ios - 如何使用 Firebase 将新照片上传到 collectionView 单元格？

Question

此处的代码允许我将一张照片上传和下载到 Firebase 并将其保存为用户默认设置，但我试图弄清楚如何在 collectionView 单元格中执行此操作并显示所需的照片数量，添加新项目

    import UIKit
    import FirebaseStorage
    
        class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
        
            private let storage = Storage.storage().reference()
            
            @IBOutlet var imageView: UIImageView!
            @IBOutlet var label: UILabel!
            
        override func viewDidLoad() {
                super.viewDidLoad()
                // Do any additional setup after loading the view.
                label.numberOfLines = 0
                guard let urlString = UserDefaults.standard.value(forKey: "url") as? String, let url = URL(string: urlString) else {
                    return
                }
                label.text = urlString
                let task = URLSession.shared.dataTask(with: url, completionHandler: { data,_,error in
                    guard let data = data, error == nil else {
                        return
                }
                DispatchQueue.main.async {
                    let image = UIImage(data: data)
                    self.imageView.image = image
                    }
            })
                task.resume()
        }
            @IBAction func didTapButton() {
                let picker = UIImagePickerController()
                picker.sourceType = .photoLibrary
                picker.delegate = self
                picker.allowsEditing = true
                present(picker, animated: true, completion: nil)
            }
            func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
                picker.dismiss(animated: true, completion: nil)
                guard let image = info[UIImagePickerController.InfoKey.editedImage] as? UIImage else {
                    return
                }
                guard let imageData = image.pngData() else {
                    return
                }
                storage.child("Images/Photo.png").putData(imageData, metadata: nil) { (_, error) in
                    guard error == nil else {
                        print("Failed to Upload Data")
                        return
                    }
                    self.storage.child("Images/Photo.png").downloadURL(completion: {url, error in
                        guard let url = url, error == nil else {
                            return
                        }
                        let urlString = url.absoluteString
                        DispatchQueue.main.async {
                            self.label.text = urlString
                            self.imageView.image = image
                        }
                        print("Download URL: \(urlString)")
                        UserDefaults.standard.set(urlString, forKey: "url")
                    })
                }
                // Upload Image Data
                // Get Download URL
                // Save Download URL to userDefaults
            }
            func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
                picker.dismiss(animated: true, completion: nil)
            }
        }

Answer 1

要将图像上传到 Firebase 存储并在 Collection View 中显示它们，您可以使用以下步骤；

使用 URL 的数组设置 Collection View s(或 String s)作为其
数据源。如果需要，您可以使用自定义模型。

保留对您的 Firebase storage 的引用并上传图片。上传成功后，使用image reference获取上传图片的URL .

将网址保存在 Firebase Database 中(或 Cloud Firestore )。仅当您希望将 Collection View 与数据库同步并在上传新图像时对其进行更新时，才需要这样做。

为您的 Firebase database 添加一个监听器引用你有的地方
保存图像 URL。更新监听器内的本地 URLs 数组并重新加载 Collection View 。

如果您不想使用 Firebase database ，省略步骤 3 和 4，将图像 URL 保存到数组并立即重新加载 Collection View 。
我没有在此处添加 Collection View 设置的代码，因为这不是此答案的目标。

let storageRef = Storage.storage().reference(withPath: "images")
let databaseRef = Database.database().reference(withPath:"images")
var images: [String] = []

override func viewDidLoad() {
    super.viewDidLoad()
    
    addDatabaseListener()
}

private func addDatabaseListener() {
    databaseRef.observe(.childAdded) { (snapshot) in
        
        guard let value = snapshot.value as? [String: Any], let url = value["url"] as? String else { return }
        self.images.append(url)
        DispatchQueue.main.async {
            self.collectionView.reloadData()
        }
    }
}


func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    picker.dismiss(animated: true)
    guard let image = info[UIImagePickerController.InfoKey.editedImage] as? UIImage, let data = image.jpegData(compressionQuality: 0.1) else { return }

    let fileName = "\(Date.timeIntervalSinceReferenceDate).jpeg"
    let newImageRef = storageRef.child(fileName)
    
    newImageRef.putData(data, metadata: nil) { (_, error) in
        if let error = error {
            print("upload failed: ", error.localizedDescription)
            return
        }
        
        newImageRef.downloadURL { (url, error) in
            if let error = error {
                print("error: ", error.localizedDescription)
                return
            }
            self.databaseRef.childByAutoId().setValue(["url": url?.absoluteString])
        }
    }
    
}