20+ Mobile App Developer Interview Questions and Answers

A teraflop is a unit of computing speed equal to one trillion floating-point operations per second (FLOPS).

• A teraflop is a measure of a computer's processing speed and is commonly used to compare the performance of different processors.

• A 2.8 GHz processor can perform 2.8 billion cycles per second.

• To calculate the number of floating-point calculations, we need to know the number of floating-point operations per cycle (FLOP/cycle) of the processor.

• Without the FLOP/cycle value, ...read more

Memory leaks occur when a program fails to release memory it no longer needs. Async/await is used to manage asynchronous operations.

• Memory leaks happen when a program fails to release memory it no longer needs

• Widgets are graphical elements used in mobile app development, such as buttons and text boxes

• Async/await is used to manage asynchronous operations and prevent blocking the main thread

• Augmented Reality is a technology that overlays digital information onto the real world

Work Manager is an Android API that schedules deferrable, asynchronous tasks that are expected to run even if the app exits or the device restarts.

• Work Manager is useful for executing background tasks that are not time-sensitive.

• It provides a flexible API to schedule tasks based on various constraints like network availability, battery status, and charging state.

• It can also handle tasks that need to be executed immediately or at a specific time.

• Work Manager can be used to per...read more

Android platform consists of four main components: activities, services, broadcast receivers, and content providers.

• Activities: user interface components that represent a single screen with a user interface

• Services: background components that perform long-running operations

• Broadcast receivers: components that respond to system-wide broadcast announcements

• Content providers: components that manage a shared set of app data

Real-time operating systems (RTOS) are designed to run applications with strict timing requirements.

• RTOS are optimized for deterministic and predictable response times.

• They prioritize tasks based on their urgency and importance.

• Examples of RTOS include FreeRTOS, VxWorks, and QNX.

• RTOS are commonly used in industries such as aerospace, automotive, and industrial automation.

A headless client in Android can be created using a Service component.

• Create a Service component that runs in the background without a UI

• Use the onStartCommand() method to start the service

• Use the onBind() method to bind the service to a client

• Use the onDestroy() method to stop the service

• Example: A music player app that continues playing music even when the app is closed

Supercomputers are much more powerful than regular computers, with faster processing speeds and larger memory capacities.

• Supercomputers are designed for high-performance computing and can perform complex calculations and simulations at a much faster rate than regular computers.

• Supercomputers have a larger number of processors and can handle massive amounts of data simultaneously.

• Supercomputers are often used in scientific research, weather forecasting, and simulations of nucl...read more

I am interested in Artificial Intelligence and Machine Learning.

• I have experience in developing chatbots using NLP and ML algorithms.

• I am interested in exploring computer vision and image recognition.

• I have worked with TensorFlow and Keras for developing ML models.

• I am also interested in exploring the potential of AI in healthcare and medical diagnosis.

The number of types of data sent in API varies depending on the API and its purpose.

• The number of data types can range from one to many.

• Examples of data types include text, numbers, images, and files.

• API documentation should specify the types of data that can be sent and received.

Json data can be accessed using APIs or libraries in programming languages like JavaScript, Python, and Java.

• Use fetch() method in JavaScript to retrieve Json data from an API endpoint

• Use json.loads() method in Python to convert Json data into a Python dictionary

• Use Gson library in Java to parse Json data into Java objects

• Json data can also be accessed using third-party libraries like jQuery and Axios

Android Architecture is a layered software stack consisting of four main layers.

• The four layers are: Linux Kernel, Libraries, Runtime, and Application Framework

• Linux Kernel provides low-level hardware abstraction and security

• Libraries provide a set of pre-built functions for developers to use

• Runtime includes the Dalvik Virtual Machine and core libraries

• Application Framework provides a set of high-level services for app development

Exception handling is the process of responding to the occurrence of exceptions during program execution.

• Use try-catch blocks to handle exceptions

• Catch specific exceptions to handle them differently

• Use finally block to execute code regardless of exception

• Throw custom exceptions to handle specific scenarios

Flutter is an open-source mobile application development framework created by Google.

• Flutter uses the Dart programming language.

• It allows for fast development and hot reloading.

• Flutter provides a rich set of pre-built widgets for building beautiful UIs.

• It supports both Android and iOS platforms.

• Flutter is used by companies like Alibaba, Google Ads, and Reflectly.

To access a database, you need to establish a connection and use SQL queries to retrieve or modify data.

• Choose a database management system (DBMS) and install it on your device or server

• Create a database and tables with appropriate fields

• Establish a connection to the database using a programming language or tool

• Use SQL queries to retrieve or modify data

• Close the connection when finished

Kotlin is a statically typed programming language that runs on the Java Virtual Machine and can be used for Android app development.

• Kotlin is interoperable with Java, meaning that developers can use both languages in the same project

• Kotlin has null safety features, which help prevent null pointer exceptions

• Kotlin has extension functions, which allow developers to add functionality to existing classes without having to inherit from them

• Kotlin has data classes, which are classe...read more

Object Oriented Programming (OOP) is a programming paradigm based on the concept of objects, which can contain data and methods.

• Encapsulation: Bundling data and methods that operate on the data within one unit (e.g., a class).

• Inheritance: Mechanism to create a new class using properties and methods of an existing class (e.g., a 'Dog' class inheriting from an 'Animal' class).

• Polymorphism: Ability to present the same interface for different underlying data types (e.g., a functi...read more

Java is a high-level programming language used for developing desktop, web, and mobile applications.

• Java is an object-oriented language

• It is platform-independent

• Java code is compiled into bytecode

• Java Virtual Machine (JVM) executes the bytecode

• Java is used for developing Android apps

Android life cycle refers to the stages a mobile app goes through from creation to termination.

• There are four stages in the Android life cycle: onCreate(), onStart(), onResume(), and onDestroy().

• onCreate() is called when the app is first created.

• onStart() is called when the app becomes visible to the user.

• onResume() is called when the app is in the foreground and the user is interacting with it.

• onDestroy() is called when the app is terminated or destroyed by the system.

• The li...read more

Java, Kotlin, and Dart are all popular programming languages for mobile app development.

• Java is the most widely used language for Android app development.

• Kotlin is a newer language that is gaining popularity due to its concise syntax and interoperability with Java.

• Dart is the language used for developing apps with Flutter, a popular cross-platform framework.

• Each language has its own strengths and weaknesses, and the choice depends on the specific requirements of the project.

Intents are actions that can be performed in an app. There are two types of intents: explicit and implicit.

• Explicit intents are used to start a specific component within the app, such as opening a new activity or service.

• Implicit intents are used to request an action from another app, such as opening a web page or sending an email.

• Intents can also have data attached to them, such as a URI or extra information.

• Examples of intents include opening a camera app to take a photo, s...read more