将参数传递给Swift中由NSTimer调用的方法 [英] Passing parameters to a method called by NSTimer in Swift

问题描述

我正在尝试将参数传递给我的代码中由NSTimer调用的方法。这是一个例外。这就是我的做法。 Circle是我的自定义类。

I'm trying to pass an argument to a method that is called by NSTimer in my code. It is throwing an exception. This is how I'm doing it. Circle is my custom class.

    var circle = Circle()
    var timer = NSTimer.scheduledTimerWithInterval(1.0, target: self, selector: animate, userInfo: circle, repeats: true)

以下是方法被称为

    func animate(circle: Circle) -> Void{
      //do stuff with circle
    }

注意：方法与被调用的类相同。所以我相信我已经正确设置了目标。

Note: The method is in the same class that it is being called. So I believe i've set the target correctly.

推荐答案

与 NSTimer一起使用的选择器传递 NSTimer 对象，因为它是唯一的参数。将圆形对象放在 userInfo 中，然后在计时器触发时将其解压缩。

The selector you use with NSTimer is passed the NSTimer object as it's one and only parameter. Put the circle object in it as userInfo and you can extract it when the timer fires.

var circle = Circle()
var timer = NSTimer.scheduledTimerWithInterval(1.0, target: self, selector: "animate:", userInfo: circle, repeats: true)

func animate(timer:NSTimer){
  var circle = timer.userInfo as Circle
  //do stuff with circle
}

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