Flow basics in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple Flow that emits numbers from 1 to 3.

Android Kotlin

val numbersFlow = flow {
    for (i in 1..[1]) {
        emit(i)
    }
}

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

A0

B5

C10

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 as the upper bound results in no emissions.

Using 5 or 10 emits more numbers than required.

The flow emits numbers from 1 to 3, so the range should be 1..3.

2fill in blank

medium

Complete the code to collect and print each value emitted by the Flow.

Android Kotlin

numbersFlow.[1] { value ->
    println(value)
}

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

Amap

Bcollect

ClaunchIn

Dfilter

Attempts:

3 left

💡 Hint

Common Mistakes

Using launchIn without a CoroutineScope causes errors.

Using map or filter does not collect values.

To receive and handle emitted values from a Flow, use the collect function.

3fill in blank

hard

Fix the error in the code to emit strings instead of integers.

Android Kotlin

val stringFlow = flow {
    for (i in 1..3) {
        emit([1])
    }
}

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

Ai.toString()

Bi

C"i"

Di + ""

Attempts:

3 left

💡 Hint

Common Mistakes

Emitting i emits integers, not strings.

Using "i" emits the literal letter i, not the number.

To emit strings, convert the integer i to string using toString().

4fill in blank

hard

Fill both blanks to create a Flow that emits only even numbers from 1 to 5.

Android Kotlin

val evenFlow = flow {
    for (num in 1..5) {
        if (num [1] 2 == 0) {
            emit(num[2])
        }
    }
}

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

A%

B*

C+

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using * or + in the if condition causes wrong checks.

Adding operators after emit(num) causes syntax errors.

The modulo operator % checks if a number is even by testing remainder 0. The emit function just emits the number as is, so no operator needed after num.

5fill in blank

hard

Fill all three blanks to create a Flow that emits squares of numbers greater than 2 from 1 to 4.

Android Kotlin

val squaresFlow = flow {
    for (x in 1..4) {
        if (x [1] 2) {
            emit(x [2] x)
        }
    }
}

squaresFlow.collect { value ->
    println(value [3] 0)
}

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

A>

B*

C>=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using >= instead of > changes the condition.

Using == in the print condition prints false instead of true.

We check if x is greater than 2 using >. Then emit the square by multiplying x by x. Finally, print whether each value is greater than 0.