解决问题:
UICollectionView下嵌套UITableView作为多个列表时侧滑返回失效及cell侧滑删除失效的问题

继承自UICollectionView：

@implementation XYCollectionView
// 是否允许同时支持多个手势，默认是不支持多个手势
// 返回yes表示支持多个手势
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    if (gestureRecognizer.view == self) {
        if (self.contentOffset.x <= 0 && gestureRecognizer.state != UIGestureRecognizerStatePossible) {
            return YES;
        }
    }
    return NO;
}
// 每次触摸屏幕时保证collectionView第一时间可以响应滚动
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    self.scrollEnabled = YES;
    return [super hitTest:point withEvent:event];
}
@end

设置下面这个是为了触发侧滑返回时collectionView不再去滚动cell， 在CollectionView的代理方法中，根据collectionView的contentOffse让其是否可以滚动

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
UIPanGestureRecognizer *pan = (UICollectionView *)scrollView.panGestureRecognizer
    if (pan.view == scrollView) {
        if (_switchState == 0 && _downloadingArr.count > 0) {
            for (NSInteger i = 0; i < _downloadingArr.count; ++i) {
                NSIndexPath *indexPath = [NSIndexPath indexPathForRow:i inSection:0];
                UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
              // 此处是为了解决cell左滑删除失效的问题
                if (cell && [cell isKindOfClass:[DownloadingCell class]]) {
                    CGPoint location = [pan locationInView: scrollView];
                    if (location.y > 0 && location.y < cell.frame.size.height*(i+1)) {
                       scrollView.scrollEnabled = NO;
                    }
                }
            }
        }
        
        // 此处是为了解决滑动到第一个cell左侧边缘时侧滑返回失效问题
        if (scrollView .contentOffset.x < 0) {
            scrollView.scrollEnabled = NO;
        } else {
            scrollView.scrollEnabled = YES;
        }
    }
    
}

最终效果：每次又滑到第一个cell边缘时，就会触发侧滑返回