Complete guide to help you hire Android Developers

Renowned for its openness and customization capabilities, this platform empowers developers to create everything from simple utilities to sophisticated enterprise-level solutions. The introduction of technologies such as Kotlin and Jetpack has further streamlined and enhanced the efficiency of Android development.

Holding a substantial portion of the global mobile operating system market, Android grants access to an extensive and varied user base. This flexibility paves the way for a diverse range of applications, spanning categories like gaming, entertainment, business, and productivity. The Google Play Store further enhances this ecosystem, offering a straightforward platform for app distribution and monetization.

Native Android development shines when the focus is on performance, responsiveness, and an intuitive user experience. It leverages the distinct features and capabilities of the Android platform, making it the choice for applications that aim to provide a seamless and immersive user experience, replete with smooth animations and robust features. Given Android's vast ecosystem and worldwide user base, native development is a strategic choice for a wide array of applications.

Kotlin has breathed new life into Android development, becoming the preferred choice for new projects. Meanwhile, Java maintains its stronghold, especially in established projects, thanks to its depth and comprehensive capabilities.

Android continues to dominate the global mobile operating system market, holding an impressive share. Emerging trends such as the increasing adoption of 5G, the integration of AI and machine learning in mobile apps, and the heightened focus on app security are shaping the future landscape of Android development.

Industries & applications of Android

Android development plays a crucial role in various sectors, including healthcare, education, finance, entertainment, and more. It enables functionalities such as eCommerce, enterprise solutions, social networking, and IoT applications.

Must-have technical skills for Android Developers

When hiring an Android developer, ensure they possess these essential skills:

• Proficiency in Kotlin and Java: Kotlin, officially supported by Google, has become the preferred and recommended language for Android development due to its modern features and improved safety. Java continues to hold significance, especially for maintaining and updating legacy projects.
• Understanding of Android SDK and Android Studio: In-depth knowledge of the SDK and familiarity with Android Studio for efficient app development.
• Familiarity with Android UI design principles and material design guidelines: Ability to create intuitive and aesthetically pleasing user interfaces.
• Knowledge of architectural patterns: Experience with MVVM, MVP, or MVI for robust and maintainable code structure.
• Experience with databases and storage solutions: Proficiency in using SQLite, Room, and other data persistence technologies.
• Understanding of asynchronous programming: Skills in handling asynchronous tasks using Coroutines, LiveData, or RxJava.
• Experience with Jetpack Components: Familiarity with Jetpack libraries such as Navigation, WorkManager, and Data Binding.
• Knowledge of Dependency Injection: Experience with Dagger or Hilt.
• Proficiency in writing unit and UI tests: Experience with testing frameworks like JUnit and Espresso.
• Advanced UI/UX design skills: Beyond basic adherence to Material Design principles, the ability to innovate and create custom UI components and animations that enhance user engagement.

Nice-to-have technical skills for Android Developers

When looking for a way to separate the great from the good developers, here are some telltale signs that you are dealing with an absolute pro. Look out for these skills in their resume:

• Experience with Advanced Networking Libraries: Familiarity with advanced networking libraries like Retrofit, OkHttp, or Volley for efficient data communication and handling. They should have some experience with some of them.
• Proficiency in Kotlin multiplatform: Skills in developing cross-platform code that can be shared across Android, iOS, and web applications.
• Knowledge of custom graphics and animation: Proficiency in creating custom graphics and animations using OpenGL or libraries like Lottie.
• Understanding of Accessibility and Internationalization: Knowledge of best practices for creating apps that are accessible to a wider range of users, including those with disabilities, and ensuring app content can be easily localized for different regions.
• Knowledge of Cloud Services Integration: Experience with cloud platforms like Google Cloud or AWS for enhanced app functionalities like cloud storage, databases, and machine learning.

Interview questions for Android Developers and their expected answers

Here are some questions and answers we suggest asking to evaluate your candidates’ Android knowledge.

1. Question: What is the Android Activity Lifecycle?

Answer: The Activity Lifecycle in Android is a set of callback methods that manage the state of an activity. The lifecycle begins with onCreate(), where the activity is initialized. onStart() makes the activity visible, and onResume() makes it interactive. onPause() is called when the activity is partially obscured, and onStop() when it’s no longer visible. Finally, onDestroy() is called before the activity is destroyed. Understanding the lifecycle is crucial for managing resources and ensuring a smooth user experience.

2. Question: Explain the difference between a Fragment and an Activity.

Answer: An Activity in Android is a single, focused thing a user can do, whereas a Fragment represents a behavior or a portion of the user interface. Fragments are modular and can be combined in a single activity to build a multi-pane UI. They have their own lifecycle but are dependent on the hosting activity's lifecycle. While an Activity can stand alone, Fragments are designed to be reused and nested within Activities, allowing more dynamic and flexible UI designs.

