Round 1: Android Core Concepts
The first round was crucial, focusing on Android core concepts. The interviewer began with his introduction, which helped ease my initial nervousness. As it was my first interview with a product-based company, I felt quite anxious. However, his friendly approach and initial questions about my background helped me relax.
Project Discussion:
The discussion kicked off with a deep dive into the projects I had worked on, as mentioned in my resume. I described a project where I encountered a data type mismatch error in Retrofit. The interviewer probed further:
How did you identify the error?
What was the reason for the error?
How did you debug it?
I explained the debugging process, mentioning my use of Postman, which led to more questions about how I used the tool. This highlighted the importance of not only understanding the tools we use but also being able to explain our problem-solving process in detail.
App Architecture:
Next, we moved to app architecture, particularly MVVM, which I had implemented in my projects. The questions became progressively more challenging:
Practical implementation of MVVM
Detailed explanation of ViewModel and its lifecycle
One particularly challenging scenario was:
Scenario Question: If I create Activity A and a corresponding ViewModelA to hold its data, and I instantiate the ViewModel using ViewModelProviders in onCreate, then start a new instance of Activity A on top of the existing Activity A, will the ViewModel be created again for the new instance? Please explain.
Follow-up Question: What happens to the ViewModel when we navigate back from the new instance of Activity A to the original instance of Activity A?
I answered that the ViewModel is tied to the lifecycle of the Activity or Fragment, and it will be created when the Activity or Fragment is created and cleared when they are destroyed. While my answer was correct, my lack of confidence was a significant drawback. It underscored the need for thorough preparation and self-assurance.
LiveData and ViewModel:
We then discussed the practical implementation of LiveData and ViewModel. He asked about passing data between fragments and activities, followed by scenario-based questions about configuration changes (e.g., screen orientation changes). He inquired whether a bundle with data would preserve the data during such changes and explored other ways of passing data.
Intent Handling:
Question: When we send an intent with a specific type, like sharing an image, how does the Android system or other apps know which app should handle the specific intent?
This question delved into the intricacies of Android’s intent system, highlighting the need to understand the underlying mechanisms of the platform.
Coroutines:
We wrapped up with a discussion on coroutines. The interviewer asked for practical implementations and followed up with deeper questions based on my responses. This part of the interview reiterated the importance of practical knowledge over theoretical understanding.
