ios - 为什么数据没有被保存？

Question

当我尝试在某个 View Controller 上打开通知时，出现 fatal error :在展开可选值时意外发现 nil。我想我知道为什么，有些变量为 nil，导致应用程序崩溃，但我试图为这些变量提供数据，但它们没有保存。

    func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) {
     PFPush.handlePush(userInfo)
  let text = userInfo["aps"]!["alert"]
    let title = userInfo["aps"]!["alert"]!!["title"]
    let artist = userInfo["aps"]!["alert"]!!["artist"]
    print(text)
    print(title)
    print(artist)

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let vc = storyboard.instantiateViewControllerWithIdentifier("PlayerController") as! PlayerViewController
    vc.dataModel.artistplay = artist as? String
    vc.dataModel.titleplay = title as? String
    window?.rootViewController = vc

    }

这是 PlayerViewController 的代码(我在打开推送通知时尝试打开的 View Controller )

 @IBOutlet weak var playertitle: UILabel!
@IBOutlet weak var playerartist: UILabel!
var dicData : NSDictionary?
var dataModel : DataModelTwo?
var data: NSDictionary?
var shareDataModel: Share?
var buttonState: Int = 0;

 override func viewWillAppear(animated: Bool) {

    playertitle.text = dataModel!.titleplay
    playerartist.text = dataModel!.artistplay

}

Answer 1

不要从 AppDelegate 设置 UILable 文本。在您的 ViewController 中设置一个变量，然后在 viewDidLoad 中使用它。

func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) {
  PFPush.handlePush(userInfo)
  let text = userInfo["aps"]!["alert"]
  print(text)
  let storyboard = UIStoryboard(name: "Main", bundle: nil)
  let vc = storyboard.instantiateViewControllerWithIdentifier("PlayerController") as! PlayerViewController
  vc.foo = "bar"
  window?.rootViewController = vc
}

使用变量和更新 UI :

override func viewDidLoad() {
     print(self.foo) // output is "bar"
}