可移动的CollectionViewCell

最新推荐文章于 2022-06-06 15:02:19 发布

转载最新推荐文章于 2022-06-06 15:02:19 发布 · 844 阅读

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#移动

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本文介绍如何使用UICollectionView实现拖动效果及数据交换功能。通过创建UICollectionView并设置代理，实现手势监听，允许用户拖动UICollectionView中的cell，并在拖动结束后更新数据源的位置。

1.创建collectionView并设置代理

- (UICollectionView *)collectionView{
    if (_collectionView == nil) {
        UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
        layout.itemSize = CGSizeMake(50, 50);
        _collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 20, self.view.bounds.size.width, self.view.bounds.size.height) collectionViewLayout:layout];
        layout.minimumLineSpacing = 10;
        layout.minimumInteritemSpacing = 10;
        [_collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"Cell"];
        _collectionView.backgroundColor = [UIColor cyanColor];
        _collectionView.dataSource = self;
       //此处给其增加长按手势，用此手势触发cell移动效果
        UILongPressGestureRecognizer *longGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handlelongGesture:)];
        [_collectionView addGestureRecognizer:longGesture];
    }
    return _collectionView;
}

2.设置其资源

_dataSource = [NSMutableArray array];
    for (int i = 1; i <= 50; i++) {
        NSString *imageName = [NSString stringWithFormat:@"%d",i];
        [_dataSource addObject:imageName];
    }

3.监听手势，并设置其允许移动cell和交换资源

- (void)handlelongGesture:(UILongPressGestureRecognizer *)longGesture {
    //判断手势状态
    switch (longGesture.state) {
        case UIGestureRecognizerStateBegan:{
            //判断手势落点位置是否在路径上
            NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:[longGesture locationInView:self.collectionView]];
            if (indexPath == nil) {
                break;
            }
            //在路径上则开始移动该路径上的cell
            [self.collectionView beginInteractiveMovementForItemAtIndexPath:indexPath];
        }
            break;
        case UIGestureRecognizerStateChanged:
            //移动过程当中随时更新cell位置
            [self.collectionView updateInteractiveMovementTargetPosition:[longGesture locationInView:self.collectionView]];
            break;
        case UIGestureRecognizerStateEnded:
            //移动结束后关闭cell移动
            [self.collectionView endInteractiveMovement];
            break;
        default:
            [self.collectionView cancelInteractiveMovement];
            break;
    }
}

- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath{
    //返回YES允许其item移动
    return YES;
}

- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath*)destinationIndexPath {
    //取出源item数据
    id objc = [_dataSource objectAtIndex:sourceIndexPath.item];
    //从资源数组中移除该数据
    [_dataSource removeObject:objc];
    //将数据插入到资源数组中的目标位置上
    [_dataSource insertObject:objc atIndex:destinationIndexPath.item];
}