如何在swift中将数组转换为另一个视图控制器？

Question

I am trying to segue an array filled with Strings from the FactsViewController to the FavoritesViewController, but for some reason when I add some elements to the array, run the code, and transfer to the FavoritesViewController it says there are no elements in the array...

First View Controller:

import UIKit

class FactsViewController: UIViewController {

@IBOutlet var factsLabel: UILabel!
@IBOutlet var nextButton: UIButton!
@IBOutlet var previousButton: UIButton!
@IBOutlet var favoriteButton: UIButton!
var factNumber: Int = 0
var i = 0
var favoriteFactsList: [String] = []
var factsList: [String] = ["Fact 1", "Fact 2", "Fact 3", "Fact 4"]

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    factsLabel?.text = factsList[factNumber]
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

// Segue array to Favorites ViewController
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    var destinationViewController: FavoritesViewController = segue.destinationViewController as FavoritesViewController
    var arrayToSegue: [String] = favoriteFactsList
    destinationViewController.favoriteList = arrayToSegue
}

// Next Button
@IBAction func nextButton(UIButton: AnyObject) {
    factNumber++

    if(factNumber >= factsList.count - 1) {
        factNumber = factsList.count - 1
    }

    factsLabel.text = factsList[factNumber]
}

// Previous Button
@IBAction func previousButton(UIButton: AnyObject) {
    factNumber--

    if(factNumber <= 0) {
        factNumber = 0
    }

    factsLabel.text = factsList[factNumber]
}

// Favorite Button
@IBAction func favoriteButton(UIButton: AnyObject) {
    favoriteFactsList.append("\(factsList[factNumber])")
    NSLog(String(favoriteFactsList.count))
}

// Present Favorites ViewController
@IBAction func favoritesViewController(UIButton: AnyObject) {
    let favoritesViewController = self.storyboard?.instantiateViewControllerWithIdentifier("favoritesStoryBoard") as FavoritesViewController
    self.presentViewController(favoritesViewController, animated: true, completion: nil)
}

}

Second View Controller:

import UIKit

class FavoritesViewController: FactsViewController {

@IBOutlet var favoriteFactsLabel: UILabel!
@IBOutlet var favoriteNextButton: UIButton!
@IBOutlet var favoritePreviousButton: UIButton!

var favoriteList: [String] = [String]()
var favoriteFactNumber: Int = 0

override func viewDidLoad() {
    super.viewDidLoad()
    factsList = favoriteFactsList

    NSLog("\(favoriteFactsList.count)")

    if(favoriteList.count == 0) {
        favoriteFactsLabel.text = "Sorry, You Have Not Favorited Any Facts Yet"
        favoriteNextButton.hidden = true
        favoritePreviousButton.hidden = true
    }
}

@IBAction func favoriteNextButton(UIButton: AnyObject) {
    favoriteFactNumber++

    if(favoriteFactNumber >= favoriteList.count - 1) {
        favoriteFactNumber = favoriteList.count - 1
    }

    favoriteFactsLabel.text = favoriteList[favoriteFactNumber]
}

@IBAction func favoritePreviousButton(UIButton: AnyObject) {
    favoriteFactNumber--

    if(favoriteFactNumber <= 0) {
        favoriteFactNumber = 0
    }

    favoriteFactsLabel.text = favoriteList[favoriteFactNumber]
}

override func favoriteButton(UIButton: AnyObject) {
    favoriteList.append("\(factsList[factNumber])")
}

@IBAction func returnButton(UIButton: AnyObject) {
    let factsViewController = self.storyboard?.instantiateViewControllerWithIdentifier("factsStoryBoard") as FactsViewController
    self.presentViewController(factsViewController, animated: true, completion: nil)
}

}

Why will my facts array not segue from the FactsViewController to the FavoritesViewController ?

Answer 1

Your error lies in the method you're using to present FavoritesViewController . You are currently presenting the ViewController via presentViewController() , not a segue, so the method will never be called. You can make a segue from FactsViewController to FavoritesViewController , with a segue identifier. You could possibly call it goToFavoritesView .

// Present Favorites ViewController
@IBAction func favoritesViewController(UIButton: AnyObject) {
    self.performSegueWithIdentifier("goToFavoritesView", sender: self)
}