Why Kotlin is the official Android language in Android Kotlin - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a simple Kotlin function that prints a greeting.

Android Kotlin

fun greet() {
    println([1])
}

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

A"Hello, Android!"

BHello, Android!

Cprintln("Hello, Android!")

Dprint("Hello, Android!")

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string

Trying to call print inside println

The println function requires a string argument in quotes to print text. So, "Hello, Android!" is correct.

2fill in blank

medium

Complete the code to declare a Kotlin variable that cannot be changed.

Android Kotlin

val language: String = [1]

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A"Kotlin"

BKotlin

Ckotlin

D'Kotlin'

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes instead of double quotes

Not using quotes at all

String values must be in double quotes in Kotlin. val means the variable is read-only.

3fill in blank

hard

Fix the error in the Kotlin function that returns the length of a string.

Android Kotlin

fun lengthOf(text: String): Int {
    return text.[1]
}

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Alength()

Bcount()

Csize()

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using length() with parentheses causes an error

Using size() which is not a String property

In Kotlin, String length is a property accessed without parentheses: text.length

4fill in blank

hard

Fill both blanks to create a Kotlin list and print its size.

Android Kotlin

val fruits = listOf([1])
println(fruits.[2])

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A"Apple", "Banana", "Cherry"

Bsize()

Csize

D"Apple"

Attempts:

3 left

💡 Hint

Common Mistakes

Using size() with parentheses causes error

Passing a single string instead of multiple elements

listOf takes elements as arguments. size is a property to get the list length.

5fill in blank

hard

Fill all three blanks to create a Kotlin data class and instantiate it.

Android Kotlin

data class [1](val name: String, val age: Int)
val person = [2]([3], 30)

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

APerson

BPerson()

C"Alice"

Attempts:

3 left

💡 Hint

Common Mistakes

Using Person() as class name

Not using quotes around the string argument

Define data class Person, then create instance with Person("Alice", 30).