Flutter

Welcome to the Flutter API reference documentation!

Flutter is Google's SDK for crafting beautiful, fast user experiences for mobile, web, and desktop from a single codebase. Flutter works with existing code, is used by developers and organizations around the world, and is free and open source.

This API reference covers all libraries that are exported by the Flutter SDK.

Importing a Library

Framework Libraries

Libraries in the "Libraries" section below (or in the left navigation) are part of the core Flutter framework and are imported using 'package:flutter/<library>.dart', like so:

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

Dart Libraries

Libraries in the "Dart" section exist in the dart: namespace and are imported using 'dart:<library>', like so:

import 'dart:async';
import 'dart:ui';

Except for 'dart:core', you must import a Dart library before you can use it.

Supporting Libraries

Libraries in other sections are supporting libraries that ship with Flutter. They are organized by package and are imported using 'package:<package>/<library>.dart', like so:

import 'package:flutter_test/flutter_test.dart';
import 'package:file/local.dart';

Packages on pub.dev

Flutter has a rich ecosystem of packages that have been contributed by the Flutter team and the broader open source community to a central repository. Among the thousands of packages, you'll find support for Firebase, Google Fonts, hardware services like Bluetooth and camera, new widgets and animations, and integration with other popular web services. You can browse those packages at pub.dev.

Libraries

animation: The Flutter animation system.
cupertino: Flutter widgets implementing the current iOS design language.
foundation: Core Flutter framework primitives.
gestures: The Flutter gesture recognizers.
material: Flutter widgets implementing Material Design.
painting: The Flutter painting library.
physics: Simple one-dimensional physics simulations, such as springs, friction, and gravity, for use in user interface animations.
rendering: The Flutter rendering tree.
scheduler: The Flutter Scheduler library.
semantics: The Flutter semantics package.
services: Platform services exposed to Flutter apps.
widgets: The Flutter widgets framework.

Dart

dart:ui: Built-in types and core primitives for a Flutter application.
dart:wasm
dart:async: Support for asynchronous programming, with classes such as Future and Stream.
dart:collection: Classes and utilities that supplement the collection support in dart:core.
dart:convert: Encoders and decoders for converting between different data representations, including JSON and UTF-8.
dart:core: Built-in types, collections, and other core functionality for every Dart program.
dart:developer: Interact with developer tools such as the debugger and inspector.
dart:math: Mathematical constants and functions, plus a random number generator.
dart:typed_data: Lists that efficiently handle fixed sized data (for example, unsigned 8 byte integers) and SIMD numeric types.
dart:ffi: Foreign Function Interface for interoperability with the C programming language.
dart:io: File, socket, HTTP, and other I/O support for non-web applications.
dart:isolate: Concurrent programming using isolates: independent workers that are similar to threads but don't share memory, communicating only via messages.
dart:html: HTML elements and other resources for web-based applications that need to interact with the browser and the DOM (Document Object Model).
dart:js: Low-level support for interoperating with JavaScript.
dart:js_util: Utility methods to manipulate package:js annotated JavaScript interop objects in cases where the name to call is not known at runtime.

platform_integration

Android: Flutter platform integration APIs for Android.
iOS: Flutter platform integration APIs for iOS.

flutter_test

flutter_test: Testing library for flutter, built on top of package:test.

flutter_driver

flutter_driver: Provides API to test Flutter applications that run on real devices and emulators.
flutter_driver_extension: This library provides a Dart VM service extension that is required for tests that use package:flutter_driver to drive applications from a separate process, similar to Selenium (web), Espresso (Android) and UI Automation (iOS).

flutter_localizations

flutter_localizations: Localizations for the Flutter library.

flutter_web_plugins

flutter_web_plugins: The platform channels and plugin registry implementations for the web implementations of Flutter plugins.
url_strategy

async

async: Utilities that expand on the asynchronous features of the dart:async library.

boolean_selector

boolean_selector

characters

characters: String operations based on characters (Unicode grapheme clusters).

