20+ android and Flutter Developer Interview Questions and Answers

Stateful widgets maintain state across rebuilds, while stateless widgets do not and are immutable.

• StatefulWidget: Can change its state during its lifecycle. Example: Checkbox, TextField.

• StatelessWidget: Immutable and does not hold state. Example: Text, Icon.

• Stateful widgets require a createState() method to manage state.

• Stateless widgets are simpler and faster to build since they don't manage state.

To address the ANRS issue, a comprehensive strategy involving collaboration, education, and technology is essential.

• Implement community outreach programs to raise awareness about ANRS.

• Utilize mobile health applications to provide real-time data and support.

• Collaborate with local health organizations to ensure resource availability.

• Conduct regular training sessions for healthcare providers on ANRS management.

• Leverage social media campaigns to educate the public on prevention a...read more

Designing a modular Android app involves clear architecture, component separation, and efficient communication between modules.

• Use a clean architecture approach, separating presentation, domain, and data layers.

• Implement feature modules to encapsulate specific functionalities, e.g., a user profile module.

• Utilize dependency injection frameworks like Dagger or Hilt for managing dependencies between modules.

• Adopt a microservices architecture for backend integration, allowing ind...read more

State management in Flutter is done using various approaches like setState, InheritedWidget, Provider, BLoC, Redux, etc.

• setState is the simplest approach for small apps with few widgets.

• InheritedWidget is used for sharing data across the widget tree.

• Provider is a popular state management solution that uses InheritedWidget internally.

• BLoC (Business Logic Component) separates business logic from UI and uses Streams to manage state.

• Redux is a predictable state container that use...read more

Bloc is a state management library for Flutter that helps manage the flow of data and events.

• Bloc stands for Business Logic Component.

• It helps separate the presentation layer from the business logic.

• Bloc is commonly used with Flutter to handle state management and data flow.

• It uses streams to handle asynchronous data and events.

• Bloc pattern consists of events, states, and a bloc class to handle the business logic.

Stateful widgets maintain state across rebuilds, while stateless widgets do not and rely solely on their constructor parameters.

• Stateful Widget: Holds state that can change during the widget's lifetime, e.g., a form input that updates as the user types.

• Stateless Widget: Does not hold any state; it is immutable and only depends on the parameters passed to it, e.g., a static text label.

• Rebuilds: Stateful widgets can rebuild when their state changes, while stateless widgets rebu...read more

Polymorphism is the ability of an object to take on many forms.

• Polymorphism allows objects of different classes to be treated as if they are of the same class.

• It is achieved through method overriding and method overloading.

• Example: A parent class Animal can have child classes like Dog, Cat, and Cow. All these child classes can have their own implementation of the method 'makeSound', which is overridden from the parent class.

• Polymorphism helps in achieving code reusability and...read more

Code for input swapping in Flutter

• Create two TextEditingControllers to hold the values of the input fields

• Use a temporary variable to swap the values of the controllers

• Update the state of the input fields with the new values

A StreamBuilder is a Flutter widget that builds itself based on the latest snapshot of interaction with a Stream.

• It listens to a Stream and rebuilds its child widget whenever new data is emitted.

• Useful for displaying real-time data, such as chat messages or live updates.

• Example: StreamBuilder<String>( stream: myStream, builder: (context, snapshot) { if (snapshot.connectionState == ConnectionState.waiting) { return CircularProgressIndicator(); } return Text(snapshot.data); }, ...read more

Dart is a programming language used for building mobile, web, and desktop applications. Pattern refers to a reusable solution to a common problem.

• Dart is an object-oriented language developed by Google.

• It is used to build applications for Android, iOS, web, and desktop platforms.

• Dart is known for its fast performance and easy-to-learn syntax.

• Design patterns are reusable solutions to common software design problems.

• They provide a structured approach to solving problems and imp...read more

State management is a crucial aspect of app development to handle and update the state of the application.

• Local State Management: Managing state within a widget using setState() method.

• InheritedWidget: Sharing state across the widget tree using InheritedWidget.

• Provider: A popular state management solution that uses InheritedWidget under the hood.

• Redux: A predictable state container for managing the state of the app.

