Mobile Application Development Lab Viva Questions (VTU)

Mobile application development is a booming field with immense opportunities, and engineering students, especially those under the Visvesvaraya Technological University (VTU), often undergo rigorous training in this subject. As part of their assessment, students must appear for viva exams in mobile application development labs. These viva sessions assess not only their theoretical understanding but also their practical proficiency in developing mobile apps. This article will explore various potential questions that could be asked during such viva sessions.

Basic Concepts of Mobile Application Development

1. What is mobile application development? Mobile application development refers to the process of creating software applications that run on mobile devices like smartphones or tablets. The applications can either be pre-installed on the device during manufacturing or delivered as web applications using server-side or client-side processing.

2. Explain the difference between native, hybrid, and web mobile applications.

   • Native applications are built specifically for a particular operating system (OS), like Android or iOS, using programming languages like Swift, Kotlin, or Java.
   • Hybrid applications use web technologies like HTML, CSS, and JavaScript but are wrapped in native containers to function across different platforms.
   • Web applications are responsive websites that can function as applications when viewed on mobile devices.

3. What are the main components of Android applications? Android applications are made up of four key components: Activities, Services, Broadcast Receivers, and Content Providers. Each of these components has a specific role in the application’s functionality.

4. What are the key differences between Android and iOS development? While both platforms serve as operating systems for mobile devices, the development process differs significantly. Android apps are primarily written in Kotlin or Java, while iOS apps are written in Swift or Objective-C. The development environment for Android is Android Studio, while iOS developers use Xcode. Android has a larger market share, but iOS tends to generate more revenue per app.

Android-Specific Questions

1. What is an Activity in Android? An Activity in Android represents a single screen with a user interface. It is an essential component of an Android application and interacts with the user by facilitating actions like clicking buttons or entering text.

2. Explain the lifecycle of an Activity in Android. The Android Activity lifecycle consists of several stages, such as onCreate(), onStart(), onResume(), onPause(), onStop(), onDestroy(), and onRestart(). Each method plays a crucial role in the lifecycle, and it is essential to understand their sequence and purpose.

3. What is the difference between implicit and explicit intents in Android?

   • Implicit Intents do not specify the component to be invoked. Instead, they declare a general action to be performed, which allows the system to determine the best component to handle the intent.
   • Explicit Intents specifically target a particular component (like another Activity or Service) within the app or another app.

4. What is the purpose of the AndroidManifest.xml file? The AndroidManifest.xml file is a crucial part of every Android application. It contains essential information such as the app’s package name, components (Activities, Services, etc.), permissions required by the app, and any other metadata.

iOS-Specific Questions

1. What is the main design pattern used in iOS development? The Model-View-Controller (MVC) design pattern is predominantly used in iOS development. It helps in separating concerns and makes the codebase more modular and easier to maintain.

2. Explain the concept of Auto Layout in iOS. Auto Layout is a powerful layout engine in iOS that helps developers create user interfaces that adapt to different screen sizes and orientations. It uses constraints to specify the relationships between UI elements.

3. What is a delegate in iOS? A delegate is a design pattern in iOS that allows one object to send messages or notifications to another object when certain events occur. It is commonly used in classes like UITableView and UICollectionView.

Cross-Platform Development Questions

1. What are some popular cross-platform frameworks? Some of the most popular cross-platform development frameworks are Flutter, React Native, and Xamarin. These frameworks allow developers to write code once and deploy it across multiple platforms, such as Android and iOS.

2. Explain the pros and cons of using Flutter for mobile application development.

• Pros: Flutter offers fast development cycles with hot reload, excellent UI customization, and supports both Android and iOS platforms with a single codebase.
• Cons: The framework has a steep learning curve, large app size, and might experience performance issues in complex applications.

1. How does React Native work? React Native allows developers to write native applications using JavaScript and React. It bridges the gap between web and mobile development by offering reusable components that can be compiled to native code.

Practical Questions Related to Lab Work

1. How do you debug an Android app using Android Studio? Debugging in Android Studio involves using tools like the Logcat, Breakpoints, and the Debugger. Logcat shows real-time logs from the app, while breakpoints allow you to pause the app at specific lines of code to inspect variables and the state of the app.

2. What are the steps to deploy an iOS app to a real device? To deploy an iOS app to a real device, you need to:

3. Register the device in your Apple Developer account.

4. Create a provisioning profile.

5. Connect your device to Xcode and select it as the deployment target.

6. Run the app on the device.

7. How do you use Android’s Room Database? The Room Database is part of the Android Jetpack libraries. It provides an abstraction layer over SQLite to allow for more robust database access while harnessing the full power of SQLite.

8. What are the common performance optimization techniques in mobile app development? Performance optimization in mobile apps includes:

• Reducing the memory footprint by using efficient data structures and minimizing resource-heavy operations.
• Optimizing network requests and caching data to minimize latency.
• Offloading heavy processing tasks to background threads.

Advanced Questions

1. How do you handle memory leaks in Android? Memory leaks in Android can be managed by using proper memory management practices such as releasing resources when they are no longer needed, avoiding static references to Context, and utilizing tools like Android Profiler to monitor memory usage.

2. What is the significance of Gradle in Android development? Gradle is the build system used in Android development. It helps in compiling, packaging, and deploying Android applications. Gradle is highly flexible and can be customized through the use of plugins.

3. What is SwiftUI, and how does it differ from UIKit? SwiftUI is Apple’s declarative UI framework introduced in iOS 13, which allows developers to build UIs with less code. Unlike UIKit, which is imperative, SwiftUI automatically updates the UI as the state of the app changes, offering a more modern approach to UI development.

4. How do you implement push notifications in an iOS app? Push notifications in iOS require:

• Setting up the Apple Push Notification service (APNs).
• Configuring your app to register for notifications.
• Implementing the necessary code to handle notifications when they are received.

Security and Ethical Questions

1. How do you ensure the security of mobile applications? Ensuring security in mobile applications involves encrypting sensitive data, following secure coding practices, using HTTPS for network communications, and validating user input to prevent attacks like SQL injection and cross-site scripting (XSS).

2. What are the best practices for data storage in mobile apps?

• Avoid storing sensitive data in plaintext, and instead, use encrypted storage solutions.
• For Android, use SharedPreferences or Room Database for small amounts of data, and for iOS, use the Keychain for secure storage.

1. How do you ensure ethical use of user data in your mobile apps? Ensuring ethical use of user data involves following data protection laws like GDPR and CCPA, obtaining user consent before collecting data, and offering transparency regarding how data is used and shared.

Conclusion

These are some of the key questions that could be asked in a VTU mobile application development lab viva. Having a clear understanding of these concepts is crucial for success in both viva exams and real-world application development. Continuous learning and hands-on practice are essential in keeping up with the evolving landscape of mobile development technologies.