remove index from array with UIImage

问题:

Everything works well except on the last element of the array, I get fatal error: Array index out of range when I click on SnapButton. I tried to add:

//var indexA = getRandomIntFromArray(cardNamesArray)
//var indexB = getRandomIntFromArray(cardNamesArray2)

but I get cannot be used on type View Controller not sure what this means

var firstRandomNumber = Int()
var secondRandomNumber = Int()

class ViewController: UIViewController {

@IBOutlet weak var FirstCardImageView: UIImageView!
@IBOutlet weak var SecondCardImageView: UIImageView!
@IBOutlet weak var PlayRoundButton: UIButton!
@IBOutlet weak var BackgroundImageView: UIImageView!
@IBOutlet weak var playerScoreLabel: UILabel!

var playerScore: Int = 0

var cardNamesArray = ["acorn", "angry","apple", "rainbow", "sad","boots", "heart", "pumpkin","chestnuts"]
var cardNamesArray2 = ["bellota", "enfadado","manzana", "arcoiris","triste","botas","corazon", "calabaza", "castana"]

  override func viewDidLoad() {

   super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

}


override func didReceiveMemoryWarning() {

    super.didReceiveMemoryWarning()

    // Dispose of any resources that can be recreated.

}

@IBAction func playRoundTapped(sender: UIButton) {


    firstRandomNumber = GKRandomSource.sharedRandom().nextIntWithUpperBound(cardNamesArray.count)
    FirstCardImageView.image = UIImage(named: cardNamesArray[firstRandomNumber])

    secondRandomNumber = GKRandomSource.sharedRandom().nextIntWithUpperBound(cardNamesArray2.count)
    SecondCardImageView.image = UIImage(named: cardNamesArray2[secondRandomNumber])


}

    func getRandomIntFromArray(array: [String]) -> Int  {

        return GKRandomSource.sharedRandom().nextIntWithUpperBound(cardNamesArray.count)

    }

//var indexA = getRandomIntFromArray(cardNamesArray)
//var indexB = getRandomIntFromArray(cardNamesArray2)



@IBAction func SnapButtonTapped(sender: UIButton) {
    if cardNamesArray.count > 0 {

        if firstRandomNumber == secondRandomNumber {

            cardNamesArray.removeAtIndex(firstRandomNumber)
            cardNamesArray2.removeAtIndex(secondRandomNumber)

            firstRandomNumber = getRandomIntFromArray(cardNamesArray)
            secondRandomNumber = getRandomIntFromArray(cardNamesArray2)


            //on the last element of the array when I click on SnapButtonTapped I get fatal error: Array index out of range
            FirstCardImageView.image = UIImage(named: cardNamesArray[firstRandomNumber])
            SecondCardImageView.image = UIImage(named: cardNamesArray2[secondRandomNumber])
            print(cardNamesArray)


    } else  {
                print("no cards in array")

        }

    }

}

}

回答1:

You can run this on Playground to understand the logic.

import UIKit
import GameKit

var array1 = ["one", "two"]
var array2 = ["one", "two"]

// Create a helper method to get random int
func getRandomIntFromArray(array: [String]) -> Int {
    return GKRandomSource.sharedRandom().nextIntWithUpperBound(array1.count)
}

var indexA = getRandomIntFromArray(array1)
var indexB = getRandomIntFromArray(array2)

// At snapButtonTapped
// Check the array count first so that you will not get index out of range.
if array1.count > 0 {
    if indexA == indexB {

        // First remove index first
        array1.removeAtIndex(indexA)
        array2.removeAtIndex(indexB)

        // Assign to new random index
        indexA = getRandomIntFromArray(array1)
        indexB = getRandomIntFromArray(array2)

        // After assigned a new random index, set image base on that index
        // FirstCardImageView.image = UIImage(named: array1[indexA])
        // SecondCardImageView.image = UIImage(named: array2[indexB])
    }
} else {
    print("Finished, all array was removed") // Do anything here such as set empty image for FirstCardImageView & SecondCardImageView or success alert.
}

回答2:

You want to remove the images from the cards?

If the answer is yes, just change the card's image to something else:

if firstRandomNumber == secondRandomNumber {
        //print("index match")
        //self.playRoundTapped(self.PlayRoundButton) <--- I have tried to recall the playRoundTapped method but it doesn't remove the element and goes crazy

            cardNamesArray.removeAtIndex(firstRandomNumber)<----how can I apply this to a UIImage?
            cardNamesArray2.removeAtIndex(secondRandomNumber)
            FirstCardImageView.image = UIImage(named: "someDefaultImage")
            SecondCardImageView.image = UIImage(named: "someDefaultImage")
        } 

回答3:

It appears your array is tracking strings, not images.

This line

 SecondCardImageView.image = UIImage(named: secondCardString)

Is creating an image based on the String, which isn't associated or connected the String reference.

If you want to manage the images you need to keep an array of images not strings.

Alternately you could use a Dictionary Swift Collection Types