如何从URL加载UIImage？

debugcn 发表于 Dev

Ben

我有以下问题：

致命错误：解开Optional值时意外发现nil

@IBOutlet weak var DetailImageView1: UIImageView!
@IBOutlet weak var DetailLabel: UILabel!

@IBOutlet weak var DetailLabel2: UILabel!

var SentData1: String!
var SentData2: String!
var SentData3: NSURL!

 override func viewDidLoad() {
    super.viewDidLoad()



    DetailLabel.text = SentData1
    DetailLabel2.text = SentData2
    let url = NSURL(string: "\(SentData3)")
    let data = NSData(contentsOfURL: url!)
    DetailImageView1.image = UIImage(data: data!)

我正在从一个URL拍摄图片，并从我以前的视图控制器到该URL的URL链接中进行筛选。然后，我创建了SentData3：NSURL！现在，我必须在DetailImageView1.image中显示图片，但是当我尝试测试应用程序时出现错误。

如果有人能告诉我错误我会很高兴。

停留

您可以为SwiftUI尝试一下：

import SwiftUI

struct RemoteImage: View {
private enum LoadState {
    case loading, success, failure
}

private class Loader: ObservableObject {
    var data = Data()
    var state = LoadState.loading

    init(url: String) {
        guard let parsedURL = URL(string: url) else {
            fatalError("Invalid URL: \(url)")
        }

        URLSession.shared.dataTask(with: parsedURL) { data, response, error in
            if let data = data, data.count > 0 {
                self.data = data
                self.state = .success
            } else {
                self.state = .failure
            }

            DispatchQueue.main.async {
                self.objectWillChange.send()
            }
        }.resume()
    }
}

@StateObject private var loader: Loader
var loading: Image
var failure: Image

var body: some View {
    selectImage()
        .resizable()
}

init(url: String, loading: Image = Image(systemName: "photo"), failure: Image = Image(systemName: "multiply.circle")) {
    _loader = StateObject(wrappedValue: Loader(url: url))
    self.loading = loading
    self.failure = failure
}

private func selectImage() -> Image {
    switch loader.state {
    case .loading:
        return loading
    case .failure:
        return failure
    default:
        if let image = UIImage(data: loader.data) {
            return Image(uiImage: image)
        } else {
            return failure
        }
    }
}
}

然后在您的视图中使用它：

struct ContentView: View {
let jsonURL = "https://cf.geekdo-images.com/thumb/img/sD_qvrzIbvfobJj0ZDAaq-TnQPs=/fit-in/200x150/pic2649952.jpg"

var body: some View {
    RemoteImage(url: jsonURL)
        .aspectRatio(contentMode: .fit)
        .frame(width: 200)
}
}

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