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将函数传递给完成处理程序

completionhandler swift ios

2

Turnip Moushumi Ahmed · 技术社区 · 7 年前

我有一个在视图上执行动画的函数。我想为这个函数实现一个完成处理程序,它将在动画完成后调用。

在ViewController中。。。

hudView.hide(animated: true, myCompletionHandler: {
    // Animation is complete
})

在HudView类中。。。

func hide(animated: Bool, myCompletionHandler: () -> Void) {
    if animated {
        transform = CGAffineTransform(scaleX: 0.7, y: 0.7)

        UIView.animate(withDuration: 0.3, delay: 0, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.5, options: [], animations: {
            self.alpha = 0
            self.transform = CGAffineTransform.identity
        }, completion: nil) // I want to run 'myCompletionHandler' in this completion handler
    }
}

我尝试了很多方法,但找不到正确的语法:

}, completion: myCompletionHandler)

将非转义参数“myCompletionHandler”传递给需要

}, completion: myCompletionHandler())

无法将“Void”类型的值转换为预期的参数类型((Bool) -&燃气轮机;无效)?”

}, completion: { myCompletionHandler() })

闭包使用非转义参数“myCompletionHandler”可能允许它逃跑

作为一个敏捷的新手,这些错误消息对我来说意义不大,我似乎找不到任何正确方法的例子。

myCompletionHandler 到 .animate 完成处理程序?

3 回复 | 直到 7 年前

1

8

Dávid Pásztor 7 年前

如果您想将自己的闭包作为输入参数传递给 UIView.animate ,您需要匹配闭包的类型,因此 myCompletionHandler ((Bool) -> ())? ,就像 completion .

func hide(animated: Bool, myCompletionHandler: ((Bool) -> ())?) {
    if animated {
        transform = CGAffineTransform(scaleX: 0.7, y: 0.7)

        UIView.animate(withDuration: 0.3, delay: 0, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.5, options: [], animations: {
            self.alpha = 0
            self.transform = CGAffineTransform.identity
        }, completion: myCompletionHandler) // I want to run 'myCompletionHandler' in this completion handler
    }
}

你可以这样称呼它:

hudView.hide(animated: true, myCompletionHandler: { success in
    //animation is complete
})

2

0

Damien 7 年前

func hide(animated: Bool, myCompletionHandler: () -> Void) {
    if animated {
        transform = CGAffineTransform(scaleX: 0.7, y: 0.7)

        UIView.animate(withDuration: 0.3, delay: 0, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.5, options: [], animations: {
            self.alpha = 0
            self.transform = CGAffineTransform.identity
        }, completion: { (success) in
            myCompletionHandler()
        })
    }
}

3

0

Arpit Jain Vivek Sharma 7 年前

You can create your function as,

func hide(_ animated:Bool, completionBlock:((Bool) -> Void)?){

}

And you can call it as,

self.hide(true) { (success) in
   // callback here     
}