UICollectionView删除空格/标题iOS11

我有一个UICollection视图,看起来像这样(见两个紫色和蓝色边框):

在iOS 10上没有标题/空白,但在iOS11上有.我已经尝试了这里提到的所有内容:如何以编程方式在UICollectionView中启用/禁用节头？

我的代码目前看起来像这样:

- (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为零.

我错过了什么？为什么我的UICollectionView仍然有空格？

在iOS 11中,对UIScrollView进行了一些更改.

尝试设置contentInsetAdjustmentBehavior属性

collectionView.cOntentInsetAdjustmentBehavior= UIScrollViewContentInsetAdjustmentNever;