1.protocol中的方法参数不能有默认值
protocol Eatable {
//func eat(foodName:String = "大米") //报错
func eat(foodName:String) //正确
}
2.遵从protocol的class 或者 struct需要实现其中的方法,否则会报错
class Person:Eatable{
func eat(foodName: String) {
}
}
struct Pig:Eatable{
func eat(foodName: String) {
}
}
3.protocol中还可以声明变量，遵从的class必须有这样的变量或者getter setter方法
protocol Eatable{
var foodName : String {get set}
var eatMethod : String { get }
func eat()
}
class Person : Eatable{
var foodName: String = "大米"
var eatMethod: String = "用嘴吃"
func eat() {
}
}
eatMethod 还可以这样实现
class Person : Eatable{
private var innerEatMethod = "用嘴吃"
var eatMethod: String {
get {
return innerEatMethod
}
}
var foodName: String = "大米"
func eat() {
}
}
4.一个protocol可以继承另外一个protocol
protocol EatDrinkable : Eatable {
var drinkMethod : String {get set}
func drink()
}
class Person : EatDrinkable{
var foodName: String = "上海记忆酸奶"
var eatMethod: String = "用嘴吃"
var drinkMethod: String = "用嘴喝"
func eat() {
}
func drink() {
}
}
5.一个类可以遵从多个协议
protocol Runable {
func run ()
}
protocol Jumpable {
func jump()
}
class Person : Runable,Jumpable{
func jump() {
}
func run() {
}
}
