removeFromSuperview（）不起作用

Question

我想在touch id被問到的時候模糊背景，一旦授權成功，viewcontroller需要可見。但是這並沒有發生。即使授權成功，viewcontroller仍然模糊不清有人可以幫我解決這個問題嗎？

import UIKit 
import LocalAuthentication 
class TabBarViewController: UITabBarController { 

@IBOutlet weak var noteTabBar: UITabBar! 

override func viewDidLoad() { 
super.viewDidLoad() 
    self.authenticateUser() 
    self.tabBar.hidden = false 
    self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer()) 

    let userDefaults = NSUserDefaults.standardUserDefaults() 
    userDefaults.setObject(false, forKey: "sendModeToggle") 
    userDefaults.setObject("Avenir-Medium", forKey: "font") 
    userDefaults.setObject(13, forKey:"fontSize") 
      // Do any additional setup after loading the view. 
} 
override func didReceiveMemoryWarning() { 
    super.didReceiveMemoryWarning() 
    // Dispose of any resources that can be recreated. 
} 


/* 
// MARK: - Navigation 

// In a storyboard-based application, you will often want to do a little preparation before navigation 
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { 
    // Get the new view controller using segue.destinationViewController. 
    // Pass the selected object to the new view controller. 
} 
*/ 

// MARK: Touch ID Authentication 

func authenticateUser() 
{ 
    let context = LAContext() 
    var error: NSError? 
    let reasonString = "Authentication is needed to access your app! :)" 

    let blurEffect = UIBlurEffect(style: .Light) 
    let blurVisualEffectView = UIVisualEffectView(effect: blurEffect) 
    blurVisualEffectView.frame = view.bounds 
    self.view.addSubview(blurVisualEffectView) 

    if context.canEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, error: &error) 
    { 

     context.evaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, localizedReason: reasonString, reply: { (success, policyError) -> Void in 

      if success 
      { 
       print("Authentication successful! :) ") 
       blurVisualEffectView.removeFromSuperview() 

      } 
      else 
      { 
       switch policyError!.code 
       { 
       case LAError.SystemCancel.rawValue: 
        print("Authentication was cancelled by the system.") 
       /*case LAError.UserCancel.rawValue: 
        print("Authentication was cancelled by the user.") 
       */ 
       case LAError.UserFallback.rawValue: 
        print("User selected to enter password.") 
        NSOperationQueue.mainQueue().addOperationWithBlock({() -> Void in 
         self.showPasswordAlert() 
         blurVisualEffectView.removeFromSuperview() 

        }) 
       default: 
        print("Authentication failed! :(") 
        NSOperationQueue.mainQueue().addOperationWithBlock({() -> Void in 
         self.showPasswordAlert() 
         blurVisualEffectView.removeFromSuperview() 

        }) 
       } 
      } 

     }) 

    } 
    else 
    { 
     print(error?.localizedDescription) 
     NSOperationQueue.mainQueue().addOperationWithBlock({() -> Void in 
      self.showPasswordAlert() 
     }) 
    } 


} 

} 

Answer 1

由於您在閉包中刪除視圖，您可能不在主線程中。儘量派遣移除代碼主線：

if success { 
    print("Authentication successful! :) ") 
    dispatch_async(dispatch_get_main_queue()) { 
     blurVisualEffectView.removeFromSuperview() 
    } 
}