• Bloc: A state management solution that uses streams and sinks...read more

Stateless refers to a widget in Flutter that does not have any mutable state.

• Stateless widgets are immutable and their properties cannot change once they are initialized.

• They are used for UI components that do not need to update or change based on user interactions.

• Examples include static text labels, icons, and buttons that do not change appearance.

• Stateless widgets are more efficient than stateful widgets as they do not need to manage state changes.

State management techniques are used to manage the state of an application in a predictable and efficient manner.

• Stateful widgets in Flutter can manage their own state internally.

• Provider package in Flutter allows for a simple and efficient way to manage state.

• Redux is a popular state management library for managing state in Android applications.

StatefulWidget is a class in Flutter that can hold state and can be rebuilt multiple times.

• StatefulWidget is used when the UI needs to dynamically change based on user interactions or data changes.

• It consists of two classes - StatefulWidget and State.

• StatefulWidget is immutable, while State is mutable and holds the widget's state.

• setState() method is used to notify Flutter that the widget's state has changed and needs to be rebuilt.

• Example: TextField widget in Flutter is a St...read more

My expected CTC is based on my experience, skills, and the industry standards.

• My expected CTC is in line with the current market rates for Android and Flutter developers.

• I have taken into consideration my years of experience and expertise in the field.

• I am open to negotiation based on the overall compensation package offered by the company.

Tween animation creates smooth transitions between two states by interpolating values over time.

• Tween animation involves defining a start and end state for an animation.

• It uses interpolation to calculate intermediate values, creating smooth motion.

• In Flutter, the 'Tween' class can be used to define animations, such as changing opacity or position.

• Example: A 'Tween<double>' can animate a widget's size from 0 to 100 over a duration.

• Tween animations can be combined with 'Animati...read more

Flutter is a mobile app SDK for building high-performance, high-fidelity, apps for iOS and Android, from a single codebase.

• Flutter is developed by Google and uses Dart programming language.

• It allows for hot reload, which means developers can see the changes they make in real-time.

• Flutter has its own set of customizable widgets and also supports Material Design and Cupertino widgets.

• It has a reactive programming model and supports asynchronous programming.

• Flutter is used by po...read more

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 is used to develop cross-platform applications.

• It uses the Dart programming language.

• Flutter provides a rich set of pre-designed widgets for building user interfaces.

• It allows hot-reloading, enabling developers to see the changes instantly.

• Flutter apps can be built for Android, iOS, web, and desktop pla...read more

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

• Cross-Platform Development: Flutter allows developers to write code once and deploy it on multiple platforms, such as iOS, Android, and web.

• Rich Widgets: Flutter provides a wide range of customizable widgets that adhere to specific design languages, like Material Design and Cupertino.

• Hot Reload: This feature enables developers to see c...read more

Stateful widgets in Flutter have a lifecycle that includes various methods being called at different stages.

• Stateful widgets have methods like initState(), didChangeDependencies(), build(), and dispose() that are called at different points in the widget's lifecycle.

• initState() is called when the widget is inserted into the tree, didChangeDependencies() is called when the widget's dependencies change, build() is called to build the widget's UI, and dispose() is called when the...read more

OOPs (Object-Oriented Programming) is a programming paradigm based on objects and classes to structure software design.

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

• Inheritance: Mechanism where a new class derives properties and behavior from 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., method overriding in...read more

Provider and GetX are state management solutions for Flutter. Provider is more flexible and requires more boilerplate code, while GetX is simpler and more concise.

• Provider requires more boilerplate code compared to GetX

• GetX is simpler and more concise than Provider

• Provider is more flexible and allows for more customization

• GetX provides built-in functionalities like state management, dependency injection, and routing

• GetX is known for its performance and ease of use

Flutter lifecycle consists of various states that a widget goes through during its existence, impacting its behavior and performance.

• Widgets can be in different states: 'created', 'mounted', 'updated', and 'disposed'.

• The 'initState()' method is called when the widget is first created, ideal for initializing data.

• The 'build()' method is called whenever the widget needs to be rendered, responding to state changes.

• The 'dispose()' method is called when the widget is removed from ...read more