Flutter is an open-source UI software development kit created by Google. It is used to develop applications for Android, iOS, Linux, Mac, Windows, Google Fuchsia, and the web from a single codebase.
The major components of flutter include:
• Dart platform
• Flutter engine
• Foundation library
• Design-specific widgets
• Flutter devTools
Flutter apps are written in the Dart language and make use of many of the language’s more advanced features. On Windows, macOS, and Linux flutter runs in the Dart virtual machine, which features a just-in-time execution engine. While writing and dubbing an app, flutter used Just In Time compilation, allowing for “hot reload”, with which modifications to source files can be injected into a running application. Flutter extends this with support for stateful hot reload, where in most cases changes to sources code are reflected immediately in the running app without requiring a restart or any loss of state.
Flutter’s engine, written primarily in C++, provides low-level rendering support using Google’s Skia graphics library. Additionally, it interfaces with platform-specific SDKs such as those provided by Android and iOS. The flutter engine is a portable runtime for hosting Flutter applications. It implementation flutter’s core libraries, including animation and graphics, file and network I/O, accessibility support, plugin architecture, and a Dart runtime and compile toolchain. Most developers interact with Flutter via the Flutter Framework, which provides a reactive framework and a set of platform, layout, and foundation widgets.
The foundation library, written in Dart, provides basic classes and functions that are used to construct applications using Flutter, such as APIs to communicate with the engine.
The Flutter framework contains two sets of widgets that conform to specific design languages: Material Design widgets implement Google’s design language of the same name, and Cupertino widgets implement Apple’s iOS Human interface guidelines.