Project structure (app, gradle, manifests) in Android Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Identify the role of the app module in an Android project

In an Android project, what is the primary purpose of the app module folder?

A It contains the source code, resources, and configuration files for the Android application.

B It manages the build scripts and dependencies for the entire project including all modules.

C It holds only the manifest files for all modules in the project.

D It stores the global Gradle wrapper files used by all modules.

💡 Hint

Think about where you write your Kotlin code and place your images or layouts.

The app module is the main module where you write your app's Kotlin code, add resources like layouts and images, and configure the AndroidManifest.xml specific to your app.

❓ ui_behavior

intermediate

What happens if you change the applicationId in build.gradle?

If you change the applicationId in the app/build.gradle file, what is the effect when you run the app?

A The app's UI layout will change automatically to match the new ID.

B The app updates the existing app on the device regardless of the ID.

C The app will fail to build due to a missing manifest file.

D The app installs as a new, separate app on the device with the new ID.

💡 Hint

Think about how Android identifies apps uniquely on a device.

The applicationId uniquely identifies your app on the device. Changing it causes Android to treat it as a different app, so it installs separately.

❓ lifecycle

advanced

Order of manifest merging in Android projects

When building an Android app, the final AndroidManifest.xml is created by merging multiple manifests. Which is the correct order of priority from highest to lowest during this merge?

A 4, 2, 1, 3

B 1, 4, 2, 3

C 4, 1, 2, 3

D 3, 2, 1, 4

💡 Hint

Build variants and flavors can override app module settings.

The manifest merging prioritizes build variants/flavors first, then the app module manifest, followed by library manifests, and finally the Android SDK manifest.

📝 Syntax

advanced

Identify the correct Gradle dependency syntax

Which of the following is the correct way to add the Kotlin standard library dependency in the app/build.gradle file?

A implementation "org.jetbrains.kotlin:kotlin-stdlib:1.8.0"

B implementation 'org.jetbrains.kotlin:kotlin-stdlib:1.8.0'

C compile 'org.jetbrains.kotlin:kotlin-stdlib:1.8.0'

D compile "org.jetbrains.kotlin:kotlin-stdlib:1.8.0"

💡 Hint

Modern Gradle uses 'implementation' with single quotes for dependencies.

The correct syntax uses 'implementation' with single quotes. 'compile' is deprecated and double quotes are allowed but single quotes are preferred.

🔧 Debug

expert

Why does the app crash on startup after manifest change?

You changed the android:name attribute in the application tag of your AndroidManifest.xml to a custom Application class but the app crashes immediately on launch. What is the most likely cause?

A The custom Application class does not extend <code>android.app.Application</code>.

B The custom Application class is not declared in the <code>build.gradle</code> file.

C The custom Application class is missing a default constructor.

D The <code>android:name</code> attribute must be set in the <code>activity</code> tag, not <code>application</code>.

💡 Hint

The system expects a specific base class for the Application attribute.

The custom Application class must extend android.app.Application. If it does not, the app will crash because the system cannot instantiate it properly.