从WatchKit上的URL加载图像 [英] Load image from URL on WatchKit

问题描述

在手表上加载外部图像是否比以下更优雅的解决方案?

Is there a more elegant solution to load an external image on the watch than the following ?

let image_url:String = "http://placehold.it/350x150"

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {
    let url:NSURL = NSURL(string:image_url)!
    var data:NSData = NSData(contentsOfURL: url)!
    var placeholder = UIImage(data: data)!

    // update ui
    dispatch_async(dispatch_get_main_queue()) {
        self.imageView.setImage(placeholder)
    }
}

推荐答案

NSURL用于本地文件.而是使用NSURLSession.设置远程图像的比例也很有用.

NSURL is meant to be used for local files. Instead use NSURLSession. It's also useful to set the scale for the remote image.

import WatchKit

public extension WKInterfaceImage {

    public func setImageWithUrl(url:String, scale: CGFloat = 1.0) -> WKInterfaceImage? {

        NSURLSession.sharedSession().dataTaskWithURL(NSURL(string: url)!) { data, response, error in
            if (data != nil && error == nil) {
                let image = UIImage(data: data!, scale: scale)

                dispatch_async(dispatch_get_main_queue()) {
                    self.setImage(image)
                }
            }
        }.resume()

        return self
    }
}

像这样使用它

self.imageView.setImageWithUrl(image_url, scale: 2.0)

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