Core Flutter framework primitives.

The features defined in this library are the lowest-level utility classes and functions used by all the other layers of the Flutter framework.

Constants

checked → _Checked

Used to annotate a parameter of an instance method that overrides another method.

const _Checked()
kMaxUnsignedSMI → int

The largest SMI value.

0x3FFFFFFFFFFFFFFF
mustCallSuper → _MustCallSuper

Used to annotate an instance method m. Indicates that every invocation of a method that overrides m must also invoke m. In addition, every method that overrides m is implicitly annotated with this same annotation.

const _MustCallSuper()
optionalTypeArgs → _OptionalTypeArgs

Used to annotate a class declaration C. Indicates that any type arguments declared on C are to be treated as optional. Tools such as the analyzer and linter can use this information to suppress warnings that would otherwise require type arguments to be provided for instances of C.

const _OptionalTypeArgs()
protected → _Protected

Used to annotate an instance member (method, getter, setter, operator, or field) m in a class C. If the annotation is on a field it applies to the getter, and setter if appropriate, that are induced by the field. Indicates that m should only be invoked from instance methods of C or classes that extend, implement or mix in C, either directly or indirectly. Additionally indicates that m should only be invoked on this, whether explicitly or implicitly.

const _Protected()
required → Required

Used to annotate a named parameter p in a method or function f. Indicates that every invocation of f must include an argument corresponding to p, despite the fact that p would otherwise be an optional parameter.

const Required()

Typedefs

DebugPrintCallback(String message, { int wrapWidth }) → void

Signature for debugPrint implementations.

FlutterExceptionHandler(FlutterErrorDetails details) → void

Signature for FlutterError.onException handler.

InformationCollector(StringBuffer information) → void

Signature for FlutterErrorDetails.informationCollector callback and other callbacks that collect information into a string buffer.

IterableFilter(Iterable<T> input) → Iterable<T>

Signature for callbacks that filter an iterable.

LicenseEntryCollector() → Stream<LicenseEntry>

Signature for callbacks passed to LicenseRegistry.addLicense.

ServiceExtensionCallback(Map<String, String> parameters) → Future<Map<String, dynamic>>

Signature for service extensions.

ValueChanged(T value) → void

Signature for callbacks that report that an underlying value has changed.

ValueGetter() → T

Signature for callbacks that are to report a value on demand.

ValueSetter(T value) → void

Signature for callbacks that report that a value has been set.

VoidCallback() → void

Signature of callbacks that have no arguments and return no data.

Properties

debugPrint → DebugPrintCallback

Prints a message to the console, which you can access using the "flutter" tool's "logs" command ("flutter logs").

read / write
defaultTargetPlatform → TargetPlatform

The TargetPlatform that matches the platform on which the framework is currently executing.

read-only

Functions

debugPrintStack({String label, int maxFrames }) → void

Dump the current stack to the console using debugPrint and FlutterError.defaultStackFilter.

debugPrintSynchronously(String message, { int wrapWidth }) → void

Alternative implementation of debugPrint that does not throttle. Used by tests.

debugPrintThrottled(String message, { int wrapWidth }) → void

Implementation of debugPrint that throttles messages. This avoids dropping messages on platforms that rate-limit their logging (for example, Android).

debugWordWrap(String message, int width, { String wrapIndent: '' }) → Iterable<String>

Wraps the given string at the given width.

Enums

TargetPlatform

The platform that user interaction should adapt to target.

Classes

BindingBase

Base class for mixins that provide singleton services (also known as "bindings").

BitField

A BitField over an enum (or other class whose values implement "index"). Only the first 62 values of the enum can be used as indices.

CachingIterable

A lazy caching version of Iterable.

ChangeNotifier

A class that can be extended or mixed in that provides a change notification API using VoidCallback for notifications.

FlutterErrorDetails

Class for information provided to FlutterExceptionHandler callbacks.

LicenseEntry

A license that covers part of the application's software or assets, to show in an interface such as the LicensePage.

LicenseEntryWithLineBreaks

Variant of LicenseEntry for licenses that separate paragraphs with blank lines and that hard-wrap text within paragraphs. Lines that begin with one or more space characters are also assumed to introduce new paragraphs, unless they start with the same number of spaces as the previous line, in which case it's assumed they are a continuation of an indented paragraph.

LicenseParagraph

A string that represents one paragraph in a LicenseEntry.

LicenseRegistry

A registry for packages to add licenses to, so that they can be displayed together in an interface such as the LicensePage.

Listenable

An object that maintains a list of listeners.

SynchronousFuture

A Future whose then implementation calls the callback immediately.

Exceptions / Errors

FlutterError

Error class used to report Flutter-specific assertion failures and contract violations.