ViewModel creation in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a ViewModel class named MyViewModel.

Android Kotlin

class MyViewModel : [1]() {
}

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AViewModel

BActivity

CFragment

DApplication

Attempts:

3 left

💡 Hint

Common Mistakes

Extending Activity or Fragment instead of ViewModel.

Forgetting to extend any class.

The ViewModel class must extend the ViewModel base class to hold UI data.

2fill in blank

medium

Complete the code to get a ViewModel instance inside an Activity.

Android Kotlin

val viewModel = ViewModelProvider(this).[1](MyViewModel::class.java)

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Abuild

Bget

Ccreate

DnewInstance

Attempts:

3 left

💡 Hint

Common Mistakes

Using create() or newInstance() which do not exist in ViewModelProvider.

Forgetting to pass the ViewModel class.

Use get() to retrieve the ViewModel instance from ViewModelProvider.

3fill in blank

hard

Fix the error in the ViewModel class declaration to use the correct import for ViewModel.

Android Kotlin

import androidx.lifecycle.[1]

class MyViewModel : ViewModel() {
}

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ALifecycleOwner

BViewModelProvider

CViewModel

DLiveData

Attempts:

3 left

💡 Hint

Common Mistakes

Importing ViewModelProvider instead of ViewModel.

Importing unrelated lifecycle classes.

The ViewModel class is imported from androidx.lifecycle.ViewModel.

4fill in blank

hard

Fill both blanks to create a ViewModel with a factory inside a Fragment.

Android Kotlin

val viewModel = ViewModelProvider(this, [1]()).[2](MyViewModel::class.java)

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AMyViewModelFactory

Bget

Ccreate

DViewModelProviderFactory

Attempts:

3 left

💡 Hint

Common Mistakes

Using create() instead of get().

Passing wrong factory class.

Use a custom factory class MyViewModelFactory and call get() to obtain the ViewModel.

5fill in blank

hard

Fill all three blanks to create a ViewModel with saved state support inside an Activity.

Android Kotlin

val viewModel = ViewModelProvider(this, [1](application, [2])).[3](MyViewModel::class.java)

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ASavedStateViewModelFactory

BsavedStateRegistryOwner

Cget

DViewModelStoreOwner

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong factory class.

Forgetting to pass savedStateRegistryOwner.

Using create() instead of get().

Use SavedStateViewModelFactory with the savedStateRegistryOwner and call get() to get the ViewModel.