ios - CollectionView 方向问题

Question

I currently have a collection view with a grid of images on it, when selecting an image this segues to another collection view with a full screen image on it.

为此，我正在使用:

    - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if ([segue.identifier isEqualToString:@"collectionView"])

    {
        QuartzDetailViewController *destViewController = (QuartzDetailViewController *)segue.destinationViewController;

        NSIndexPath *indexPath = [[self.collectionView indexPathsForSelectedItems] objectAtIndex:0];

        destViewController.startingIndexPath = indexPath;

        [destViewController.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:NO];

        [self.collectionView deselectItemAtIndexPath:indexPath animated:NO];
    }
}

然后在我的详细 View 中:

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if (_startingIndexPath) {
    NSInteger currentIndex = floor((scrollView.contentOffset.x - scrollView.bounds.size.width / 2) / scrollView.bounds.size.width) + 1;
    if (currentIndex < [self.quartzImages count]) {
        self.title = self.quartzImages[currentIndex][@"name"];
    }
}
}

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    UICollectionViewFlowLayout *layout = (UICollectionViewFlowLayout *)self.collectionView.collectionViewLayout;
    layout.itemSize = self.view.bounds.size;

    [self.collectionView scrollToItemAtIndexPath:self.startingIndexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:NO];
}

当我旋转到横向时，图像消失并且顶部的标题发生变化，如果我返回网格然后再次选择一个单元格，它将再次转到详细 View ，但标题是针对不同的单元格和图像显示两个不同图像之间的一半。

当我旋转设备时，我也在日志中收到以下消息:

2013-06-04 17:39:53.869 PhotoApp[6866:907] the behavior of the UICollectionViewFlowLayout is not defined because:
2013-06-04 17:39:53.877 PhotoApp[6866:907] the item height must be less that the height of the UICollectionView minus the section insets top and bottom values.

我怎样才能更正它以支持方向。

谢谢

Answer 1

您需要使 Collection View 的布局无效，因为纵向单元格的大小对于横向方向来说太大了。

在您的父级 UIViewController 中编写类似的内容应该可以解决您的问题:

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
  [self.collectionView.collectionViewLayout invalidateLayout];
}