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187 行
5.7 KiB

using System;
using Unity.UIWidgets.animation;
using Unity.UIWidgets.foundation;
using Unity.UIWidgets.scheduler;
using Unity.UIWidgets.widgets;
namespace Unity.UIWidgets.material {
public class TabController : ChangeNotifier {
public TabController(
int initialIndex = 0,
int? length = null,
TickerProvider vsync = null) {
D.assert(length != null && length >= 0);
D.assert(initialIndex >= 0 && (length == 0 || initialIndex < length));
D.assert(vsync != null);
this.length = length.Value;
_index = initialIndex;
_previousIndex = initialIndex;
_animationController = length < 2
? null
: new AnimationController(
value: initialIndex,
upperBound: length.Value - 1,
vsync: vsync);
}
public Animation<float> animation {
get { return _animationController?.view ?? Animations.kAlwaysCompleteAnimation; }
}
readonly AnimationController _animationController;
public readonly int length;
void _changeIndex(int value, TimeSpan? duration = null, Curve curve = null) {
D.assert(value >= 0 && (value < length || length == 0));
D.assert(duration == null ? curve == null : true);
D.assert(_indexIsChangingCount >= 0);
if (value == _index || length < 2) {
return;
}
_previousIndex = index;
_index = value;
if (duration != null) {
_indexIsChangingCount++;
notifyListeners();
_animationController.animateTo(
_index, duration: duration, curve: curve).whenCompleteOrCancel(() => {
_indexIsChangingCount--;
notifyListeners();
});
}
else {
_indexIsChangingCount++;
_animationController.setValue(_index);
_indexIsChangingCount--;
notifyListeners();
}
}
public int index {
get { return _index; }
set { _changeIndex(value); }
}
int _index;
public int previousIndex {
get { return _previousIndex; }
}
int _previousIndex;
public bool indexIsChanging {
get { return _indexIsChangingCount != 0; }
}
int _indexIsChangingCount = 0;
public void animateTo(int value, TimeSpan? duration = null, Curve curve = null) {
duration = duration ?? Constants.kTabScrollDuration;
curve = curve ?? Curves.ease;
_changeIndex(value, duration: duration, curve: curve);
}
public float offset {
get { return length > 1 ? _animationController.value - _index : 0.0f; }
set {
D.assert(length > 1);
D.assert(value >= -1.0f && value <= 1.0f);
D.assert(!indexIsChanging);
if (value == offset) {
return;
}
_animationController.setValue(value + _index);
}
}
public override void dispose() {
_animationController?.dispose();
base.dispose();
}
}
class _TabControllerScope : InheritedWidget {
public _TabControllerScope(
Key key = null,
TabController controller = null,
bool? enabled = null,
Widget child = null
) : base(key: key, child: child) {
this.controller = controller;
this.enabled = enabled;
}
public readonly TabController controller;
public readonly bool? enabled;
public override bool updateShouldNotify(InheritedWidget old) {
_TabControllerScope _old = (_TabControllerScope) old;
return enabled != _old.enabled
|| controller != _old.controller;
}
}
public class DefaultTabController : StatefulWidget {
public DefaultTabController(
Key key = null,
int? length = null,
int initialIndex = 0,
Widget child = null
) : base(key: key) {
D.assert(length != null);
D.assert(child != null);
this.length = length;
this.initialIndex = initialIndex;
this.child = child;
}
public readonly int? length;
public readonly int initialIndex;
public readonly Widget child;
public static TabController of(BuildContext context) {
_TabControllerScope scope =
(_TabControllerScope) context.inheritFromWidgetOfExactType(typeof(_TabControllerScope));
return scope?.controller;
}
public override State createState() {
return new _DefaultTabControllerState();
}
}
class _DefaultTabControllerState : SingleTickerProviderStateMixin<DefaultTabController> {
TabController _controller;
public override void initState() {
base.initState();
_controller = new TabController(
vsync: this,
length: widget.length,
initialIndex: widget.initialIndex
);
}
public override void dispose() {
_controller.dispose();
base.dispose();
}
public override Widget build(BuildContext context) {
return new _TabControllerScope(
controller: _controller,
enabled: TickerMode.of(context),
child: widget.child
);
}
}
}