First Android app in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to display a simple text in the app's main screen.

Android Kotlin

setContentView(R.layout.[1])

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

Aactivity_main

Bmain_activity

Clayout_main

Dmain_layout

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong layout file name.

Confusing the layout resource with other resource types.

The layout file for the main screen is usually named activity_main.xml. We use R.layout.activity_main to set it as the content view.

2fill in blank

medium

Complete the code to find a TextView by its ID and set its text.

Android Kotlin

val textView = findViewById<TextView>(R.id.[1])
textView.text = "Hello, Android!"

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

Amain_text

BtextView

Chello_text

Dtext_view

Attempts:

3 left

💡 Hint

Common Mistakes

Using camelCase instead of snake_case for IDs.

Using the wrong ID name.

The ID of the TextView in the layout is text_view. We use R.id.text_view to find it.

3fill in blank

hard

Fix the error in the code to correctly set the text of a TextView.

Android Kotlin

val textView = findViewById<TextView>(R.id.text_view)
textView.[1] = "Welcome!"

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

Atext

BsetText

Cset_text

DText

Attempts:

3 left

💡 Hint

Common Mistakes

Using Java style setText() method in Kotlin.

Using incorrect property names.

In Kotlin, to set the text of a TextView, we assign a string to its text property.

4fill in blank

hard

Fill both blanks to create a button click listener that changes the TextView text.

Android Kotlin

val button = findViewById<Button>(R.id.button)
button.setOnClickListener {
    val textView = findViewById<TextView>(R.id.[1])
    textView.[2] = "Button clicked!"
}

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

Atext_view

BsetText

Ctext

Dbutton_text

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong ID for the TextView.

Using Java style setText() instead of Kotlin property.

The TextView ID is text_view and to change its text in Kotlin, we assign to the text property.

5fill in blank

hard

Fill all three blanks to create a simple app that updates a TextView when a button is clicked.

Android Kotlin

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.[1])

        val button = findViewById<Button>(R.id.[2])
        button.setOnClickListener {
            val textView = findViewById<TextView>(R.id.[3])
            textView.text = "Clicked!"
        }
    }
}

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

Aactivity_main

Bbutton

Ctext_view

Dmain_activity

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up layout and view IDs.

Forgetting to set the content view before finding views.

The layout file is activity_main. The button ID is button and the TextView ID is text_view. This setup updates the TextView text when the button is clicked.