1.协议和方法前使用@objc关键字
2.扩展extension
protocol SomeProtocol {
func requiredFunc()
func optionalFunc()
}
extension SomeProtocol {
func optionalFunc() {
print("optional func")
}
}
使用
extension ViewController : SomeProtocol {
func requiredFunc() {
print("required func")
}
}
