Ios 正在尝试在一个视图控制器中获取两个UICollection视图。只有一个出现了

我正在尝试为我正在开发的应用程序创建两个UICollectionView。我能够得到一个，由Firebase填充显示（imageCollection）。不幸的是，我无法显示第二个（popImageCollection）。我所有的插座都在那里。我不确定我到底做错了什么

这是我的视图控制器：

import UIKit
import Firebase
import FirebaseDatabase
import SDWebImage

class ViewController: UIViewController, UICollectionViewDataSource {
    @IBOutlet weak var popImageCollection: UICollectionView!
    @IBOutlet weak var imageCollection: UICollectionView!

    var customImageFlowLayout = CustomImageFlowLayout()
    var images = [BlogInsta]()
    var popImageArray = [UIImage]()

    var dbRef: DatabaseReference!
    var dbPopularRef: DatabaseReference!

    override func viewDidLoad() {
        super.viewDidLoad()

        dbRef = Database.database().reference().child("images")
        dbPopularRef = Database.database().reference().child("popular")
        loadDB()
        loadImages()
        customImageFlowLayout = CustomImageFlowLayout()
        imageCollection.backgroundColor = .white

        popImageCollection.delegate = self as? UICollectionViewDelegate
        popImageCollection.dataSource = self

        imageCollection.delegate = self as? UICollectionViewDelegate
        imageCollection.dataSource = self

        self.view.addSubview(popImageCollection)
        self.view.addSubview(imageCollection)
    }

    func loadImages() {
        popImageArray.append(UIImage(named: "1")!)
        self.popImageCollection.reloadData()
    }

    func loadDB() {
        dbRef.observe(DataEventType.value, with: { (snapshot) in
            var newImages = [BlogInsta]()
            for BlogInstaSnapshot in snapshot.children {
                let blogInstaObject = BlogInsta(snapshot: BlogInstaSnapshot as! DataSnapshot)
                newImages.append(blogInstaObject)
            }

            self.images = newImages
            self.imageCollection.reloadData()
        })
    }

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

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return images.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        if collectionView == self.imageCollection {
            let cell = imageCollection.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! ImageCollectionViewCell
            let image = images[indexPath.row]
            cell.imageView.sd_setImage(with: URL(string: image.url), placeholderImage: UIImage(named: "1"))
            return cell
        } else {
            let cellB = popImageCollection.dequeueReusableCell(withReuseIdentifier: "popCell", for: indexPath) as! PopularCollectionViewCell
            let popPhotos = popImageArray[indexPath.row]
            cellB.popularImageView.image = popPhotos
            return cellB
        }
    }
}

---

如果集合在IB中，请不要再次添加它们

self.view.addSubview(popImageCollection) // remove
self.view.addSubview(imageCollection) // remove

也

//

委托应该在类声明中，因为在运行时不能设置为nil

class ViewController: UIViewController, UICollectionViewDataSource , UICollectionViewDelegate {

---

你试过UI调试吗？我在代码中看不到帧设置，因此我相信popImageCollection在imageCollection后面。此外，如果您使用的是IBOutlets，为什么要将collectionView添加为子视图？Life saver！非常感谢。

class ViewController: UIViewController, UICollectionViewDataSource , UICollectionViewDelegate {