermediate

What does the replay parameter in SharedFlow control?

The replay parameter controls how many past emitted values are buffered and replayed to new subscribers when they start collecting.

beginner

Why is SharedFlow considered a hot flow?

Because it emits values regardless of whether there are active subscribers, unlike cold flows which start emitting only when collected.

beginner

How do you emit an event to a SharedFlow?

You use the emit() or tryEmit() functions on the MutableSharedFlow instance to send events to all subscribers.

What type of flow is SharedFlow in Kotlin?

A Cold flow

B Single emission flow

C State holder

D Hot flow

SharedFlow is a hot flow that emits values regardless of active subscribers.

Which parameter controls how many past events SharedFlow replays to new subscribers?

A capacity

B bufferSize

C replay

D timeout

The replay parameter sets how many past events are replayed to new subscribers.

Which function is used to send an event to a SharedFlow?

A emit()

B launch()

C subscribe()

D collect()

emit() is used to send events to a SharedFlow.

What happens if no subscribers are collecting a SharedFlow when an event is emitted?

A Event is lost

B Event is buffered if replay > 0

C Flow stops

D Exception is thrown

Events are buffered up to the replay count and delivered to future subscribers.

Which of these is NOT a typical use case for SharedFlow?

A Holding the latest state value

B Broadcasting UI events

C Sending one-time notifications

D Sharing events between multiple collectors

Holding the latest state value is the role of StateFlow, not SharedFlow.

Explain how SharedFlow helps in broadcasting events to multiple subscribers in Kotlin.

Think about how events are sent and received by many listeners at once.

Describe the difference between SharedFlow and StateFlow and when you would use each.

Consider if you want to hold a value or just send events.