Room with Coroutines in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Room in Android development?

Room is a library that provides an abstraction layer over SQLite to allow fluent database access while harnessing the full power of SQLite.

beginner

Why use Coroutines with Room?

Coroutines help perform database operations asynchronously without blocking the main thread, keeping the app responsive.

intermediate

What keyword is used to mark a DAO method as a suspend function?

You use the 'suspend' keyword in Kotlin before the function declaration to mark it as a suspend function for coroutines.

intermediate

How does Room support returning LiveData or Flow?

Room can return LiveData or Flow objects from DAO queries to automatically update the UI when data changes, integrating with coroutines and lifecycle.

beginner

What is the benefit of marking DAO functions with 'suspend'?

Marking DAO functions with 'suspend' allows them to be called from coroutines, enabling non-blocking database operations.

Which keyword is used in Kotlin to make a Room DAO function asynchronous with coroutines?

A await

B async

C defer

D suspend

The 'suspend' keyword marks a function as suspendable, allowing it to be called from coroutines for asynchronous execution.

What does Room provide over SQLite?

A An abstraction layer for easier database access

B A graphical user interface

C Automatic network synchronization

D Built-in cloud storage

Room provides an abstraction layer over SQLite to simplify database operations while keeping full SQLite power.

Which of these is a recommended way to observe database changes with Room and coroutines?

A Returning LiveData or Flow from DAO queries

B Using callbacks only

C Polling the database every second

D Using Thread.sleep()

Returning LiveData or Flow allows automatic updates to UI when data changes, integrating well with coroutines.

What happens if you call a suspend DAO function on the main thread without coroutines?

A It runs asynchronously automatically

B It blocks the UI thread

C It crashes the app

D It runs on a background thread by default

Calling suspend functions without proper coroutine context can block the main thread, causing UI freezes.

Which coroutine builder is commonly used to call suspend Room DAO functions from a ViewModel?

A runBlocking

B async

C launch

D delay

The 'launch' builder starts a coroutine without blocking the main thread, suitable for calling suspend DAO functions.

Explain how Room and Kotlin coroutines work together to perform database operations without freezing the UI.

Think about how suspend functions and coroutine scopes help keep the app responsive.

Describe how you would observe changes in a Room database using Kotlin Flow and update the UI accordingly.

Consider how Flow streams data and how to collect it safely in UI components.