如何使用URL Swift 3下载图像？ [英] How to download image with URL Swift 3?

问题描述

我是一个新手开发者，我正在尝试从URL下载并显示图像并将其显示在UIImage视图中。我尝试过多种方法，使用以前提出的问题和网页信息，但它不断出现多个错误。

Im a newbie dev and I'm trying to download and display an image from a URL and display it in a UIImage view. I've tried a multiple methods using info from previously asked questions and thr web but it keeps coming up with multiple errors.

推荐答案

在 Leo Dabus的回答。我将在下面的问题中包含相关位。

There's an excellent example of how to do this in Leo Dabus's answer here. I'll include the relevant bits to your question below.

使用该帖子中的代码，我发现一种更简单，更清晰的方法是添加扩展名 UIImageView ：

Using code from that post, I've found one of the easier and cleaner ways is to add an extension to UIImageView:

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式从视图控制器中获取图像：

Then you can just grab the image from your view controller using:

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

这篇关于如何使用URL Swift 3下载图像？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！