10+ Android Mobile Application Developer Interview Questions and Answers

The interview questions cover a range of topics related to Android development, including Kotlin, Android 11 features, design patterns, and more.

• Sealed classes are used for representing restricted class hierarchies, while enums are used for representing a fixed set of constants.

• Activity Lifecycle and Fragment Lifecycle are important concepts in Android development for managing the state of activities and fragments.

• Serialization in Java is the process of converting an object i...read more

DB connection should be opened in onCreate() and closed in onDestroy() method.

• Open DB connection in onCreate() method.

• Close DB connection in onDestroy() method.

• Avoid opening and closing DB connection frequently.

• Use SQLiteOpenHelper class to manage DB connection.

Data can be passed between activities using Intent and Bundle.

• Create an Intent object in the sending activity

• Add data to the Intent using putExtra() method

• Start the new activity by calling startActivity() with the Intent

• Retrieve the data in the receiving activity using getIntent() and getExtra()

An array is a data structure that stores a collection of elements of the same type. The index of an array is the position of an element within the array.

• Arrays are used to store multiple values in a single variable.

• To find the index of an element in an array, you can use the indexOf() method.

• Example: String[] array = {"apple", "banana", "orange"}; int index = Arrays.asList(array).indexOf("banana");

Higher Order and Lambda Functions in Kotlin

• Higher order functions are functions that take other functions as parameters or return functions

• Lambda functions are anonymous functions that can be used as arguments or return values in higher order functions

• They provide a concise way to write code and enable functional programming in Kotlin

Flutter is an open-source UI software development kit created by Google for building natively compiled applications for mobile, web, and desktop from a single codebase.

• Flutter allows developers to write code once and deploy it on multiple platforms.

• It uses the Dart programming language and provides a rich set of pre-built widgets for creating beautiful and responsive user interfaces.

• Flutter's hot reload feature enables developers to see the changes instantly without restartin...read more

Multi Modular Project structure is an architectural approach that divides an application into multiple modules for better organization and scalability.

• Divide the application into separate modules based on functionality or features.

• Each module should have its own set of code, resources, and dependencies.

• Modules can communicate with each other through defined interfaces or APIs.

• Modularization helps in code reusability, easier maintenance, and faster development.

• Examples of modu...read more

Shared Preference is a way to store key-value pairs in Android applications.

• Used to store small amounts of data locally on the device

• Data persists even after the app is closed

• Can be used to store user preferences, settings, etc.

• Example: Storing user login credentials

Java has two types of exceptions: checked and unchecked.

• Checked exceptions must be handled by the code, or declared in the method signature with the 'throws' keyword.

• Unchecked exceptions do not need to be handled or declared.

• Examples of checked exceptions include IOException and ClassNotFoundException.

• Examples of unchecked exceptions include NullPointerException and ArrayIndexOutOfBoundsException.

A fragment is a modular section of an activity that has its own lifecycle, layout, and behavior.

• Fragments are reusable components that can be used in multiple activities.

• They can be added or removed from an activity dynamically.

• Fragments allow for better organization and reusability of code.

• Examples include a navigation drawer, a list of items, or a settings screen.