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swift - UIcollection 视图中未显示数据。我做错了什么

问题描述

我UICollectionView的没有显示数据，我做错了什么？

这是集合视图控制器类：

class SongfeedViewController: UIViewController,UICollectionViewDelegate,UICollectionViewDataSource {

    @IBOutlet weak var collectionview: UICollectionView!
    
    var posts = [Post]()
    
    private var song = [songs]()
    private var songsCollection : CollectionReference!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        songsCollection = Firestore.firestore().collection("Songs")
    }
    
    override func viewWillAppear(_ animated: Bool) 
    {
        songsCollection.getDocuments { (snapshot, error) in
            if let err = error{
                print("Error Fetching Docs:\(err)")
            
            } else {
                guard let snap = snapshot else{return}
                for document in snap.documents{
                    let data = document.data()
                    let fullname = data["fullname"] as? String ?? "Anonymous"
                    let songname = data["songname"] as? String ?? "Anonymous"
                    let youtubelink = data["youtubelink"] as? String ?? "Anonymous"
                    let moneyoffer = data["moneyoffer"] as? String ?? "Anonymous"
                    let instalink = data["instalink"] as? String ?? "Anonymous"
                    
                    let newsong = songs(fullname: fullname, songname: songname, moneyoffer: moneyoffer, youtubelink: youtubelink, instalink: instalink)
                    
                    self.song.append(newsong)
                }

                self.collectionview.reloadData()
            }
        }
    }
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return self.posts.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionview.dequeueReusableCell(withReuseIdentifier: "postCell", for: indexPath) as! postCell
        
        cell.artistnamelabel.text = self.posts[indexPath.row].fullname
        cell.moneyofferlabel.text = self.posts[indexPath.row].moneyoffer
        cell.instaUsernnamelabel.text = self.posts[indexPath.row].instalink
        cell.songnamelabel.text = self.posts[indexPath.row].songname
        cell.youtubelinklabel.text = self.posts[indexPath.row].youtubelink
        
        return cell
    }

来自 firestore 的数据未显示在 UI 集合视图上。

我的邮政信箱中的代码如下：

import UIKit

class postCell: UICollectionViewCell {
    @IBOutlet weak var artistnamelabel: UITextField!
    @IBOutlet weak var moneyofferlabel: UITextField!
    @IBOutlet weak var songnamelabel: UITextField!
    
    @IBOutlet weak var youtubelinklabel: UITextField!
    @IBOutlet weak var instaUsernnamelabel: UITextField! 
}

标签： swiftxcodefirebasegoogle-cloud-firestorestoryboard

解决方案

您的numberOfItemsInSection和cellForItemAt函数正在查看posts数组

但是在您的闭包中您将数据插入到song变量中

重新加载集合时posts仍然为空

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