从 Firebase 存储中检索图像以显示在 tableView 单元格上

Question

我只需要帮助我使用 firebase 构建 Instagram 克隆，我在发布提要时遇到问题，我无法从 firebase 存储中检索图像以显示在 tableView 单元格上，请您帮帮我:(

导入 UIKit

导入 FirebaseAuth

导入 Firebase 数据库

类 HomeViewController: UIViewController ,UITableViewDelegate {

@IBOutlet weak var tableview: UITableView!
var posts = [Post]()
override func viewDidLoad() {
    super.viewDidLoad()

    tableview.dataSource = self
    loadposts()

 //   var post = Post(captiontxt: "test", photoUrlString: "urll")
 //   print(post.caption)
 //   print(post.photoUrl)

}

func loadposts() {
    Database.database().reference().child("posts").observe(.childAdded){ (snapshot: DataSnapshot)in
        print(Thread.isMainThread)
          if let dict = snapshot.value  as? [String: Any]{
            let captiontxt = dict["caption"] as! String
            let photoUrlString = dict["photoUrl"] as! String
           let post = Post(captiontxt: captiontxt, photoUrlString: photoUrlString )
            self.posts.append(post)
            print(self.posts)
            self.tableview.reloadData()
        }
    }
}

@IBAction func logout(_ sender: Any) {
    do {
        try Auth.auth().signOut()
    }catch let logoutErrorr{
        print(logoutErrorr)
    }
    let storyboard = UIStoryboard(name: "Start", bundle: nil)
    let signinVC = storyboard.instantiateViewController(withIdentifier: "SigninViewController")
    self.present(signinVC, animated: true, completion: nil)


}

} 扩展 HomeViewController：UITableViewDataSource{ func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 返回posts.count

}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableview.dequeueReusableCell(withIdentifier: "imagecell", for: indexPath) as! PostCellTableViewCell
   cell.captionLabel.text = posts[indexPath.row].caption
    cell.postimage.image =  posts[indexPath.row].photoUrl
   // print(cell.captionLabel.text)
   // print(cell.daysLabel.text)


    return cell
}

}

enter code here

---

导入基础 类帖子{ var 标题：字符串 var photoUrl: 字符串

init(captiontxt: String, photoUrlString: String) {
    caption = captiontxt
    photoUrl = photoUrlString

}

}

Answer 1

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableview.dequeueReusableCell(withIdentifier: "imagecell", for: indexPath) as! PostCellTableViewCell

    cell.postimage.image = nil

    cell.tag += 1
    let tag = cell.tag

    cell.captionLabel.text = posts[indexPath.row].caption

    let photoUrl = posts[indexPath.row].photoUrl

    getImage(url: photoUrl) { photo in
        if photo != nil {
            if cell.tag == tag {
                DispatchQueue.main.async {
                    cell.postimage.image = photo
                }
            }
        }
    }

    return cell
}

func getImage(url: String, completion: @escaping (UIImage?) -> ()) {
    URLSession.shared.dataTask(with: URL(string: url)!) { data, response, error in
        if error == nil {
            completion(UIImage(data: data!))
        } else {
            completion(nil)
        }
    }.resume()
}