ios - UICollectionViewCell 在滚动时用动画移除空间

Question

我对 UICollectionViewCell 设计布局有疑问。我需要在 UICollectionView Cell 之间滚动时用动画删除空间，我已经尝试了一些 UICollectionView 的委托(delegate)方法，比如 -

• CollectionView - minimumLineSpacingForSectionAtIndex
• CollectionView - minimumInteritemSpacingForSectionAtIndex
• UIEdgeInsetsMake(0,0,0,0);
• scrollViewDidEndDragging

但达不到标准。这是代码:

  - (CGSize)collectionView:(UICollectionView *)collectionView
              layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
  {
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    CGFloat screenWidth = screenRect.size.width;
    float cellWidth = screenWidth / 2.1; //Replace the divisor with the column count requirement. Make sure to have it in float.
    CGSize size = CGSizeMake(cellWidth, cellWidth);

    return size;
 }

  - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section 
 {
    return 1.0;
 }

 - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section 
 {
   return 1.0;
 }

 // Layout: Set Edges
 - (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section 
 {
   return UIEdgeInsetsMake(0,0,0,0);  // top, left, bottom, right
 }

 - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
 {
   UIEdgeInsetsMake(0,0,0,0); // after scroll cell space not remove. 
 }

Answer 1

我不完全明白你想做什么，但如果你想改变 Collection View 的布局属性并动画改变，最好的方法是调用 setLayout:animated: .

像这样——

UICollectionViewFlowLayout *layout = [UICollectionViewFlowLayout alloc] init];
layout.minimumLineSpacing = 1.0;
layout.minimumInteritemSpacing = 1.0;
layout.itemSize = CGSizeMake(cellWidth, cellHeight);

UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:frame collectionViewLayout:layout]

然后每当你想改变它时，只需调用 setLayout:animated: 方法:

UICollectionViewFlowLayout *layout = [UICollectionViewFlowLayout alloc] init];
initialLayout.minimumLineSpacing = 5.0;
initialLayout.minimumInteritemSpacing = 7.0;
layout.itemSize = CGSizeMake(newCellWidth, newCellHeight);

[collectionView setLayout:layout animated:YES];