Question

为你们所有人提供了一个相当基本的Swift问题。

我的目标：能够在arc4random中使用变量（数组中的项目数）。

问题：我不知道如何移动＆＃34; balloonCount＆＃34;在createBalloons（）函数之外。

解决方案？定义＆＃34; balloonCount＆＃34;在currentIndex之上，程序将识别此变量。（我被告知这是解决方案，我很遗憾不知道如何做到这一点......）

这是我的（更新的）快速代码：

//
//

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)))

＆＃39; ViewController.type＆＃39;没有名为＆＃39; balloons＆＃39;

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]

＆＃39;的ViewController＆＃39;没有名为＆＃39; currentIndex＆＃39;

的成员

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

    currentIndex = currentIndex + 1

＆＃39;的ViewController＆＃39;没有名为＆＃39; currentIndex＆＃39;

的成员

    if currentIndex > 99 {

＆＃39;的ViewController＆＃39;没有名为＆＃39; currentIndex＆＃39;的成员 currentIndex = 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，不确定语法是否100％。我在这个comp上没有Xcode。如果这有点帮助我，请告诉我。此外，如果有人看到任何看似错误的地方，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)))

我也在这里做了一些改变：

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 2

我认为您不能将函数分配给使用其他实例变量的变量。

我将currentIndex设为Int，然后创建一个单独的getRandomIndex函数。所以代码看起来像这样：

var currentIndex: Int!
func getRandomIndex() -> Int {
    return Int(arc4random_uniform(UInt32(balloons.count)))
}

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

Apple Swift - 在arc4random_uniform中放置一个变量

2 个答案: