Side effects (LaunchedEffect, SideEffect) in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to launch a side effect when the composable enters the composition.

Android Kotlin

LaunchedEffect([1]) {
    // Your suspend function here
}

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

Afalse

Btrue

CUnit

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using true or false as keys which might cause unexpected restarts.

Using null which is not allowed as a key.

LaunchedEffect requires a key to control when it runs. Using Unit means it runs once when the composable enters composition.

2fill in blank

medium

Complete the code to run a side effect every time the count value changes.

Android Kotlin

LaunchedEffect([1]) {
    println("Count changed: $count")
}

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

Acount

Btrue

CUnit

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using true or Unit which do not depend on count.

Using null which is invalid.

Passing count as the key makes the effect run every time count changes.

3fill in blank

hard

Fix the error in the code to correctly run a side effect that updates the UI after composition.

Android Kotlin

SideEffect {
    [1] = true
}

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

Aval isLoading

BisLoading

Cvar isLoading

Dfun isLoading

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to declare variables inside SideEffect block.

Using val or fun keywords inside the block.

You should assign to an existing mutable state variable like isLoading. Declaring it inside SideEffect is incorrect.

4fill in blank

hard

Fill both blanks to create a side effect that runs only once and updates a flag.

Android Kotlin

LaunchedEffect([1]) {
    [2] = true
}

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

AUnit

Bfalse

CisInitialized

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using true or false as keys causing repeated runs.

Assigning to a wrong or undeclared variable.

Using Unit as key runs the effect once. Assigning true to isInitialized updates the flag.

5fill in blank

hard

Fill all three blanks to create a side effect that updates a message when userName changes.

Android Kotlin

LaunchedEffect([1]) {
    message = "Hello, " + [2] + [3]
}

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

AuserName

B"!"

D"?"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong keys causing the effect not to run on userName change.

Using a question mark instead of an exclamation mark.

The effect runs when userName changes. The message concatenates userName and an exclamation mark.