Question

我想用标题创建UICollectionView。我在mainStoryBoard上设置了Collection Reusable View，但是设备上没有显示任何内容。我试图搜索，但无法找出它为什么没有出现。我

主要故事板

在设备上

导入UIKit

class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {


    @IBOutlet weak var collectionView: UICollectionView!

    var images = ["medal1","medal2","medal3","medal4","medal5","medal6","medal7","medal8","medal9","medal10","medal1","medal2","medal3","medal14"]

    var texts = ["hi","yes","hoo","such","hi","yes","hoo","such","hi","yes","hoo","such","hi","yes"]

    override func viewDidLoad() {
        super.viewDidLoad()



        collectionView.delegate = self
        collectionView.dataSource = self

    }

    public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

        return images.count
    }

    public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CustomCell", for: indexPath) as! CustomCell

        cell.myImage.image = UIImage(named: images[indexPath.row])

        cell.achievementLabel.text = texts[indexPath.row]

        return cell

    }

    func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return 1
    }






}


import UIKit

集合视图 class CustomCell：UICollectionViewCell {

    @IBOutlet weak var myImage: UIImageView!

    @IBOutlet weak var achievementLabel: UILabel!

}

集合可重用视图的类导入UIKit

class CollectionReusableView: UICollectionReusableView {

    @IBOutlet weak var reuseableVimage: UIImageView!
}


> import UIKit

class ViewController: UIViewController, UICollectionViewDelegate {


    @IBOutlet weak var collectionView: UICollectionView!

    var images = ["medal1","medal2","medal3","medal4","medal5","medal6","medal7","medal8","medal9","medal10","medal1","medal2","medal3","medal14"]

    var texts = ["hi","yes","hoo","such","hi","yes","hoo","such","hi","yes","hoo","such","hi","yes"]

    override func viewDidLoad() {
        super.viewDidLoad()



        collectionView.delegate = self


    }

    func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
        if kind == UICollectionElementKindSectionHeader {
            let view = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "HeaderView", for: indexPath)
            // do any programmatic customization, if any, here
            return view
        }
        fatalError("Unexpected kind")








}
}

Answer 1

您必须实施viewForSupplementaryElementOfKind：

酌情对UICollectionElementKindSectionHeader或UICollectionElementKindSectionFooter实施collectionView(_:viewForSupplementaryElementOfKind:at:)。

func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    if kind == UICollectionElementKindSectionHeader {
        let view = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "CollectionReusableView", for: indexPath) as! CollectionReusableView
        // do any programmatic customization, if any, here
        return view
    }
    fatalError("Unexpected kind")
}

确保IB中的标题可重用视图
- 适当的基类;和
- 适当的＆＃34;重用标识符＆＃34;
在IB中，确保收藏视图＆＃34;附件＆＃34;接下来有选中标记＆＃34; Section Header＆＃34;和＃34;部分页脚＆＃34;，视情况而定。

Answer 2

尝试实现此目的。 RayWenderlich中有一个可能对您有用的示例：https://www.raywenderlich.com/136161/uicollectionview-tutorial-reusable-views-selection-reordering

override func collectionView(_ collectionView: UICollectionView,
                             viewForSupplementaryElementOfKind kind: String,
                             at indexPath: IndexPath) -> UICollectionReusableView {
switch kind {
case UICollectionElementKindSectionHeader:
    let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind,
                                                                           withReuseIdentifier: "CollectionReusableView",
                                                                           for: indexPath) as! CollectionReusableView
    headerView.reuseableVimage ....
    return headerView
default:
    assert(false, "Unexpected element kind")
}
}

为什么不显示集合可重用视图？

2 个答案: