Question

我的应用程序中有一个带有图像的UIButton。

我希望能够调用一个闪烁该按钮多次的功能（比如说5次）
我也希望能够在运行时停止闪烁

以下是代码的重要部分：

var flashesRemaining: Int = 5;
var isFlashing: Bool = false

@IBOutlet weak var btnMM: UIButton!

// Flash the button
@IBAction func flashMemoryButton(sender: AnyObject) {
    print(self.flashesRemaining)
    if self.flashesRemaining == 0 {
        return
    }
    if !isFlashing {
        self.btnMM.alpha = 1.0
        UIView.animate(withDuration: 0.5, delay: 0.0, options: [.curveEaseInOut, .repeat, .autoreverse, .allowUserInteraction], animations: {() -> Void in
            self.btnMM.alpha = 0.0100000003
        }, completion: {(finished: Bool) -> Void in })

        isFlashing = true
    }
    else {
        UIView.animate(withDuration: 0.1, delay: 0.0, options: [.curveEaseInOut, .beginFromCurrentState], animations: {() -> Void in
            self.btnMM.alpha = 1.0
        }, completion: {(finished: Bool) -> Void in })
    }
    self.flashesRemaining = self.flashesRemaining - 1
}

所以我希望能够像这样调用上面的函数，开始闪烁：

self.flashesRemaining = 5
self.flashMemoryButton(sender: self.btnMM)

然后如果我想禁用闪烁，我应该调用：

self.flashesRemaining = 0

但是上面的代码根本不起作用。一旦我打电话

self.flashMemoryButton(sender: self.btnMM)

我打印输出 5 ，然后按钮一直闪烁。我在这里缺少什么？

顺便说一句，神奇的数字0.0100 ... 3是UIButton允许的最小alpha值，同时保持用户的交互性。

Answer 1

这是工作代码：

func flashMemoryButton() {
    print(self.flashesRemaining)
    if self.flashesRemaining == 0 {
        btnMM.alpha = 1
        return
    }
    if !isFlashing {
        self.btnMM.alpha = 1.0
        UIView.animate(withDuration: 0.5, delay: 0.0, options: [.curveEaseInOut, .allowUserInteraction], animations: {() -> Void in
            self.btnMM.alpha = 0.0100000003
        }, completion: {(finished: Bool) -> Void in
            if finished {
                self.flashMemoryButton()
                self.flashesRemaining = self.flashesRemaining - 1
            }
        })

        isFlashing = true
    }
    else {
        UIView.animate(withDuration: 0.1, delay: 0.0, options: [.curveEaseInOut, .beginFromCurrentState], animations: {() -> Void in
            self.btnMM.alpha = 1.0
        }, completion: {(finished: Bool) -> Void in
            if finished {
                self.flashMemoryButton()

            }
        })
        isFlashing = false
    }
}

以下是我所做的更改：

首先，我删除了.repeat和.autoreverse。这是因为我们希望多次调用flashMemoryButton方法而不是重复动画。

接下来，我在isFlashing = false分支中添加了else。这样，当isFlashing为真时，按钮会在下次调用方法时淡出，而当isFlashing为假时，按钮会淡出。您可以将isFlashing视为切换。

当淡入/淡出动画完成时，我调用flashMemoryButton()，因为当动画结束时，你想要做另一个动画，对吗？

在淡出动画的完成处理程序中，我减少了flashesRemaining。这是您想要减少它的地方，而不是在if语句之外。如果你把它放在外面，它会闪现你告诉它的一半时间。

Answer 2

您可以使用UIView.setAnimationRepeatCount;因此你不再需要flashesRemaining了。您还应该在完成处理程序中重新设置isFlashing - 标志。这是我修改过的代码：

var isFlashing: Bool = false

@IBOutlet weak var btnMM: UIButton!

@IBAction func flashMemoryButton(sender: AnyObject) {
    if !isFlashing {
        self.btnMM.alpha = 1.0
        UIView.animate(withDuration: 0.5, delay: 0.0, options: [.curveEaseInOut, .repeat, .autoreverse, .allowUserInteraction], animations: {() -> Void in
            UIView.setAnimationRepeatCount(5)
            self.btnMM.alpha = 0.0100000003
        }, completion: {(finished: Bool) -> Void in
            UIView.animate(withDuration: 0.1, delay: 0.0, options: [.curveEaseInOut, .beginFromCurrentState], animations: {() -> Void in
                self.btnMM.alpha = 1.0
            }, completion: {(finished: Bool) -> Void in self.isFlashing = false})
        })

        isFlashing = true
    }
    else {
        UIView.animate(withDuration: 0.1, delay: 0.0, options: [.curveEaseInOut, .beginFromCurrentState], animations: {() -> Void in
            self.btnMM.alpha = 1.0
        }, completion: {(finished: Bool) -> Void in self.isFlashing = false})
    }
}

在流上动画UIButton

2 个答案: