SwiftUI:当照片选择器关闭时如何调用函数

Question

我使用SwiftUI类中的照片选择器将照片和视频加载到数组中。现在，在选择器中选择这些图像后，我将显示它们。效果很好。

相反，当我单击"Add“按钮并将该数组中的对象上传到Cloudinary进行处理和存储时，我想运行一个函数。我可以通过在选择器之外的一个单独的按钮手动实现这一点，但是对于最好的UX，我认为这个函数应该在选中"Add“按钮时自动运行。

当单击"Add“按钮时，如何运行函数？是否需要检查数组是否为空，是否存在其他条件？

下面是采摘者的照片：

​

下面是选择代码：

import SwiftUI
import PhotosUI

struct PhotoPicker: UIViewControllerRepresentable {
typealias UIViewControllerType = PHPickerViewController

@ObservedObject var mediaItems: PickedMediaItems
var didFinishPicking: (_ didSelectItems: Bool) -> Void

func makeUIViewController(context: Context) -> PHPickerViewController {
    var config = PHPickerConfiguration()
    config.filter = .any(of: [.images, .videos, .livePhotos])
    config.selectionLimit = 0
    config.preferredAssetRepresentationMode = .current
    
    let controller = PHPickerViewController(configuration: config)
    controller.delegate = context.coordinator
    return controller
}

func updateUIViewController(_ uiViewController: PHPickerViewController, context: Context) {
    
}


func makeCoordinator() -> Coordinator {
    Coordinator(with: self)
}


class Coordinator: PHPickerViewControllerDelegate {
    var photoPicker: PhotoPicker
    
    init(with photoPicker: PhotoPicker) {
        self.photoPicker = photoPicker
    }
    
    func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
        photoPicker.didFinishPicking(!results.isEmpty)
        
        guard !results.isEmpty else {
            return
        }
        
        for result in results {
            let itemProvider = result.itemProvider
            
            guard let typeIdentifier = itemProvider.registeredTypeIdentifiers.first,
                  let utType = UTType(typeIdentifier)
            else { continue }
            
            if utType.conforms(to: .image) {
                self.getPhoto(from: itemProvider, isLivePhoto: false)
            } else if utType.conforms(to: .movie) {
                self.getVideo(from: itemProvider, typeIdentifier: typeIdentifier)
            } else {
                self.getPhoto(from: itemProvider, isLivePhoto: true)
            }
        }
    }
    
    
    private func getPhoto(from itemProvider: NSItemProvider, isLivePhoto: Bool) {
        let objectType: NSItemProviderReading.Type = !isLivePhoto ? UIImage.self : PHLivePhoto.self
        
        if itemProvider.canLoadObject(ofClass: objectType) {
            itemProvider.loadObject(ofClass: objectType) { object, error in
                if let error = error {
                    print(error.localizedDescription)
                }
                
                if !isLivePhoto {
                    if let image = object as? UIImage {
                        DispatchQueue.main.async {
                            self.photoPicker.mediaItems.append(item: PhotoPickerModel(with: image))
                        }
                    }
                } else {
                    if let livePhoto = object as? PHLivePhoto {
                        DispatchQueue.main.async {
                            self.photoPicker.mediaItems.append(item: PhotoPickerModel(with: livePhoto))
                        }
                    }
                }
            }
        }
    }
    
    
    private func getVideo(from itemProvider: NSItemProvider, typeIdentifier: String) {
        itemProvider.loadFileRepresentation(forTypeIdentifier: typeIdentifier) { url, error in
            if let error = error {
                print(error.localizedDescription)
            }
            
            guard let url = url else { return }
            
            let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
            guard let targetURL = documentsDirectory?.appendingPathComponent(url.lastPathComponent) else { return }
            
            do {
                if FileManager.default.fileExists(atPath: targetURL.path) {
                    try FileManager.default.removeItem(at: targetURL)
                }
                
                try FileManager.default.copyItem(at: url, to: targetURL)
                
                DispatchQueue.main.async {
                    self.photoPicker.mediaItems.append(item: PhotoPickerModel(with: targetURL))
                }
            } catch {
                print(error.localizedDescription)
            }
        }
    }
}
}

Answer 1

我将这个类添加到视图中：

class PickerStatus: ObservableObject {
    var status: Bool = false
}

然后将这一行添加到PhotoPicker中：

@ObservedObject var finishedSelection: PickerStatus

然后，在协调员中，我补充说：

for result in results {
                
     self.photoPicker.finishedSelection.status = true

...
}

现在，在我的视图中，我可以设置ObservedObject的实例，将它传递到我的子视图中，包括PhotoPicker，并检查相同的观察对象的值：

@ObservedObject var finishedSelection = PickerStatus()