blob: 9370bf7167ef35bf07a7a7d68cfc159a5bba2439 [file] [log] [blame]
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:ui' as ui show AccessibilityFeatures;
import 'package:flutter/foundation.dart';
import 'debug.dart';
export 'dart:ui' show AccessibilityFeatures;
/// The glue between the semantics layer and the Flutter engine.
// TODO(jonahwilliams): move the remaining semantic related bindings here.
mixin SemanticsBinding on BindingBase {
/// The current [SemanticsBinding], if one has been created.
static SemanticsBinding get instance => _instance;
static SemanticsBinding _instance;
@override
void initInstances() {
super.initInstances();
_instance = this;
_accessibilityFeatures = window.accessibilityFeatures;
}
/// Called when the platform accessibility features change.
///
/// See [Window.onAccessibilityFeaturesChanged].
@protected
void handleAccessibilityFeaturesChanged() {
_accessibilityFeatures = window.accessibilityFeatures;
}
/// The currently active set of [AccessibilityFeatures].
///
/// This is initialized the first time [runApp] is called and updated whenever
/// a flag is changed.
///
/// To listen to changes to accessibility features, create a
/// [WidgetsBindingObserver] and listen to [didChangeAccessibilityFeatures].
ui.AccessibilityFeatures get accessibilityFeatures => _accessibilityFeatures;
ui.AccessibilityFeatures _accessibilityFeatures;
/// The platform is requesting that animations be disabled or simplified.
///
/// This setting can be overridden for testing or debugging by setting
/// [debugSemanticsDisableAnimations].
bool get disableAnimations {
bool value = _accessibilityFeatures.disableAnimations;
assert(() {
if (debugSemanticsDisableAnimations != null)
value = debugSemanticsDisableAnimations;
return true;
}());
return value;
}
}