54 lines
1.2 KiB
Dart
54 lines
1.2 KiB
Dart
import 'package:flutter/foundation.dart';
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class Selection<T> extends ChangeNotifier {
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bool _isSelecting = false;
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bool get isSelecting => _isSelecting;
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final Set<T> _selectedItems = {};
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Set<T> get selectedItems => _selectedItems;
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void browse() {
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if (!_isSelecting) return;
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_isSelecting = false;
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notifyListeners();
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}
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void select() {
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if (_isSelecting) return;
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// clear selection on `select`, not on `browse`, so that
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// the selection count is stable when transitioning to browse
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clearSelection();
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_isSelecting = true;
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notifyListeners();
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}
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bool isSelected(Iterable<T> items) => items.every(selectedItems.contains);
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void addToSelection(Iterable<T> items) {
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if (items.isEmpty) return;
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select();
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_selectedItems.addAll(items);
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notifyListeners();
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}
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void removeFromSelection(Iterable<T> items) {
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if (items.isEmpty) return;
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_selectedItems.removeAll(items);
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notifyListeners();
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}
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void clearSelection() {
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_selectedItems.clear();
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notifyListeners();
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}
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void toggleSelection(T item) {
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if (!_isSelecting) select();
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if (!_selectedItems.remove(item)) _selectedItems.add(item);
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notifyListeners();
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}
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}
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