如何在不使用第三方库的情况下在 swift2 中下载页面？

Question

我正在尝试在应用程序中显示下载的 HTML 页面。 请解释不使用任何第三方库的最简单方法。

干杯，

Answer 1

无需下载即可在应用中显示 html 页面

 let pageUrl = NSURL (string: "http://www.stackoverflow.com");
 let req = NSURLRequest(URL: url!);

如果你想显示一个本地文件，你可以这样显示

let htmlfilePath = NSBundle.mainBundle().URLForResource("filename", withExtension: "html");
    let req = NSURLRequest(URL: htmlfilePath !);
    webview.loadRequest(req);

下载一个文件，你可以使用普通的 NSURLSession

Answer 2

您应该使用 NSURLSession dataTaskWithURL 异步下载您的网站数据：

import UIKit

class ViewController: UIViewController {

    let stackoverflowLink = "https://stackoverflow.com/questions/36315798/how-to-download-a-page-in-swift2-without-using-third-party-libraries"

    override func viewDidLoad() {
        super.viewDidLoad()
        guard let url = NSURL(string: stackoverflowLink) else  { return }
        print("LOADING URL")
        NSURLSession.sharedSession().dataTaskWithURL(url) { (data, response, error) -> Void in
            guard
                let httpURLResponse = response as? NSHTTPURLResponse where httpURLResponse.statusCode == 200,
                let data = data where error == nil,
                let htmlCode = String(data: data, encoding: NSUTF8StringEncoding) // make sure you use the correct String Encoding
            else { return }
            print( htmlCode)
            print("URL LOADED")
        }.resume()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

Answer 3

你可以直接下载一个网站到一个 NSData 对象中，就像这个例子（Objective-C）一样；

    NSURL *tutorialsUrl = [NSURL URLWithString:@"http://www.raywenderlich.com/tutorials"];
    NSData *tutorialsHtmlData = [NSData dataWithContentsOfURL:tutorialsUrl];

Swift 示例；

    let aString = "http://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xfp1/t31.0-8/q88/s720x720/10848858_907722502601079_2834541930671169073_o.jpg"
    let url = NSURL(string: aString)
    let data = NSData(contentsOfURL: url!)

Ray 在这里有一个很棒的教程；

https://www.raywenderlich.com/14172/how-to-parse-html-on-ios