參數是一個未聲明的類型？

Question

我想設置一個函數中的參數，但控制檯說明

使用未申報類型rightAnimation

func slideFromRight(from: rightInAnimation.fromValue = 25) { 

    let rightInAnimation = CABasicAnimation(keyPath: "transform.translation.x") 
    rightInAnimation.duration = 0.5 
    rightInAnimation.fromValue = 25 
    rightInAnimation.toValue = 0 
    rightInAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) 

    self.layer.add(rightInAnimation, forKey: "animateTranslation") 
} 

我很困惑的。我認爲我不需要在頂層聲明這一點。目的是在分配時能夠更改fromValue。

Answer 1

的問題是用下面的代碼：

func slideFromRight(from: rightInAnimation.fromValue = 25) 

您需要更改到：

func slideFromRight(from : Int = 25) 
{ 
    let rightInAnimation   = CABasicAnimation(keyPath: "transform.translation.x") 
    rightInAnimation.duration  = 0.5 
    rightInAnimation.fromValue  = from 
    rightInAnimation.toValue  = 0 
    rightInAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) 

    self.layer.add(rightInAnimation, forKey: "animateTranslation") 
}