根据 Swift Xcode 中的变量将 UI 图像更改为特定图像

Question

我想根据变量更改图像，我不确定该怎么做。

我认为我的代码是正确的，但是在 iOS 模拟器中，图像显示为空白。我想知道为什么？

下面是我的代码：

import UIKit

class BuyTicketViewController: UIViewController {

@IBOutlet weak var stadiumImage: UIImageView!
@IBOutlet weak var logoImage: UIImageView!

override func viewDidLoad() {
    super.viewDidLoad()

    if (globalVenueSelected == "Gillingham Football Club"){
        let imageGillinghmaFootballClub : UIImage = UIImage(named: "gillinghamStadium.jpg")!
        let stadiumImage = (image: imageGillinghmaFootballClub)

    }
    if (globalVenueSelected == "Old Trafford"){
        let imageOldTraffordFootballClub : UIImage = UIImage(named: "oldTraffordStadium.jpg")!
        let stadiumImage = (image: imageOldTraffordFootballClub)

    }
    if (globalVenueSelected == "Emirates Stadium"){
        let imageEmiratesFootballClub : UIImage = UIImage(named: "emiratesStadium.jpg")!
        let stadiumImage = (image: imageEmiratesFootballClub)

    }
    if (globalVenueSelected == "Wembley"){
        let imageWembley : UIImage = UIImage(named: "wemblyStadium.jpg")!
        let stadiumImage = (image: imageWembley)

    }
    if (globalVenueSelected == "O2 Arena"){
        let imageO2Arena : UIImage = UIImage(named: "o2ArenaStadium.jpg")!
        let stadiumImage = (image: imageO2Arena)
    }



}

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


/*
// MARK: - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    // Pass the selected object to the new view controller.
}
*/


}

哦，顺便说一下，变量 globalVenueSelected 是一个全局变量，我不知道它是否会影响任何东西，但它可能会更改代码。

感谢任何帮助，谢谢。

Answer 1

试试下面的代码。

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    var imageName: String!

    switch globalVenueSelected {
    case "Gillingham Football Club":
        imageName = "gillinghamStadium.jpg"

    case "Old Trafford":
        imageName = "oldTraffordStadium.jpg"

    case "Emirates Stadium":
        imageName = "emiratesStadium.jpg"

    case "Wembley":
        imageName = "wemblyStadium.jpg"

    case "O2 Arena":
        imageName = "o2ArenaStadium.jpg"

    default: break
    }

    self.stadiumImage.image = UIImage(named: imageName)
}

您应该将 switch 语句放在 viewWillAppear(:) 中，因为您的 IBOutlet 可能未在 viewDidLoad 中设置。

另外，许多人认为最好的做法是使用反映该变量类型的变量名。例如，

stadiumImage 应重命名为 stadiumImageView.
同样，logoImage 应重命名为 logoImageView。

正确命名您的变量名将使您和其他人更容易阅读、理解和维护您的代码。

此外，默认情况下，项目的资产目录通常不接受 .jpg 文件。您可以将体育场图像转换为 .png 格式，然后在设计时将它们添加到您的资产目录中，或者您可以参考 this Stack Overflow answer 了解如何让您的资产目录接受非 PNG 资产。

根据 Swift Xcode 中的变量将 UI 图像更改为特定图像

Changing UI Image to a specific image depending on variable in Swift Xcode

xcode

uiimageview

uiimage

ios

swift