ios - 代码将在 Playground 上运行，但在应用程序模拟器中执行时失败

Question

我正在尝试使用 NSURL 函数获取 URL 的 HTML。代码运行良好，并且在从 Playground 执行时正确返回 HTML，但是当我将其实现为 Storyboard中的按钮时，应用程序崩溃了。我更改了 Info.plist 文件中的应用程序传输安全性，但仍然遇到崩溃。这是我的 Info.plist:http://imgur.com/a/BB3KF 。错误消息还说有一个 nil 值，但是我测试了函数中的变量，一切似乎都是 != nil。

Playground 代码:

let myUrl = NSURL(string: "http://www.google.com")
        let request = NSMutableURLRequest(URL: myUrl!)
        request.HTTPMethod = "POST"
        let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
            data, response, error in
            let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding)
            self.testLabel.text = "\(responseString)"
            if error != nil {
                print("Error: \(error)")
            }
        }
        task.resume()

XCode 代码:

import UIKit
import Foundation

class ViewController: UIViewController {

    @IBOutlet weak var testLabel: UILabel!

    @IBAction func testButton(sender: UIButton) {
        let myUrl = NSURL(string: "http://www.google.com")
        let request = NSMutableURLRequest(URL: myUrl!)
        request.HTTPMethod = "POST"
        let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
            data, response, error in
            let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding)
            self.testLabel.text = "\(responseString)"
            if error != nil {
                print("Error: \(error)")
            }
        }
        task.resume()
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

}

错误消息:

2015-10-29 10:20:36.127 testProject[1263:49414] App Transport Security has blocked a cleartext HTTP (http://) resource load since it is insecure. Temporary exceptions can be configured via your app's Info.plist file. fatal error: unexpectedly found nil while unwrapping an Optional value (lldb)

Answer 1

出现此错误是因为 iOS9 与服务器的连接必须是安全的 (https ) 才能允许使用 http 将以下内容添加到 info.plist

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>