ios - 动画后不显示图像

Question

我正在尝试触发动画，当动画完成时，我希望图像保留在正在运行动画的 UIImageView 中。

但是，除非我运行动画两次，否则图像不会显示在 View 中。这是我的代码:

@IBAction func selfRightButton(sender: UIButton){
    Visuals.endgameAnimation(winLoseAnimationView, animationFlow: "win");
    winLoseAnimationView.image = UIImage(named: "win_00012.png");
}

这是 endgameAnimation 方法的代码:

static func endgameAnimation(animationImage: UIImageView, animationFlow: String){
    var counter : Int?;
    var duration : Double?;
    var animationFlowImagePrefix : String?;
    var imageList = [UIImage]();

    if (animationFlow == "bang"){
        counter = 11;
        animationFlowImagePrefix = "bang_00001_000";
        duration = 0.8;
    }
    if (animationFlow == "confetti"){
        counter = 59;
        animationFlowImagePrefix = "confetti_000";
        duration = 0.8;
    }
    if (animationFlow == "lose"){
        counter = 12;
        animationFlowImagePrefix = "lose_000";
        duration = 0.8;
    }
    if (animationFlow == "win"){
        counter = 12;
        animationFlowImagePrefix = "win_000";
        duration = 0.8;
    }

    var i : Int?;

    for (i = 0; i < counter; ++i!) {
        if (i < 9) {
            animationFlowImagePrefix! += "0";
            animationFlowImagePrefix! += String(i!+1);
        } else {
            animationFlowImagePrefix! += String(i!+1);
        }

        var imageToAppend:UIImage = UIImage(named: animationFlowImagePrefix!)!;

        imageList.append(imageToAppend);
        animationFlowImagePrefix = animationFlowImagePrefix!.substringToIndex(animationFlowImagePrefix!.endIndex.predecessor())
        animationFlowImagePrefix = animationFlowImagePrefix!.substringToIndex(animationFlowImagePrefix!.endIndex.predecessor())
    }

    animationImage.animationImages = imageList;
    animationImage.animationDuration = duration!;
    animationImage.animationRepeatCount = 1;
    animationImage.startAnimating();
}

Answer 1

您似乎认为您的代码按以下顺序运行:

Visuals.endgameAnimation(winLoseAnimationView, animationFlow: "win");
// animation ends
winLoseAnimationView.image = UIImage(named: "win_00012.png");

但事实并非如此。动画需要时间——这就是动画，随着时间的推移而发生的变化。但是您的代码不会在动画期间神奇地暂停:它会继续播放。因此，设置图像的第二行发生在动画甚至有机会开始之前。

如果您希望在动画之后发生某些事情，请在动画的完成处理程序 中进行。这就是它的用途(因此得名)。

(在您的情况下，没有完成处理程序，因为您使用的是 ImageView 动画，但将第二行移动到第一行之前可能就足够了。我不确定 - 您必须尝试一下看看。)