Compose ViewModel Quiz

This set of multiple-choice questions focuses on the role of the ViewModel in Android architecture, particularly in conjunction with Jetpack Compose. It explores key concepts such as state management, lifecycle handling, separation of concerns, and the use of functions like viewModel() and observeAsState() for integrating ViewModel data into Composable functions. By understanding these concepts, developers can effectively manage UI-related data, maintain consistency across configuration changes, and ensure clean separation between UI logic and data handling in their Android applications.

Which function is used to create or access a ViewModel instance in a Composable?

rememberViewModel()

createViewModel()

getViewModel()

viewModel()

None

How does the ViewModel help with activity lifecycle management?

It directly handles activity recreation

It controls the lifecycle of fragments

It prevents activities from being destroyed

It ensures that data is persisted even when an activity is recreated

None

What role does the 'separation of concerns' concept play in Android app architecture?

It combines multiple activities into one

It focuses on integrating third-party libraries

It merges UI logic with data handling in a single module

It separates different areas of functionality into distinct modules

None

Which Compose library function converts a LiveData object into a State object?

liveDataToState()

stateObserver()

observeAsState()

stateFromLiveData()

None

How does a ViewModel instance behave when an activity is recreated?

It automatically stores data to shared preferences

It is stored in the device’s local database

It is destroyed and recreated with the activity

It persists, maintaining the state data

None

What is the primary benefit of using LiveData with ViewModel in a non-Compose Android app?

LiveData replaces the need for data binding

LiveData is faster than using state variables

LiveData automatically updates the UI when data changes

LiveData can only be used with ViewModel

None

Which of the following is a key principle of modern Android architecture recommended by Google?

Multiple activity-based apps with mixed UI and data logic

Single activity apps with separated responsibilities

Apps with no separation between UI and data logic

Using only fragments for UI management

None

Which of the following best describes 'separation of concerns' in Android architecture?

Dividing different responsibilities into separate modules

Keeping all code in a single activity class

Combining UI code and backend logic

Storing all data in the ViewModel

None

What is a common use case for the viewModelScope in a ViewModel?

Managing UI navigation

Handling user input directly

Defining UI layouts

Performing network calls or database operations

None

10.

Which statement about MutableLiveData is correct?

It is used to observe UI elements in real-time

It allows observing data changes within a ViewModel

It can be used to store large files in memory

It is exclusive to the Compose framework

None

11.

What role does the MutableState object play in a ViewModel with Compose?

It manages background tasks

It handles error logging

It stores the layout design

It holds the current state value that triggers UI recompositions

None

12.

In a ViewModel, what triggers the recomposition of the UI?

Using the viewModel() function

Launching a new activity

Initialization of the ViewModel

Changes to the ViewModel state data

None

13.

What dependency must be added to use the Compose viewModel() function?

androidx.compose.runtime:runtime-livedata

androidx.activity:activity-compose

androidx.lifecycle:lifecycle-viewmodel-compose

androidx.compose.ui:ui

None

14.

What is the purpose of the observeAsState() function?

To create a new ViewModel

To manage the lifecycle of an activity

To update the UI without recomposition

To convert LiveData into a Compose state object

None

15.

When should you use the MutableLiveData class in a ViewModel?

When you want to observe changes in data using Compose state

When you want to store observable data that predates Compose

When you need to implement animations

When you need to handle user input events directly

None

16.

Which of the following statements is true about the viewModel() function?

It shares a ViewModel instance with all Composables in the same scope

It creates a new ViewModel instance every time

It requires a unique key to be used

It cannot be used with navigation components

None

17.

What is the primary purpose of the ViewModel component in Android architecture?

To manage user interface elements directly

To store and manage UI-related data separately from UI logic

To handle database interactions

To design the layout of an Android app

None

18.

When using a ViewModel with Compose, where is the best place to initialize the ViewModel?

Inside a coroutine function

At the root level of the Composable hierarchy

Inside a child Composable function

In the MainActivity’s onCreate method

None

19.

Why is it recommended to initialize a ViewModel in a top-level Composable?

To minimize the number of Composables in an app

To avoid creating multiple instances of the ViewModel

To allow child Composables to access and observe the state easily

To ensure that the UI and data are tightly coupled

None

20.

Which of the following is true about the viewModel() function?

It returns an existing ViewModel instance if one is already created

It can be used to observe changes in data directly

It always creates a new instance of a ViewModel

It handles network requests

None

21.

How is a MutableState in Compose different from MutableLiveData?

MutableState is specific to Compose and used for state management within Composables

MutableState persists data across configuration changes automatically

MutableState can store complex data types like JSON directly

MutableLiveData can only be used with Compose

None

22.

What is the key benefit of using ViewModel with a Compose UI?

It speeds up UI rendering

It directly controls the UI layout

It helps maintain data consistency during configuration changes

It enables direct interaction with Android services

None

23.

Which architecture component is still relevant in modern Android app development with Compose?

Activity Navigation

DataBinding

ViewModel

LiveData

None

24.

Why is it important to use viewModelScope when performing background tasks?

It keeps the ViewModel active after the activity is destroyed

It automatically cancels tasks when the ViewModel is cleared

It manages lifecycle of UI components

It enhances the speed of recomposition

None

Time’s up

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