在Swift中使用闭包来实现两个界面的传值
例如:有A类和B类.
B类
//声明闭包
typealias valueBlock = (Float)->()
var returnPrice: valueBlock?
//调用该闭包
self.returnPrice?(price)
A类
let sb = UIStoryboard(name:"Main", bundle: nil)
let vc = sb.instantiateViewControllerWithIdentifier("keypadViewVC") as! keypadViewVC
//B类的回调
vc.returnPrice = {price in self.gratuityBtn.setTitle(String(format: "%.2f", price), forState:UIControlState.Normal)}
self.presentViewController(vc, animated: true, completion: nil)
