let url = NSURL.URLWithString("http://live-wallpaper.net/iphone/img/app/i/p/iphone-4s-wallpapers-mobile-backgrounds-dark_2466f886de3472ef1fa968033f1da3e1_raw_1087fae1932cec8837695934b7eb1250_raw.jpg");
var err: NSError?
var imageData :NSData = NSData.dataWithContentsOfURL(url,options: NSDataReadingOptions.DataReadingMappedIfSafe, error: &err)
var bgImage = UIImage(data:imageData)

Swift 2.0:

1)

if let url = NSURL(string: "http://etc...") {
    if let data = NSData(contentsOfURL: url) {
        imageURL.image = UIImage(data: data)
    }        
}

OR

imageURL.image =
    NSURL(string: "http:// image name...")
    .flatMap { NSData(contentsOfURL: $0) }
    .flatMap { UIImage(data: $0) }

2)将此方法添加到VC或Extension中。

func load_image(urlString:String)
{   let imgURL: NSURL = NSURL(string: urlString)!
    let request: NSURLRequest = NSURLRequest(URL: imgURL)

    NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) { (response: NSURLResponse?, data: NSData?, error: NSError?) in

        if error == nil {
            self.image_element.image = UIImage(data: data)
        }
    }
}

用法:

self.load_image(" url strig here")

您可以使用pod SDWebImage来实现相同的功能。它很容易使用。你可以在SDWebImage这里获得文档

下面是示例代码

self.yourImage.sd_setImage(with: NSURL(string: StrUrl as String ) as URL!, placeholderImage: placeholderImage, options: SDWebImageOptions(rawValue: 0), completed: { (image, error, cacheType, imageURL) in
                if( error != nil)
                {
                    print("Error while displaying image" , (error?.localizedDescription)! as String)
                }
            })

class ImageStore: NSObject { 
    static let imageCache = NSCache<NSString, UIImage>()
}

extension UIImageView {
    func url(_ url: String?) {
        DispatchQueue.global().async { [weak self] in
            guard let stringURL = url, let url = URL(string: stringURL) else {
                return
            }
            func setImage(image:UIImage?) {
                DispatchQueue.main.async {
                    self?.image = image
                }
            }
            let urlToString = url.absoluteString as NSString
            if let cachedImage = ImageStore.imageCache.object(forKey: urlToString) {
                setImage(image: cachedImage)
            } else if let data = try? Data(contentsOf: url), let image = UIImage(data: data) {
                DispatchQueue.main.async {
                    ImageStore.imageCache.setObject(image, forKey: urlToString)
                    setImage(image: image)
                }
            }else {
                setImage(image: nil)
            }
        }
    }
}

用法:

let imageView = UIImageView()
imageView.url("image url")

斯威夫特 2.2 ||Xcode 7.3

我得到了惊人的成绩!!使用AlamofireImage swift库

它提供了多种功能，如:

异步下载 自动清除图像缓存，如果内存警告发生的应用程序 图像URL缓存 图像缓存 避免重复下载

在你的应用中很容易实现

步骤1安装吊舱

Alamofire 3 x 3。

宾夕法尼亚州’Alamofire’

AlamofireImage 2。4 . x

宾夕法尼亚州’AlamofireImage’

步骤2导入并使用

import Alamofire
import AlamofireImage

let downloadURL = NSURL(string: "http://cdn.sstatic.net/Sites/stackoverflow/company/Img/photos/big/6.jpg?v=f4b7c5fee820")!
imageView.af_setImageWithURL(downloadURL)

就是这样! !它会照顾好一切

非常感谢Alamofire的伙计们，让iDevelopers的生活变得简单了;)

Swift 3错误处理

let url = URL(string: arr[indexPath.row] as! String)
if url != nil {
    DispatchQueue.global().async {
        let data = try? Data(contentsOf: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check / try-catch
        DispatchQueue.main.async {
            if data != nil {
                cell.imgView.image = UIImage(data:data!)
            }else{
                cell.imgView.image = UIImage(named: "default.png")
            }
        }
    }
}

与扩展

extension UIImageView {

    func setCustomImage(_ imgURLString: String?) {
        guard let imageURLString = imgURLString else {
            self.image = UIImage(named: "default.png")
            return
        }
        DispatchQueue.global().async { [weak self] in
            let data = try? Data(contentsOf: URL(string: imageURLString)!)
            DispatchQueue.main.async {
                self?.image = data != nil ? UIImage(data: data!) : UIImage(named: "default.png")
            }
        }
    }
}

扩展使用

myImageView. setCustomImage("url")

具有缓存支持

let imageCache = NSCache<NSString, UIImage>()

extension UIImageView {

    func loadImageUsingCacheWithURLString(_ URLString: String, placeHolder: UIImage?) {

        self.image = nil
        if let cachedImage = imageCache.object(forKey: NSString(string: URLString)) {
            self.image = cachedImage
            return
        }

        if let url = URL(string: URLString) {
            URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in

                //print("RESPONSE FROM API: \(response)")
                if error != nil {
                    print("ERROR LOADING IMAGES FROM URL: \(String(describing: error))")
                    DispatchQueue.main.async { [weak self] in
                        self?.image = placeHolder
                    }
                    return
                }
                DispatchQueue.main.async { [weak self] in
                    if let data = data {
                        if let downloadedImage = UIImage(data: data) {
                            imageCache.setObject(downloadedImage, forKey: NSString(string: URLString))
                            self?.image = downloadedImage
                        }
                    }
                }
            }).resume()
        }
    }
}