class - Apple Swift - 在 arc4random_uniform 中放置一个变量

Question

有一个相当基本的 Swift 问题要问你们。

我的目标:能够在 arc4random 中使用变量(数组中的项目数)。

问题:我不知道如何将“balloonCount”移到 createBalloons() 函数之外。

解决方案？ 在 currentIndex 之上定义“balloonCount”，这样程序就会识别这个变量。 (我被告知这是解决方案，不幸的是我还不知道该怎么做......)

这是我的(更新的)swift 代码:

//
//

import UIKit

class ViewController: UIViewController {
@IBOutlet weak var balloonsLabel: UILabel!
@IBOutlet weak var backgroundImageView: UIImageView!


var balloons:[Balloon] = []

var currentIndex = Int(arc4random_uniform(UInt32(balloons.count)))

“ViewController.type”没有名为“balloons”的成员

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    self.createBalloons()
}

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

@IBAction func nextBalloonBarButtonItemPressed(sender: UIBarButtonItem) {
    let balloon = balloons[currentIndex]

“ViewController”没有名为“currentIndex”的成员

    balloonsLabel.text = "\(balloon.number) Balloon"
    backgroundImageView.image = balloon.image

    currentIndex = currentIndex + 1

“ViewController”没有名为“currentIndex”的成员

    if currentIndex > 99 {

“ViewController”没有名为“currentIndex”的成员 当前索引 = 50

}


func createBalloons () {
    for var balloonCount = 0; balloonCount <= 99; ++balloonCount{

        var balloon = Balloon()


        //I dont think you need a switch here.
        let randomNumber = Int(arc4random_uniform(UInt32(4)))

        let balloonName:String = "redBalloon\(randomNumber).jpg"

        balloon.image = UIImage(named: balloonName)
        balloon.number = balloonCount 

        self.balloons.append(balloon)

    }
}

}

Answer 1

试试这个，但不确定语法是否是 100%。我在这个 comp 上没有 Xcode。让我知道这是否有帮助。另外，如果有人在这里看到任何似乎不对的地方，请在下面发表评论，我会更新我的答案。

试试这个:

var currentIndex = Int(arc4random_uniform(UInt32(balloons.count)))

另外我在这里做了一些修改:

func createBalloons () {
    for var balloonCount = 0; balloonCount <= 99; ++balloonCount{

        var balloon = Balloon()


    //I dont think you need a switch here.
    let randomNumber = Int(arc4random_uniform(UInt32(4)))

    let balloonName:String = "redBalloon\(randomNumber).jpg"

    balloon.image = UIImage(named: balloonName)
    balloon.number = balloonCount 

    self.balloons.append(balloon)

    }
}