Creating a new Android project in Android Kotlin - Practice Exercises

Challenge - 5 Problems

❓ ui_behavior

intermediate

What is the default launcher activity in a new Android project?

When you create a new Android project in Android Studio with the default settings, which activity is set as the launcher activity that opens first when the app starts?

A HomeActivity

B SplashActivity

C MainActivity

D LoginActivity

💡 Hint

Think about the activity Android Studio creates automatically for you.

The default activity created by Android Studio in a new project is named MainActivity and it is set as the launcher activity in the manifest.

❓ lifecycle

intermediate

What lifecycle method is called first when the app starts?

In the default MainActivity of a new Android project, which lifecycle method is called first when the app is launched?

A onCreate()

B onStart()

C onResume()

D onDestroy()

💡 Hint

This method is where you usually set your layout.

The onCreate() method is the first lifecycle callback called when the activity is created and is where you initialize your UI.

📝 Syntax

advanced

Which Kotlin code snippet correctly sets the content view in MainActivity?

In the MainActivity.kt file of a new Android project, which code correctly sets the layout resource named activity_main as the content view?

Android Kotlin

class MainActivity : AppCompatActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    // Set content view here
  }
}

A setContentView("activity_main")

B setContentView(R.layout.activity_main)

C setContentView(R.id.activity_main)

D setContentView(layout.activity_main)

💡 Hint

The layout resource is accessed via R.layout.

The correct way to set the layout is using setContentView(R.layout.activity_main). Using R.id or strings will cause errors.

❓ navigation

advanced

What happens if you forget to declare MainActivity in AndroidManifest.xml?

If you create MainActivity.kt but do not add it to AndroidManifest.xml, what will happen when you try to run the app?

A The app crashes with ActivityNotFoundException at startup

B The app runs but shows a blank screen

C The app runs normally without issues

D The app shows a compile-time error

💡 Hint

Android needs to know which activity to launch first.

If MainActivity is not declared in the manifest, the system cannot find the launcher activity and throws ActivityNotFoundException at runtime.

🧠 Conceptual

expert

Why does Android Studio create a Gradle build file in a new project?

When you create a new Android project, Android Studio generates build.gradle files. What is the main purpose of these Gradle files?

A To define AndroidManifest.xml contents

B To store user interface layouts

C To write Kotlin code for activities

D To manage project dependencies and build configurations

💡 Hint

Think about how the app knows which libraries to include and how to compile.

Gradle build files tell Android Studio how to compile the app and which libraries to include, managing dependencies and build settings.

Practice

1. What is the first step when creating a new Android project in Android Studio?

easy

A. Create a new Java file manually

B. Write Kotlin code directly without any setup

C. Download an app from the Play Store

D. Open Android Studio and select 'New Project' from the welcome screen

Solution

1. Step 1: Open Android Studio

   You start by launching Android Studio, the official tool for Android development.

2. Step 2: Select 'New Project'

   From the welcome screen, you choose 'New Project' to begin setting up your app.

3. Final Answer:

   Open Android Studio and select 'New Project' from the welcome screen -> Option D

4. Quick Check:

   First step = Open Android Studio and start new project [OK]

Hint: Always start by opening Android Studio and choosing 'New Project' [OK]

Common Mistakes:

• Trying to write code before creating a project
• Skipping Android Studio and using other tools
• Downloading apps instead of creating one

2. Which language should you select when creating a new Android project to use Kotlin?

easy

A. Kotlin

B. Java

C. C++

D. Python

Solution

1. Step 1: Choose the programming language option

   During project setup, Android Studio asks which language to use for your app.

2. Step 2: Select Kotlin for modern Android development

   Kotlin is the recommended language for Android apps, so you pick Kotlin here.

3. Final Answer:

   Kotlin -> Option A

4. Quick Check:

   Language choice = Kotlin [OK]

Hint: Pick Kotlin language option to write Android apps [OK]

Common Mistakes:

• Choosing Java instead of Kotlin
• Selecting unsupported languages like Python
• Not selecting any language

3. After creating a new Android project with an Empty Activity template, what will the default screen show when you run the app?

medium

A. A screen showing a list of items

B. A screen showing 'Hello World!' text with no buttons

C. A screen with a button labeled 'Click Me'

D. An error message saying 'No layout found'

Solution

1. Step 1: Understand the Empty Activity template

   This template creates a simple app with minimal UI: a single TextView displaying 'Hello World!' by default.

2. Step 2: Run the app to see the default UI

   When you run the app, it shows 'Hello World!' text on screen with no buttons.

3. Final Answer:

   A screen showing 'Hello World!' text with no buttons -> Option B

4. Quick Check:

   Empty Activity default UI = 'Hello World!' screen [OK]

Hint: Empty Activity shows 'Hello World!' text initially [OK]

Common Mistakes:

• Expecting buttons or lists by default
• Thinking the app shows a list automatically
• Confusing error messages with default UI

4. You created a new Android project but the app crashes on launch with an 'ActivityNotFoundException'. What is the most likely cause?

medium

A. You forgot to select Kotlin as the language during project creation

B. You did not connect a physical device

C. You did not set a launcher activity in the manifest

D. You used an unsupported Android Studio version

Solution

1. Step 1: Understand the error meaning

   'ActivityNotFoundException' often means the app can't find the starting point (launcher activity).

2. Step 2: Check AndroidManifest.xml for launcher activity

   If no launcher activity is set, the app crashes because it doesn't know which screen to show first.

3. Final Answer:

   You did not set a launcher activity in the manifest -> Option C

4. Quick Check:

   Missing launcher activity = crash [OK]

Hint: Always set launcher activity in manifest to avoid launch crashes [OK]

Common Mistakes:

• Assuming language choice causes this error
• Blaming Android Studio version without checking manifest
• Thinking device connection causes activity errors

5. You want to create a new Android project that uses Kotlin and includes a basic UI with a button and text. Which template should you select during project creation?

hard

A. Basic Activity

B. Empty Activity

C. No Activity

D. Fullscreen Activity

Solution

1. Step 1: Review available templates

   Empty Activity gives a 'Hello World!' screen; Basic Activity includes a button (FAB) and text by default.

2. Step 2: Choose Basic Activity for UI elements

   Basic Activity template sets up a screen with a button and text, ready for interaction.

3. Final Answer:

   Basic Activity -> Option A

4. Quick Check:

   UI with button = Basic Activity [OK]

Hint: Pick Basic Activity for ready-made button and text UI [OK]

Common Mistakes:

• Choosing Empty Activity expecting UI elements
• Selecting No Activity which has no UI
• Using Fullscreen Activity which is for immersive apps