无法将“NSData”类型的值转换为预期的参数类型“字符串”答案

【问题标题】：Cannot convert value of type 'NSData' to expected argument type 'String'无法将“NSData”类型的值转换为预期的参数类型“字符串”
【发布时间】：2016-06-01 12:39:07
【问题描述】：

我正在 XCode 中快速编写代码。这是代码：

import UIKit
import Foundation

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        let notificationTypes : UIUserNotificationType = [.Alert, .Badge, .Sound]
        let notificationSettings : UIUserNotificationSettings = UIUserNotificationSettings(forTypes: notificationTypes, categories: nil)
        UIApplication.sharedApplication().registerUserNotificationSettings(notificationSettings)

        return true
    }

    func application(application: UIApplication, didRegisterUserNotificationSettings notificationSettings: UIUserNotificationSettings)
    {
        UIApplication.sharedApplication().registerForRemoteNotifications()
    }

    func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {

        print("TOKEN:", deviceToken);

        let token = String(data: deviceToken, encoding: NSUTF8StringEncoding);
        let myUrl = NSURL(fileURLWithPath: "http://......php?id=" + token);

        print("URL:",fileURLWithPath: "http://......php?id=" + token);

    }


    func application(application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: NSError) {
        print(error.localizedDescription)
    }

  /*  func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) {

    }*/


    func applicationWillResignActive(application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
    }

    func applicationDidEnterBackground(application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }

    func applicationWillEnterForeground(application: UIApplication) {
        // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
    }

    func applicationDidBecomeActive(application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }

    func applicationWillTerminate(application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }


}

编译器在 func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {" 上给我一个错误，它说我 "Cannot convert value of type 'NSData' to expected argument type 'String'"...但我无法理解解决问题的方法。所以，有人可以帮我纠正错误？

【问题讨论】：

打印token的结果是什么
这是结果“致命错误：在展开可选值 (lldb) 时意外发现 nil”另一个错误
@MatteoRK22 你需要解开可选值 - 看看我的回答

标签： xcode string swift nsdata

【解决方案1】：

var charSet: NSCharacterSet = NSCharacterSet(charactersInString: "<>")
var tokenStr: String = (deviceToken.description as NSString)
            .stringByTrimmingCharactersInSet(characterSet)
            .stringByReplacingOccurrencesOfString( " ", withString: "") as String

print(deviceTokenString)

试试看

【讨论】：

你的答案比我早9秒哈哈

【解决方案2】：

使用它来向服务器发送令牌。对我来说效果很好

    var token: String = "\(deviceToken)"
    let rawtoken = token.stringByReplacingOccurrencesOfString(">", withString: "")
    let cleantoken = rawtoken.stringByReplacingOccurrencesOfString("<", withString: "")
    var finaltoken = cleantoken.stringByReplacingOccurrencesOfString(" ", withString: "")

最终令牌是您应该使用的令牌。

来源是 Udemy 在线课程。

【讨论】：

【解决方案3】：

请注意，令牌是 BINARY，因此您不能轻松地将其转换为字符串（不是 UTF8！）。将其转换为十六进制是一个好习惯：

let tokenChars = UnsafePointer<CChar>(deviceToken.bytes)
var tokenString = ""

for var i = 0; i < deviceToken.length; i++ {
    tokenString += String(format: "%02.2hhx", arguments: [tokenChars[i]])
}

print("Push token: \(tokenString)")

【讨论】：