Whether you’re a fresher, intermediate, or senior developer, these Top Android Interview Questions & Answers can help you crack your next interview!
If you’re preparing for your next job interview, this tutorials equips you with essential preparation by addressing a wide range of top interview questions and answers. Kickstart your Android development career with confidence!
So without wasting any time let’s start Android Interview Questions and Answers
Explain the Android Activity Lifecycle
- onCreate()
- onStart()
- onResume()
- onPause()
- onStop()
- onRestart()
- onDestroy()
- onCreate() – App Launch
When you launch the social media app, it initializes all the necessary components: setting up the user interface, loading user data, and preparing for interaction. This is like onCreate(), where the activity is created for the first time.
- onStart() – Home Feed Loading
After the app launches, the home feed starts loading, showing posts from friends and people you follow. This corresponds to onStart(), where the activity becomes visible to the user, and initial data starts appearing on the screen.
- onResume() – Scrolling Through Feed
You start scrolling through your home feed, liking posts, and maybe commenting on some. This is like onResume(), where the activity is in the foreground, and you’re actively interacting with it.
- onPause() – Notification Popup
Suddenly, a notification pops up, indicating a new message or activity. You pause scrolling through the feed to check the notification. This corresponds to onPause(), where your activity is partially obscured by the notification, but it’s still visible in the background.
- onStop() – Switching to Another App
You decide to switch to another app, maybe to reply to a message or check something else. The social media app is still running in the background, but it’s no longer visible. This is similar to onStop(), where the activity is no longer visible to the user, but it’s still alive in memory.
- onRestart() – Returning to the Social Media App
After finishing your task in the other app, you return to the social media app. It resumes from where you left off, refreshing the feed if necessary. This corresponds to onRestart(), where your activity is brought back to the foreground after being stopped.
- onDestroy() – Closing the App
Finally, you decide to close the social media app. You either explicitly close it or navigate away to a different app. The social media app’s resources are released, and it’s removed from memory. This is like onDestroy(), where the activity is being destroyed, either by the system or manually.
What is an Intent?
An Intent in Android is like a message that requests an action from another component of the app or even from a different app altogether. It’s a fundamental part of how different parts of an Android application communicate with each other and with the system.
- Two type of Intent
Implicit Intent
An Implicit Intent is used when you want the system to determine the appropriate component to fulfill an action based on the intent’s description.
Example
Suppose you’re viewing a post in your social media app and you decide to share it. When you tap the “Share” button, the app creates an Implicit Intent with the action “ACTION_SEND”. The system then looks for all the apps capable of handling this action (such as messaging apps, email apps, etc.) installed on the device. It presents the user with a list of options to choose from, allowing them to share the post through their preferred method.
Explicit Intent
An Explicit Intent is used when you specifically target a particular component within your app to perform a certain action.
Example
Suppose within your social media app, you have a feature to view a user’s profile. When the user taps on a profile picture, the app creates an Explicit Intent to open the “UserProfileActivity” component within the app. The Intent explicitly specifies the target component by its class name. This ensures that the user is directed to the intended destination within the app.
What are the core components of an Android app?
Activities,
Services,
Broadcast Receivers,
Content Providers,
and Views.
What is the difference between Activities and Services?
- Activities
Think of activities as the screens or windows in your app that users interact with. Each activity represents a single screen with a user interface (UI) that users can see and interact with.
Activities handle user interactions, such as tapping buttons, entering text, or swiping between screens. They respond to user input and provide feedback through the UI.
- Services
Services are background operations that run independently of user interaction, performing tasks like downloading files or playing music.
What is ADB (Android Debug Bridge)?
ADB, or Android Debug Bridge, is a command-line tool that allows you to communicate with an Android device or emulator from your computer.
- Bridge Between Computer and Android Devic
Think of ADB as a bridge that connects your computer to your Android device or emulator. It enables you to send commands and perform various tasks on your Android device from your computer’s command line or terminal.
- Debugging and Development
ADB is primarily used for debugging and development purposes. It allows developers to install and debug apps, transfer files, access the device’s shell, and view system logs directly from their computer, without needing to interact with the device physically.
- Testing and Troubleshooting
ADB is invaluable for testing and troubleshooting apps during development. It allows developers to install, uninstall, and manage apps, simulate different device configurations, capture screenshots, and record screen videos for testing purposes.
- Customization and Modification
ADB also enables users to customize and modify their Android devices beyond what’s possible through the user interface alone. You can install custom ROMs, modify system settings, and even access hidden features of your device using ADB commands.