问题
I\'m creating an app that uses the Facebook SDK to authenticate users. I\'m trying to consolidate the facebook logic in a separate class. Here is the code (stripped for simplicity):
import Foundation
class FBManager {
class func fbSessionStateChane(fbSession:FBSession!, fbSessionState:FBSessionState, error:NSError?){
//... handling all session states
FBRequestConnection.startForMeWithCompletionHandler { (conn: FBRequestConnection!, result: AnyObject!, error: NSError!) -> Void in
println(\"Logged in user: \\n\\(result)\");
let storyboard = UIStoryboard(name: \"Main\", bundle: NSBundle.mainBundle())
let loggedInView: UserViewController = storyboard.instantiateViewControllerWithIdentifier(\"loggedInView\") as UserViewController
loggedInView.result = result;
//todo: segue to the next view???
}
}
}
I\'m using the above class method to check session state changes, and it works fine.
Q: Once I have the user\'s data, how can I segue to the next view from within this custom class?
EDIT: just to be clear, I have a segue with identifier on the storyboard, and I\'m trying to find a way to perform a segue from a class which is not the view controller
回答1:
If your segue exists in the storyboard with a segue identifier between your two views, you can just call it programmatically using:
performSegue(withIdentifier: "mySegueID", sender: nil)
For older versions:
performSegueWithIdentifier("mySegueID", sender: nil)
You could also do:
presentViewController(nextViewController, animated: true, completion: nil)
Or if you are in a Navigation controller:
self.navigationController?.pushViewController(nextViewController, animated: true)
回答2:
You can use NSNotification
Add a post method in your custom class:
NSNotificationCenter.defaultCenter().postNotificationName("NotificationIdentifier", object: nil)
Add an observer in your ViewController:
NSNotificationCenter.defaultCenter().addObserver(self, selector: "methodOFReceivedNotication:", name:"NotificationIdentifier", object: nil)
Add function in you ViewController:
func methodOFReceivedNotication(notification: NSNotification){
self.performSegueWithIdentifier("yourIdentifierInStoryboard", sender: self)
}
回答3:
You can use segue like this:
self.performSegueWithIdentifier("push", sender: self)
override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
if segue.identifier == "push" {
}
}
回答4:
If your segue exists in the storyboard with a segue identifier between your two views, you can just call it programmatically using
self.performSegueWithIdentifier("yourIdentifierInStoryboard", sender: self)
If you are in Navigation controller
let viewController = YourViewController(nibName: "YourViewController", bundle: nil)
self.navigationController?.pushViewController(viewController, animated: true)
I will recommend you for second approach using navigation controller.
回答5:
Swift 3 - Also works with SpriteKit
You can use NSNotification.
Example:
1.) Create a segue in the storyboard and name the identifier "segue"
2.) Create a function in the ViewController you are segueing from.
func goToDifferentView() {
self.performSegue(withIdentifier: "segue", sender: self)
}
3.) In the ViewDidLoad() of your ViewController you are segueing from create the observer.
NotificationCenter.default.addObserver(self, selector: #selector(goToDifferentView), name: "segue" as NSNotification.Name, object: nil)
Update -
Last time I used this I had to change the .addObserver call to the following code to silence the errors.
NotificationCenter.default.addObserver(self, selector: #selector(goToDifferentView), name: NSNotification.Name(rawValue: "segue"), object: nil)
4.) In the ViewController or Scene you are segueing to, add the Post Method wherever you want the segue to be triggered.
NotificationCenter.default.post(name: "segue" as NSNotification.Name, object: nil)
Update -
Last time I used this I had to change the .post call to the following code to silence the errors.
NotificationCenter.default.post(NSNotification(name: NSNotification.Name(rawValue: "segue"), object: nil) as Notification)
回答6:
What you want to do is really important for unit testing. Basically you need to create a small local function in the view controller. Name the function anything, just include the performSegueWithIndentifier.
func localFunc() {
println("we asked you to do it")
performSegueWithIdentifier("doIt", sender: self)
}
Next change your utility class FBManager to include an initializer that takes an argument of a function and a variable to hold the ViewController's function that performs the segue.
public class UtilClass {
var yourFunction : () -> ()
init (someFunction: () -> ()) {
self.yourFunction = someFunction
println("initialized UtilClass")
}
public convenience init() {
func dummyLog () -> () {
println("no action passed")
}
self.init(dummyLog)
}
public func doThatThing() -> () {
// the facebook login function
println("now execute passed function")
self.yourFunction()
println("did that thing")
}
}
(The convenience init allows you to use this in unit testing without executing the segue.)
Finally, where you have //todo: segue to the next view???, put something along the lines of:
self.yourFunction()
In your unit tests, you can simply invoke it as:
let f = UtilClass()
f.doThatThing()
where doThatThing is your fbsessionstatechange and UtilClass is FBManager.
For your actual code, just pass localFunc (no parenthesis) to the FBManager class.
回答7:
This worked for me.
First of all give the view controller in your storyboard a Storyboard ID inside the identity inspector. Then use the following example code (ensuring the class, storyboard name and story board ID match those that you are using):
let viewController:
UIViewController = UIStoryboard(
name: "Main", bundle: nil
).instantiateViewControllerWithIdentifier("ViewController") as UIViewController
// .instantiatViewControllerWithIdentifier() returns AnyObject!
// this must be downcast to utilize it
self.presentViewController(viewController, animated: false, completion: nil)
For more details see http://sketchytech.blogspot.com/2012/11/instantiate-view-controller-using.html best wishes
回答8:
You can do this thing using performSegueWithIdentifier function.
Syntax :
func performSegueWithIdentifier(identifier: String, sender: AnyObject?)
Example :
performSegueWithIdentifier("homeScreenVC", sender: nil)
回答9:
Another option is to use modal segue
STEP 1: Go to the storyboard, and give the View Controller a Storyboard ID. You can find where to change the storyboard ID in the Identity Inspector on the right.
Lets call the storyboard ID ModalViewController
STEP 2: Open up the 'sender' view controller (let's call it ViewController) and add this code to it
public class ViewController {
override func viewDidLoad() {
showModalView()
}
func showModalView() {
if let mvc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ModalViewController") as? ModalViewController {
self.present(mvc, animated: true, completion: nil)
}
}
}
Note that the View Controller we want to open is also called ModalViewController
STEP 3: To close ModalViewController, add this to it
public class ModalViewController {
@IBAction func closeThisViewController(_ sender: Any?) {
self.presentingViewController?.dismiss(animated: true, completion: nil)
}
}
来源：https://stackoverflow.com/questions/27604192/ios-how-to-segue-programmatically-using-swift