3. Question: How do you handle background tasks in Android?

Answer: For handling background tasks in Android, it's recommended to use modern approaches like Kotlin Coroutines or WorkManager, which offer more robust and efficient task management. While AsyncTask was used historically for short operations, it has been deprecated in favor of these contemporary methods. Services are suitable for long-running tasks without UI, and JobScheduler or WorkManager can be used for the efficient scheduling of tasks.

4. Question: What are Intents in Android?

Answer: Intents in Android are messaging objects used to request an action from another app component. There are two types: explicit intents specify the component to start by its name, and implicit intents declare a general action to be performed, allowing the system to find suitable components. Intents are used for various purposes, such as starting activities services, or broadcasting messages across different components of the system.

5. Question: How do you ensure your app is performant and responsive?

Answer: Ensuring app performance involves profiling the app using Android Profiler to identify and optimize bottlenecks. This includes optimizing layouts, reducing overdraw, managing memory efficiently, and implementing lazy loading. Keeping the main thread free for UI operations and offloading heavy tasks to background threads are essential practices. Data structures should be chosen wisely to reduce time and space complexity.

6. Question: Can you explain the concept of Dependency Injection and its benefits?

Answer: Dependency Injection (DI) is a design pattern in which objects receive their dependencies from external sources rather than creating them internally. It increases modularity and makes the code more testable, maintainable, and scalable. In Android, DI frameworks like Dagger or Hilt are often used to manage dependencies, injecting them where needed, thus decoupling the objects and reducing tight interdependencies.

7. Question: What are some common security practices in Android development?

Answer: In Android development, common security practices include using ProGuard for code obfuscation, implementing SSL/TLS for secure network communications, and using encryption for sensitive data. It’s also crucial to use secure storage mechanisms like SharedPreferences in Encrypted Mode or KeyStore for storing private keys. Additionally, following best practices for user authentication, such as implementing OAuth, and regularly updating libraries and dependencies to patch vulnerabilities are vital for app security.

8. Question: How do you manage the state in an Android application, especially during configuration changes like screen rotation?

Answer: Managing state in Android, particularly during configuration changes like screen rotations, requires an understanding of the activity lifecycle and persistence mechanisms. During configuration changes, activities are destroyed and recreated, which can lead to loss of state. To handle this, developers can use methods like onSaveInstanceState() to save the activity's dynamic state and onRestoreInstanceState() or onCreate() to restore it. For more complex data, ViewModel from the Android Architecture Components is recommended. ViewModel is lifecycle-aware and retains data across configuration changes, ensuring a seamless user experience. For persistent storage, options like Shared Preferences, SQLite databases, or even Room – a higher-level abstraction over SQLite – can be used.

9. Question: Can you explain what RecyclerView is and why it’s preferred over ListView in Android?

Answer: RecyclerView is a more advanced and flexible version of ListView that is used to display large sets of data in a scrollable list. Unlike ListView, RecyclerView is more efficient with memory usage and smoother in handling large data sets. It uses the ViewHolder pattern, which caches views and reuses them, reducing the overhead of creating new views during scrolling. RecyclerView is also highly customizable and supports different types of layouts, such as linear, grid, and staggered grids. It allows for custom animations and decorations for items, making it a go-to choice for complex and dynamic lists.

10. Question: Explain the concept of Broadcast Receivers in Android and provide a use case.

Answer: Broadcast Receivers in Android are components that respond to system-wide broadcast announcements or messages from other applications. They act as a gateway to the outside world for an app, allowing it to listen for and respond to a variety of broadcast messages, such as when the device boots up, when the network changes, or when the battery is low. A common use case is creating a BroadcastReceiver to monitor network changes. By registering for the CONNECTIVITY_CHANGE action, the app can receive notifications whenever the device's network status changes, allowing it to adapt its behavior accordingly, like pausing downloads or updates when the network is unavailable.

Business benefits of Android development

Companies often opt for Android as the platform for their applications due to its vast user base, customization flexibility, and ease of integration with a wide range of devices and ecosystems, providing a broad market reach, tailored user experiences, and diverse integration opportunities.

• Wide reach: Access to a large and diverse user base.
• Flexibility: Open-source nature allows for customization and integration with a variety of hardware and software.
• Monetization options: Multiple avenues for app monetization, including in-app purchases and advertising.

Summary

To summarize, the essential skills and tools a good Android developer should be equipped within their career to be able to build Android-based applications successfully are:

• Programming skills: Proficiency in Kotlin and Java, with a strong understanding of object-oriented programming and SOLID principles.
• Android ecosystem expertise: Knowing Android SDK, Android Studio, and Jetpack components well is important. A good developer should be able to use these tools creatively.
• Design skills: An eye for pixel-perfect design, ensuring the development of aesthetically pleasing and user-friendly interfaces.
• Continuous learning: The Android platform constantly evolves. A good developer stays updated with the latest trends and technologies in Android development.
• Teamwork skills: Experience with collaborative tools and version control systems like Git is essential. A developer should work well in a team setting.
• SOLID Principles: Familiarity with SOLID principles to craft maintainable and robust software architectures.