Welcome to the Flutter API reference documentation.
Flutter is Google’s mobile UI framework for crafting high-quality native interfaces on iOS and Android in record time. Flutter works with existing code, is used by developers and organizations around the world, and is free and open source.
The API reference herein covers all libraries that are exported by the Flutter SDK.
More Documentation
This site hosts Flutter's API documentation. Other documentation can be found at the following locations:
- flutter.dev (main site)
- Installation
- Codelabs
- Contributing to Flutter
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.
Other 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';
Finding Other Libraries
Flutter has a rich community of packages that have been contributed by the open-source community. You can browse those packages at pub.dev/flutter
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: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:jsannotated JavaScript interop objects in cases where the name to call is not known at runtime. [...]
Core
VM
Web
platform_integration
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_driverto 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
archive
async
boolean_selector
charcode
- charcode
- Defines symbolic names for character code points. [...]
- charcode.ascii.dollar_lowercase
- Declare integer constants for each ASCII character. [...]
- charcode.htmlentity.dollar_lowercase
- Character codes based on HTML 4.01 character entity names. [...]
collection
- collection
- dart.pkg.collection.algorithms
-
Import
collection.dartinstead. - dart.pkg.collection.equality
-
Import
collection.dartinstead. - dart.pkg.collection.iterable_zip
-
Import
collection.dartinstead. - dart.pkg.collection.priority_queue
-
Import
collection.dartinstead. - dart.pkg.collection.wrappers
-
Import
collection.dartinstead.
convert
crypto
file
image
- image
- The image library aims to provide server-side programs the ability to load, manipulate, and save various image file formats.
intl
- date_symbol_data_custom
- 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
- message_format
-
MessageFormatis a "locale aware printf", with plural / gender support. [...] - 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
json_rpc_2
matcher
meta
- meta
- Constants for use in metadata annotations. [...]
- meta_dart2js
- Constants for use in metadata annotations to provide hints to dart2js. [...]
path
petitparser
- petitparser
- This package contains the core library of PetitParser, a dynamic parser combinator framework.
- petitparser.debug
- This package contains some simple debugging tools.
- petitparser.reflection
- This package contains tools to reflect on and transform parsers.
platform
process
pub_semver
quiver
- quiver.async
- quiver.cache
- quiver.check
- A simple set of pre/post-condition checkers based on the Guava Preconditions class in Java. [...]
- quiver.collection
- Collection classes and related utilities.
- quiver.core
- Simple code with broad use cases.
- quiver.iterables
- quiver.pattern
- This library contains utilities for working with RegExps and other Patterns.
- quiver.strings
- quiver.testing.async
- Testing support for dart:async.
- quiver.testing.equality
- Utilities for testing the equality of Dart object
- quiver.testing.runtime
- Testing support related to the Dart runtime.
- quiver.testing.time
- Testing support for dart:core time functionality.
- quiver.time
source_span
stack_trace
stream_channel
string_scanner
sync_http
term_glyph
test_api
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.
web_socket_channel
- web_socket_channel
- web_socket_channel.io
- web_socket_channel.status
- Status codes that are defined in the WebSocket spec. [...]
webdriver
xml
- xml
- Dart XML is a lightweight library for parsing, traversing, querying and building XML documents.
- xml_events
- Dart XML Events is an event based library to asynchronously parse XML documents and to convert them to other representations.