ios - 如何使用 URL Swift 3 下载图像？

Question

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Answer 1

在 Leo Dabus's answer here 中有一个很好的例子说明如何做到这一点.我将在下面包含与您的问题相关的内容。

使用该帖子中的代码，我发现一种更简单、更简洁的方法是向 UIImageView 添加扩展:

extension UIImageView {
    func downloadedFrom(url: URL, contentMode mode: UIViewContentMode = .scaleAspectFit) {
        contentMode = mode
        URLSession.shared.dataTask(with: url) { (data, response, error) in
            guard let httpURLResponse = response as? HTTPURLResponse, httpURLResponse.statusCode == 200,
                let mimeType = response?.mimeType, mimeType.hasPrefix("image"),
                let data = data, error == nil,
                let image = UIImage(data: data)
                else { return }
            DispatchQueue.main.async() { () -> Void in
                self.image = image
            }
        }.resume()
    }
    func downloadedFrom(link: String, contentMode mode: UIViewContentMode = .scaleAspectFit) {
        guard let url = URL(string: link) else { return }
        downloadedFrom(url: url, contentMode: mode)
    }
}

然后您可以使用以下方法从 View Controller 中获取图像:

if let url = URL.init(string: urlString) {
    imageView.downloadedFrom(url: url)
}