Flutter Fundamentals
Flutter is a user-interface toolkit for building mobile, web, and desktop applications from a shared Dart codebase. You compose widgets to describe each screen, while Flutter supplies rendering, input, accessibility, and platform integration.
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Intro
Flutter Fundamentals
Flutter lets you build applications for mobile, web, and desktop from a shared Dart codebase. You describe the interface as a tree of widgets. Flutter turns that description into pixels, handles input, and connects the application to the host platform.
This course gives you a working map of that system. You will understand where Dart, widgets, state, rendering, packages, and platform code fit. You will also see where shared code helps and where a platform still needs dedicated work.
The central model
Flutter is a reactive, declarative user-interface framework. Declarative means you describe the interface that should exist for the current application state. When the state changes, Flutter rebuilds the affected widget descriptions and updates the rendered interface.
A widget is an immutable description of part of the interface. Text, padding, alignment, layout, gestures, themes, and navigation all use widgets. You combine focused widgets into a widget tree instead of configuring one large screen object.
The build method returns part of that tree. Its BuildContext identifies a widget's location in the tree. Flutter uses that location to resolve nearby information such as themes and navigation.
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Sources
- https://flutter.dev/
Supports
- Flutter is a framework and toolkit for building applications with Dart
- Flutter targets mobile, web, and desktop platforms
- https://docs.flutter.dev/learn/pathway
Supports
- Flutter uses the Dart programming language
- The official pathway covers installation, Dart, widget fundamentals, layout, state, networking, navigation, DevTools, and Flutter internals
- https://dart.dev/language
Supports
- Dart programs use a top-level main function as an entry point
- Dart supports variables, control flow, functions, classes, imports, and asynchronous programming
- https://docs.flutter.dev/resources/architectural-overview
Supports
- Flutter is a reactive and declarative user-interface framework
- Widgets are immutable descriptions composed into a hierarchy
- Elements persist across frames and associate widgets with render objects
- Render objects handle layout, painting, hit testing, and accessibility
- The Flutter stack includes a Dart application, framework, engine, embedder, and runner
- Flutter implements its own controls instead of delegating every control to the operating system
- BuildContext identifies a widget location in the element tree
- https://docs.flutter.dev/data-and-backend/state-mgmt/intro
Supports
- Flutter documents several approaches for managing state shared across an application
- State management concerns the structure and flow of changing application data
- https://docs.flutter.dev/ui/navigation
Supports
- Navigator displays routes as a stack
- Router supports more specific deep-linking and browser address-bar requirements
- Current Flutter guidance does not recommend named routes for most applications and points to go_router or Navigator alternatives
- https://docs.flutter.dev/packages-and-plugins/using-packages
Supports
- A Dart package contains a pubspec.yaml file and can contain code, resources, tests, and dependencies
- A plugin package exposes platform functionality to a Flutter application
- Published Flutter-compatible packages are discoverable through pub.dev
- Packages and plugins can support different combinations of Flutter targets
- https://docs.flutter.dev/platform-integration/platform-channels
Supports
- Platform channels pass asynchronous messages between Dart and host-platform code
- Flutter documents host integrations using Kotlin, Java, Swift, Objective-C, C++, and C
- Web platform integration commonly uses Dart and JavaScript interoperability
- Pigeon can generate type-safe platform-specific channel code
- https://docs.flutter.dev/tools/hot-reload
Supports
- Hot reload injects eligible Dart changes in debug mode and rebuilds the widget tree while preserving state
- Hot reload does not rerun main or initState
- Hot restart loses application state, and native-code changes require a full restart
- https://docs.flutter.dev/testing/overview
Supports
- Flutter testing includes unit, widget, and integration tests
- Unit tests cover functions, methods, or classes; widget tests cover widgets; integration tests cover complete applications or large flows
- Official guidance favors many unit and widget tests plus enough integration tests for important use cases
- https://docs.flutter.dev/perf/best-practices
Supports
- Build methods can run frequently and should avoid repetitive expensive work
- Localizing setState limits the subtree that rebuilds
- Const constructors can reduce rebuild work
- Flutter DevTools includes a performance view for measurement
- https://docs.flutter.dev/ui/accessibility
Supports
- Flutter includes framework accessibility support in addition to operating-system support
- Accessibility should be included in application design and release criteria
- https://docs.flutter.dev/app-architecture/guide
Supports
- Flutter architecture guidance separates user-interface and data layers
- The guidance describes views, view models, repositories, services, and an optional domain layer
- The architecture recommendations are adaptable guidelines rather than mandatory rules
- https://docs.flutter.dev/reference/supported-platforms
Supports
- Flutter documents supported and continuously tested operating-system and browser combinations for each release
- https://github.com/Solido/awesome-flutter
Supports
- The fetched Awesome Flutter list includes Riverpod, Bloc, Flame, Patrol, and Melos as ecosystem resources
- https://riverpod.dev/
Supports
- Riverpod documents declarative state, asynchronous loading and error handling, testing support, linting, refactoring, and DevTools integration
- https://bloclibrary.dev/
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- Bloc is a state-management library for Dart with concepts, architecture, testing guidance, tutorials, and sample applications
- https://flame-engine.org/
Supports
- Flame is a game engine built on Flutter for mobile, desktop, and web
- https://patrol.leancode.co/
Supports
- Patrol is an end-to-end Flutter testing framework with native interaction and device-farm support
- https://melos.invertase.dev/
Supports
- Melos manages multi-package Dart projects with coordinated commands, linking, versioning, changelogs, and publishing