class ClassViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
// 1.子类对象转化为父类对象
let food_Apple: Food = Apple(footName: "Apple")
food_Apple.Nickname()
let food_Coke: Food = Coke(footName: "Coca-Cola")
food_Coke.Nickname()
// 2，父类对象转为子类对象 as! as?
// 父类对象转化为子类对象，父类转化为子类需要使用 as! 如果当前对象是父类对象，但是他如果是子类对象转化过来的，那么可以转化回去
let apple = food_Apple as! Apple
apple.footType = "Green foot"
apple.Nickname()
let coke = food_Coke as! Coke
coke.footType = "Junk food"
coke.Nickname()
// 如果当前转化的子类的对象的父类，并不是有改子类转化成的父类，则会报错
// 如果我们需要将当前父类对象转为子类对象但是并不确定 当前对象是否为子类对象转化过来的，该如何处理？ Swift为我们提供一个方法 as?
if let a = food_Apple as? Apple {
a.footType = "Green foot"
a.Nickname()
print("子类对象")
} else {
print("非子类对象")
}
if let a1 = food_Coke as? Coke {
a1.footType = "Junk food"
a1.Nickname()
print("子类对象")
} else {
print("非子类对象")
}
// 3 如何判断某一个对象是不是这个类的对象 可以 使用 对象 is 类 来判断
// 我们会发现判断子类对象是不是父类对象返回也是true
print(food_Apple is Apple)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
class Food {
var name = ""
init(footName: String) {
name = footName
}
func Nickname() {
print("I am an \(name)")
}
}
class Apple: Food {
var footType = ""
override func Nickname() {
print("I am an \(name),I tried \(footType) ")
}
}
class Coke: Food {
var footType = ""
override func Nickname() {
print("I am an \(name),I tried \(footType) ")
}
}
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