11 Essential Android Developer's Interview Questions

1. What is the manifest file and how is it used?
Answer: Every Android app must have this manifest file in its root directory named ‘AndroidManifest.xml’. The file includes critical information about the app, including the Java package name for the application.
Bonus follow up question: What is the first element in the AndroidManifest file, right after the encoding declaration?
Answer: ‘manifest’ Note: The ‘permissions’ element is the next best answer if the developer assumed you meant the first element within the ‘manifest’ structure.
2. Name 4 ways Android allows you to store data?
Answer: Any of the following 5 possible options are acceptable:
1.SharedPreferences
2.Internal Storage
3.External Storage
4.SQLite Database
5.Network connection
3. What items or folders are important in every Android project?
Answer: The developer should name at least 4 of these 6 items below, as these are essential within each Android project:
1. AndroidManifest.xml
2. build.xml
3. bin/
4. src/
5. res/
6. assets/
4. What is ANR?
Answer: ANR stands for “Application Not Responding”. It’s a dialog box that appears when an application doesn’t respond for more than 10 seconds (sometimes it can be less than 10 seconds). The ANR dialog box offers the user the option of either closing the app or waiting for it to finish running.
5. How do you avoid an ANR?
Answer: A follow-up to the previous question, there are a number of possible answers here. What you want to hear is that you want as little work done as possible on the main thread, also known as the “UI thread”. Since that is the core single thread that your application runs on, you would want to keep activities that require more complex computations or network and database connections, for example, on separate worker threads so as not to slow down the main thread.
6. What are containers?
Answer: Containers holds objects and widgets together, depending on which items are needed and in what arrangement they need to be in. Containers may hold labels, fields, buttons, or even child containers, as examples.
7. What did you like better, Ice Cream Sandwich or KitKat?
Answer: These are code names for Android releases, and are well known throughout the Android community. Your developer should be familiar with them. Ice Cream Sandwich was Android version 4.0 (API level 14) released on October 18, 2011. KitKat refers to Android version 4.4 (API level 19), released on October 31, 2013.
This question is really to weed out the beginners who may not be as familiar with the different Android releases and that changes within each. You really want your developer to be in tuned to the Android updates so they know what’s possible, how to best implement what you are asking, and where things are headed in general.
8. What are App Widgets?
Answer: Also referred to simply as Widgets, App Widgets in the Android world are miniature views that are embedded within Android apps and typically display periodic updates. Music players, weather updates, sports scores, and stock price changes are all examples of data that can be displayed in an App Widget.
9. What is AIDL?
Answer: Android Interface Definition Language. It offers to define the client’s interface requirements and moreover a service in order to communicate at same level with the help of inter process communications.
10. What data types does AIDL support?
Answer: AIDL supports charSequence, list, map, string, and all types of native java data types.
11. What information do you need before you begin coding an Android app for a client?
Answer: You want to find out that this person will seek to truly understand what you are trying to accomplish with your app, and the functionality. The following items are good to hear:
• Objective statement or purpose of the app for the app publisher
• Description of the target audience or user demographics
• Any existing apps that it might be similar to
• Wireframes
• Artwork; The best developers will say they require the artwork to be completed before development. This avoids delays, and helps the developer understand the look, feel and branding you are trying to achieve.