9、探索Swift开发：从安全委托到macOS笔记应用搭建

探索Swift开发：从安全委托到macOS笔记应用搭建

1. Swift中的安全委托机制

在Swift编程里，委托模式是一种强大的工具，它能够让一个对象将特定任务委托给另一个对象。下面是一个展示安全委托机制的代码示例：

class House {
    // The delegate can be any object that conforms
    // to the HouseSecurityDelegate protocol
    var delegate : HouseSecurityDelegate?
    func burglarDetected() {
        // Check to see if the delegate is there, then call it
        delegate?.handleIntruder()
    }
}
class GuardDog : HouseSecurityDelegate {
    func handleIntruder() {
        print("Releasing the hounds!")
    }
}
let myHouse = House()
myHouse.burglarDetected() // does nothing
let theHounds = GuardDog()
myHouse.delegate = theHounds
myHouse.burglarDetected() // prints "Releasing the hounds!"

在这个示例中， Hous