Use cases / Interactors in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a use case class with an invoke operator function.

Android Kotlin

class GetUserNameUseCase {
    operator fun [1](): String {
        return "Alice"
    }
}

Drag options to blanks, or click blank then click option'

Ainvoke

Bexecute

Crun

Dcall

Attempts:

3 left

💡 Hint

Common Mistakes

Using a regular function name like execute instead of invoke.

The invoke operator allows the use case to be called like a function instance.

2fill in blank

medium

Complete the code to inject a repository into the use case constructor.

Android Kotlin

class GetUserAgeUseCase(private val [1]: UserRepository) {
    operator fun invoke(): Int {
        return repository.getAge()
    }
}

Drag options to blanks, or click blank then click option'

Arepo

BuserRepo

CuserRepository

Drepository

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatch between constructor parameter and usage name.

The parameter name repository matches the usage inside the class.

3fill in blank

hard

Fix the error in the use case function to return the user email from repository.

Android Kotlin

class GetUserEmailUseCase(private val repository: UserRepository) {
    operator fun invoke(): String {
        return repository.[1]()
    }
}

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Aemail

BfetchEmail

CgetEmail

DretrieveEmail

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name that does not exist in the repository.

The repository method to get email is named getEmail().

4fill in blank

hard

Fill both blanks to create a use case that returns true if user is active.

Android Kotlin

class IsUserActiveUseCase(private val [1]: UserRepository) {
    operator fun [2](): Boolean {
        return [1].isActive()
    }
}

Drag options to blanks, or click blank then click option'

Arepository

Binvoke

CuserRepo

Dexecute

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent parameter names or function names.

The constructor parameter is named repository and the function uses the invoke operator.

5fill in blank

hard

Fill all three blanks to define a use case that takes a userId and returns user details.

Android Kotlin

class GetUserDetailsUseCase(private val [1]: UserRepository) {
    operator fun [2](userId: [3]): User {
        return [1].getUserById(userId)
    }
}

Drag options to blanks, or click blank then click option'

Arepository

Binvoke

CInt

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter names or wrong userId type.

The repository parameter is repository, the function is invoke, and the userId is a String.