clock

clock

collection

collection
dart.pkg.collection.algorithms: Import collection.dart instead.
dart.pkg.collection.equality: Import collection.dart instead.
dart.pkg.collection.iterable_zip: Import collection.dart instead.
dart.pkg.collection.priority_queue: Import collection.dart instead.
dart.pkg.collection.wrappers: Import collection.dart instead.

crypto

crypto

fake_async

fake_async

file

chroot: A file system that provides a view into another FileSystem via a path.
file: Core interfaces containing the abstract FileSystem interface definition and all associated types used by FileSystem.
local: A local file system implementation. This relies on the use of dart:io and is thus not suitable for use in the browser.
memory: An implementation of FileSystem that exists entirely in memory with an internal representation loosely based on the Filesystem Hierarchy Standard.

integration_test

_callback_io
_callback_web
_extension_io
_extension_web
common
integration_test
integration_test_driver
integration_test_driver_extended

intl

date_symbol_data_custom: API to allow setting Date/Time formatting in a custom way.
date_symbol_data_file: This file should be imported, along with date_format.dart in order to read locale data from files in the file system.
date_symbol_data_http_request: This file should be imported, along with date_format.dart in order to read locale data via http requests to a web server..
date_symbol_data_local: Date/time formatting symbols for all locales.
date_symbols
date_time_patterns: Date/time formatting symbols for a large subset of locales.
intl: This library provides internationalization and localization. This includes message formatting and replacement, date and number formatting and parsing, and utilities for working with Bidirectional text.
intl_standalone: This provides facilities for Internationalization that are only available when running standalone. You should import only one of this or intl_browser.dart. Right now the only thing provided here is finding the operating system locale.
locale: This library provides access to the Locale class.
message_format: MessageFormat prepares strings for display to users, with optional arguments (variables/placeholders). The arguments can occur in any order, which is necessary for translation into languages with different grammars. It supports syntax to represent plurals and select options.
message_lookup_by_library: Message/plural format library with locale support. This can have different implementations based on the mechanism for finding the localized versions of messages. This version expects them to be in a library named e.g. 'messages_en_US'. The prefix is set in the "initializeMessages" call, which must be made for a locale before any lookups can be done.
number_symbol_data: Date/time formatting symbols for all locales.
number_symbols

matcher

matcher: Support for specifying test expectations, such as for unit tests.

material_color_utilities

blend
cam16
cam_solver
color_utils
core_palette
hct
material_color_utilities
math_utils
point_provider
point_provider_lab
quantizer
quantizer_celebi
quantizer_map
quantizer_wsmeans
quantizer_wu
scheme
score
string_utils
tonal_palette
viewing_conditions

path

path: A comprehensive, cross-platform path manipulation library.

platform

platform: Core interfaces & classes.

process

process

source_span

source_span

stack_trace

stack_trace

stream_channel

isolate_channel
stream_channel

string_scanner

string_scanner: A library for parsing strings using a sequence of patterns.

sync_http

sync.http

term_glyph

term_glyph

test_api

expect
hooks
test_api
test_api.backend
test_api.fake
test_api.scaffolding

typed_data

typed_data: Utilities and functionality related to the "dart:typed_data" library.
typed_data.typed_buffers: Growable typed-data lists.

vector_math

hash
vector_math: A library containing different type of vector operations for use in games, simulations, or rendering.
vector_math_64: A library containing different type of vector operations for use in games, simulations, or rendering.
vector_math_geometry: A library containing geometry generators (like CubeGenerator, SphereGenerator and CylinderGenerator) and filters (BarycentricFilter, ColorFilter and InvertFilter).
vector_math_lists: A library for working with lists of vectors in a memory efficient way.
vector_math_operations: A library containing matrix operations (Matrix44Operations) that can be performed on Float32List instances and SIMD optimized operations (Matrix44SIMDOperations) that can be performed on Float32x4List instances.

vm_service

utils
vm_service
vm_service_io

webdriver

webdriver.core
webdriver.core
webdriver.html
webdriver.io
webdriver.io
webdriver.support.async
webdriver.support.firefox_profile
webdriver.support.stdio_stepper
webdriver.sync_core
webdriver.sync_io

More Documentation