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

Combining UI code and backend logic

Storing all data in the ViewModel

Dividing different responsibilities into separate modules

Keeping all code in a single activity class

None

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

It persists, maintaining the state data

It is destroyed and recreated with the activity

It is stored in the device’s local database

It automatically stores data to shared preferences

None

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

Performing network calls or database operations

Defining UI layouts

Handling user input directly

Managing UI navigation

None

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

LiveData can only be used with ViewModel

LiveData is faster than using state variables

LiveData replaces the need for data binding

LiveData automatically updates the UI when data changes

None

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

It returns an existing ViewModel instance if one is already created

It always creates a new instance of a ViewModel

It can be used to observe changes in data directly

It handles network requests

None

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

viewModel()

rememberViewModel()

createViewModel()

getViewModel()

None

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

It keeps the ViewModel active after the activity is destroyed

It manages lifecycle of UI components

It enhances the speed of recomposition

It automatically cancels tasks when the ViewModel is cleared

None

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

androidx.activity:activity-compose

androidx.compose.ui:ui

androidx.lifecycle:lifecycle-viewmodel-compose

androidx.compose.runtime:runtime-livedata

None

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

observeAsState()

liveDataToState()

stateFromLiveData()

stateObserver()

None

10.

What is the purpose of the observeAsState() function?

To create a new ViewModel

To convert LiveData into a Compose state object

To update the UI without recomposition

To manage the lifecycle of an activity

None

11.

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

To manage user interface elements directly

To handle database interactions

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

To design the layout of an Android app

None

12.

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

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

It cannot be used with navigation components

It creates a new ViewModel instance every time

It requires a unique key to be used

None

13.

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

To ensure that the UI and data are tightly coupled

To allow child Composables to access and observe the state easily

To minimize the number of Composables in an app

To avoid creating multiple instances of the ViewModel

None

14.

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

At the root level of the Composable hierarchy

Inside a child Composable function

Inside a coroutine function

In the MainActivity’s onCreate method

None

15.

How is a MutableState in Compose different from MutableLiveData?

MutableLiveData can only be used with Compose

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

MutableState can store complex data types like JSON directly

MutableState persists data across configuration changes automatically

None

16.

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

Changes to the ViewModel state data

Initialization of the ViewModel

Launching a new activity

Using the viewModel() function

None

17.

Which statement about MutableLiveData is correct?

It allows observing data changes within a ViewModel

It is exclusive to the Compose framework

It is used to observe UI elements in real-time

It can be used to store large files in memory

None

18.

When should you use the MutableLiveData class in a ViewModel?

When you want to store observable data that predates Compose

When you want to observe changes in data using Compose state

When you need to implement animations

When you need to handle user input events directly

None

19.

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

It merges UI logic with data handling in a single module

It separates different areas of functionality into distinct modules

It combines multiple activities into one

It focuses on integrating third-party libraries

None

20.

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

ViewModel

LiveData

DataBinding

Activity Navigation

None

21.

How does the ViewModel help with activity lifecycle management?

It prevents activities from being destroyed

It controls the lifecycle of fragments

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

It directly handles activity recreation

None

22.

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

Apps with no separation between UI and data logic

Using only fragments for UI management

Single activity apps with separated responsibilities

None

23.

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

It stores the layout design

It manages background tasks

It handles error logging

It holds the current state value that triggers UI recompositions

None

24.

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

It enables direct interaction with Android services

It helps maintain data consistency during configuration changes

It speeds up UI rendering

It directly controls the UI layout

None

Time’s up

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