忽略 UICollectionViewCell 的自定义高度

Question

我已经设置了一个 UICollectionView ，如下所示。我正在尝试设置自定义单元格高度，以便集合在必须滚动之前适合屏幕上的 3 个单元格。但是，这种定制工作不起作用或似乎被忽略了。有谁知道我做错了什么？

class CoopOverviewViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {

    @IBOutlet weak var CampaignBrandSliderBackground: UIView!
    @IBOutlet weak var CampaignBrandSlider: UISegmentedControl!
    @IBOutlet weak var CampaignCollectionView: UICollectionView!

    // TODO: load real data and replace with campaign model
    let campaignImages: [UIImage] = [UIImage(named: "icon-black")!,UIImage(named: "icon-white")!,UIImage(named: "icon-black")!,UIImage(named: "icon-white")!]
    let apiService = APIService()

    override func viewDidLoad() {
        super.viewDidLoad()
        CampaignBrandSliderBackground.layer.cornerRadius = 10

        // do other stuff...

        // Conform to UICollectionViewDelegate Protocol:
        CampaignCollectionView.dataSource = self
        CampaignCollectionView.delegate = self


        // Adjust Layout of CollectionViewCell: set cell height so that the collection fits 3 cells
        var cellLayout = self.CampaignCollectionView.collectionViewLayout as! UICollectionViewFlowLayout
        cellLayout.itemSize = CGSize(width: self.CampaignCollectionView.frame.size.width, height: self.CampaignCollectionView.frame.size.height/3) 

// ???: 自定义高度似乎被忽略了 }

    // Conform to UICollectionViewDataSource Protocol:
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return campaignImages.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let campaignCell = collectionView.dequeueReusableCell(withReuseIdentifier: "CampaignTileViewCell", for: indexPath) as! CampaignTileViewCellController
        campaignCell.CampaignBackgroundImage.image = campaignImages[indexPath.item]

        return campaignCell
    }

Answer 1

UICollectionView有一个Estimate Size属性，它限制了要设置的自定义高度。您可以从故事板更新其值。选择UICollectionView -> Size Inspector -> Estimate Size并将其值设置为None。这样你的自定义高度就会像魅力一样工作！