Question 1

What is the difference between var and dynamic in Dart?

Accepted Answer

var determines the type at compile time based on the assigned value and remains fixed afterwards, while dynamic allows changing the type at any moment during runtime. Using var when the type is known provides better type safety and optimal performance as the compiler can perform static checks.

Question 2

What is a mixin in Dart?

Accepted Answer

A mixin is a way to reuse code across multiple class hierarchies without using traditional inheritance. Unlike single inheritance which limits to one parent class, mixins allow composing multiple behaviors into a single class using the with keyword. This promotes a more flexible architecture and avoids the problems of multiple inheritance.

Question 3

What is a widget in Flutter?

Accepted Answer

In Flutter, everything is a widget. A widget is an immutable description of part of the user interface. Widgets describe what their view should look like given their current configuration and state. Flutter uses these descriptions to build the element tree that manages the on-screen rendering.

Question 4

Which method is called first when creating a StatefulWidget?

Accepted Answer

The createState() method is the first one called when instantiating a StatefulWidget. It creates the State object associated with the widget. This method is automatically called by the Flutter framework when the widget is inserted into the widget tree for the first time.

Question 5

What is the main purpose of setState in a StatefulWidget?

Accepted Answer

setState notifies the Flutter framework that the widget's internal state has changed and it needs to rebuild the widget. When setState is called, Flutter schedules a rebuild of the widget to reflect the new state values. Without calling setState, changes to state variables would not trigger a visual update.

Question 6

What is the main role of the Provider package in Flutter?

Accepted Answer

Provider is a wrapper around InheritedWidget that simplifies state management in Flutter. It allows propagating data through the widget tree efficiently without manually passing data through each widget. Provider automatically handles the rebuild of widgets that depend on modified data.

Question 7

Which Flutter package is recommended for simple HTTP requests and is maintained by the Dart team?

Accepted Answer

The http package is the official package maintained by the Dart team for making simple HTTP requests. It provides an easy-to-use API for GET, POST, PUT, and DELETE operations, and is perfectly suited for basic use cases without requiring complex configuration.

Question 8

Which method must be called in dispose() to avoid a memory leak with an AnimationController?

Accepted Answer

The AnimationController's dispose() method releases resources associated with the animation controller, including listeners and internal timers. Without this call, the controller continues running in the background even after the widget is destroyed, causing a memory leak and potentially errors if the controller attempts to update a removed widget.

Question 9

What is a Stream in Dart?

Accepted Answer

A Stream is an asynchronous sequence of data that allows receiving values over time, unlike a Future which returns only a single value. Streams are particularly useful for handling user events, real-time data, or continuous data flows like WebSockets.

Question 10

What is the main advantage of Riverpod over Provider for state management in Flutter?

Accepted Answer

Riverpod eliminates the dependency on BuildContext, allowing providers to be created and accessed from anywhere in the application without widget tree constraints. This independence facilitates testing, avoids ProviderNotFoundException errors, and enables better provider composition. Riverpod also offers increased type safety with compile-time error detection rather than runtime errors.

คำถามสัมภาษณ์ Flutter

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สำรวจหัวข้อ Flutter ทั้งหมด

Dart Basics

Dart Language Essentials

Flutter Fundamentals

Widget Lifecycle

Local Storage

Application Lifecycle

Layouts & Constraints

ListView & GridView

Navigation & Routing

Basic State Management

Provider Pattern

Networking & HTTP

JSON Serialization

Local Database

Forms & Validation

Animations

Firebase Integration

Unit Testing

Widget Testing

Build & Deployment

Package Management

Memory & Performance

Streams & RxDart

Advanced State Management

Flutter Design Patterns

Performance Optimization

Platform Channels

Custom Painting

Flutter Application Architecture

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