UICollectionView 移除 whitespace/header iOS11

Question

我有一个 UICollection 视图，它看起来像这样（看到两个紫色和蓝色边框）：

在 iOS 10 上没有 header/whitespace，但在 iOS11 上有。我已经尝试了这里提到的所有内容：How can I enable/disable section headers in UICollectionView programmatically?

我的代码目前是这样的：

- (void) viewDidLoad
{
    [super viewDidLoad];

    autocompleteLayout = [[SQLProAutocompleteFlowLayout alloc] init];
    autocompleteLayout.headerReferenceSize = CGSizeZero;

    autocompleteCollectionView = [[UICollectionView alloc] initWithFrame: CGRectZero
                                                    collectionViewLayout: autocompleteLayout];

    autocompleteCollectionView.insetsLayoutMarginsFromSafeArea = NO;

    [self.view addSubview: autocompleteCollectionView];

    // removed layout code (leftAnchor, rightAnchor, topAnchor, bottomAnchor).

    autocompleteCollectionView.delegate = self;
    autocompleteCollectionView.dataSource = self;

    // Removed nib register code

    self.view.layer.borderColor = [UIColor redColor].CGColor;
    self.view.layer.borderWidth = 1;

    autocompleteCollectionView.layer.borderColor = [UIColor blueColor].CGColor;
    autocompleteCollectionView.layer.borderWidth = 2;
}

- (CGSize) collectionView: (UICollectionView *) collectionView
                   layout: (UICollectionViewLayout *) collectionViewLayout
referenceSizeForHeaderInSection:(NSInteger)section
{
    return CGSizeZero;
}

- (CGSize)collectionView:(UICollectionView *)collectionView
                  layout:(UICollectionViewLayout *)collectionViewLayout
referenceSizeForFooterInSection:(NSInteger)section
{
    return CGSizeZero;
}

我的 FlowLayout 看起来像这样：

- (void) setupLayout
{
    self.minimumInteritemSpacing = 0;
    self.minimumLineSpacing      = 0;
    self.scrollDirection         = UICollectionViewScrollDirectionVertical;
} // End of setupLayout

- (void) prepareLayout
{
    [super setItemSize: [self itemSize]];
    [super setSectionInset: [self sectionInset]];
    self.minimumLineSpacing = 0;

    [super prepareLayout];
} // End of prepareLayout

- (CGFloat) itemWidth
{
    return self.collectionView.frame.size.width;
}

- (CGSize) itemSize
{
    CGSize result = CGSizeMake(self.collectionView.frame.size.width,
                               rowHeight);

    return result;
}

- (void) setItemSize:(CGSize)itemSize
{
    self.itemSize = CGSizeMake(self.collectionView.frame.size.width,
                               rowHeight);
}

- (CGPoint) targetContentOffsetForProposedContentOffset:(CGPoint)proposedContentOffset
{
    return CGPointZero;
}

我还验证了 UICollectionView 的 contentInset 已归零。

我错过了什么？为什么我的 UICollectionView 仍然有空格？

Answer 1

试试这个：

 self.automaticallyAdjustsScrollViewInsets = false
    - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
        return 0;
    }

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
    return 0;
}


- (UIEdgeInsets)collectionView:
(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
   return UIEdgeInsetsMake(-25,0,0,0);  // top, left, bottom, right
}

Answer 2

在iOS11中，UIScrollView发生了一些变化。

尝试设置 contentInsetAdjustmentBehavior 属性

collectionView.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever;

UICollectionView 移除 whitespace/header iOS11

UICollectionView remove whitespace/header iOS11

ios

uicollectionview

uicollectionviewlayout

ios11