67 lines
1.4 KiB
Dart
67 lines
1.4 KiB
Dart
import 'package:event_bus/event_bus.dart';
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import 'package:flutter/foundation.dart';
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import 'package:flutter/widgets.dart';
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class HighlightInfo extends ChangeNotifier {
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final EventBus eventBus = EventBus();
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void trackItem<T>(
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T? item, {
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TrackPredicate? predicate,
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Alignment? alignment,
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bool? animate,
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Object? highlightItem,
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}) {
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if (item != null) {
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eventBus.fire(TrackEvent<T>(
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item,
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predicate ?? (_) => true,
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alignment ?? Alignment.center,
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animate ?? true,
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highlightItem,
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));
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}
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}
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Object? _item;
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void set(Object item) {
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if (_item == item) return;
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_item = item;
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notifyListeners();
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}
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Object? clear() {
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if (_item == null) return null;
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final item = _item;
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_item = null;
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notifyListeners();
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return item;
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}
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bool contains(Object item) => _item == item;
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@override
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String toString() => '$runtimeType#${shortHash(this)}{item=$_item}';
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}
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@immutable
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class TrackEvent<T> {
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final T item;
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final TrackPredicate predicate;
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final Alignment alignment;
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final bool animate;
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final Object? highlightItem;
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const TrackEvent(
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this.item,
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this.predicate,
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this.alignment,
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this.animate,
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this.highlightItem,
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);
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}
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// `itemVisibility`: percent of the item tracked already visible in viewport
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// return whether to proceed with tracking
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typedef TrackPredicate = bool Function(double itemVisibility);
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