swift - 如何在用户单击按钮时使图像更改几秒钟，然后 swift 恢复为原始图像？

Question

大家好，我是 Swift 编码的新手，也是 Stackoverflow 的新手。如何制作一个按钮，该按钮会更改图像约 5 秒，然后在用户点击该按钮时返回到原始图像？

我试过使用这段代码

       dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (Int64)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), {
           gauntletImage.image = UIImage(named: gauntlet["gauntlet2"]) //change back to the old image after 5 sec
       });

但我不断收到这两个错误:

无法将“Int”类型的值转换为预期的参数类型“dispatch_time_t”(又名“UInt64”)

和

“dispatch_get_main_queue()”的使用不明确

这是我正在使用的更多代码。

@IBOutlet weak var gauntletImage: UIImageView!

    let gauntlet = ["gauntlet1", "gauntlet2", "gauntlet3", "gauntlet4", "gauntlet5", "gauntlet6",]


    @IBAction func stonePressed(_ sender: UIButton) {
        print(sender.tag)

        gauntletImage.image = UIImage(named: gauntlet[sender.tag - 1]) //change to the new image

        dispatch_after(dispatch_time(dispatch_time_t(DISPATCH_TIME_NOW), (Int64)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), {
            gauntletImage.image = UIImage(named: gauntlet["gauntlet2"]) //change back to the old image after 5 sec
        });
    }

Answer 1

你可以试试

@IBAction func stonePressed(_ sender: UIButton) { 
    // store old image assuming it has an initial image in storyboard
    let oldImg = gauntletImage.image!
    // set new image
    gauntletImage.image = UIImage(named: gauntlet[sender.tag - 1])  
    // wait 5 seconds 
    DispatchQueue.main.asyncAfter(deadline: .now() + 5 ) { 
        // set back old image
        self.gauntletImage.image = oldImg   
   }   

}

用户可能会多次点击它，所以你也可以这样做

sender.isEnabled = false

当存储旧图像并将其设置回 true block 后调度