Swift语言中用了willSet和didSet
发布时间：2020-12-14 07:09:27 所属栏目：百科 来源：网络整理
导读：在Swift语言中用了willSet和didSet这两个特性来监视属性的除初始化之外的属性值变化 import Foundation class People : NSObject { //普通属性 var name1:String = "" var lastName:String = "" var nickName:String = "" //计算属性 var fullName:String { g
|
在Swift语言中用了willSet和didSet这两个特性来监视属性的除初始化之外的属性值变化 import Foundation class People : NSObject { //普通属性 var name1:String = "" var lastName:String = "" var nickName:String = "" //计算属性 var fullName:String { get { return nickName + " " + name1 + " " + lastName } } //带属性监视器的普通属性 var age:Int = 0 { //我们需要在age属性变化前做点什么 willSet { println("Will set an new value (newValue) to age") } //我们需要在age属性发生变化后，更新一下nickName这个属性 didSet { println("age filed changed form (oldValue) to (age)") if age<10 { nickName = "Little" }else { nickName = "Big" } } } func toString() -> String { return "Full Name: (fullName) " + ",Age: (age) " } } var me = People() me.firstName = "Zhang" me.lastName = "San" me.age = 20 println(me.toString()) /*程序输出 Will set an new value 20 to age age filed changed form 0 to 20 Full Name: Big Zhang San,Age: 20 */ （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |