小编vyu*_*udi的帖子

我有这个drawRandomCard函数的问题.

它的工作方式就像它应该存在一段时间,但最终它会崩溃应用程序.

这是代码:

import Foundation


var cardDeck = Array<PlayingCard>()

class Deck {

    func addCard(card : PlayingCard , atTop : Bool = false){

        if atTop {
            cardDeck.insert(card, atIndex: 0);
        }else{
            cardDeck += card
        }
    }

    func drawRandomCard() -> PlayingCard{
        var card = PlayingCard()
        var randomNumber : Int = Int(arc4random()) % (cardDeck.count - 1)
        card = cardDeck[randomNumber]
        cardDeck.removeAtIndex(randomNumber)
        return card
    }

}

突然,我在Apple的文档中学到的for循环结构停止了工作,它显示了一个错误:预期的声明.谁能告诉我新的语法是什么？

let CirclePoints = 84

var circlePoint = 0

for circlePoint in 0..<CirclePoints {

}

这种方式也行不通:

for var circlePoint = 0; circlePoint < CirclePoints; circlePoint++ {

}

我收到此错误:无法将表达式的类型'()转换为从Card输入$'T5'PlayardCard继承,我知道drawRandomCard返回一个PlayingCard.我怎样才能进行这种转换？

var deck = PlayingCardDeck()
var card = PlayingCard()

class ViewController: UIViewController {



override func viewDidLoad() {
    super.viewDidLoad()

}

@IBAction func cardTouchBtn(sender : UIButton) {

    if !sender.currentTitle{sender.setTitle("", forState: UIControlState.Normal)}
    if  sender.currentTitle.isEmpty{
        card = PlayingCard(deck.drawRandomCard())
        sender.setBackgroundImage(UIImage(named : "cardFront"), forState: UIControlState.Normal)
        sender.setTitle(card.contents, forState: UIControlState.Normal)
    }else{
        sender.setBackgroundImage(UIImage(named : "cardBack"), forState: UIControlState.Normal)
        sender.setTitle("", forState: UIControlState.Normal)
    }
}

}

关于git的完整代码:https://github.com/victoryudi/CS193p-Swift/tree/master/FlipCard