前言:

   今天来看 类别 / 初始化 / 继承

大纲:

class 结构

宣告　名称　　主要建构式　　　传入参数　
class ironman constructor(titleName: String, playerName: String){…｝

主要建构式 constructor 可省略
 class ironman(titleName: String, playerName: String){…｝

无定义建构式参数的类别 / 初始化

var mNotParameter = ironmanNotParameter()
mNotParameter.printPlayerInfo()

class ironmanNotParameter constructor(){
    //主要建构式  constructor()
    //第二建构式
    constructor(titleName: String):this()

    //初始化
    init{ println("Ithome 铁人赛 2021")}
    fun printPlayerInfo(){
        println("Title: Kotlin Android 30天，从 0 到 ML , Player: Kevin ")
    }
}

定义建构式参数的类别

var mPlayer = ironmanDefine()
mPlayer.mTitleName = "Kotlin Android 30天，从 0 到 ML"
mPlayer.mPlayerName = "Kevin"
mPlayer.printPlayerInfo()

class ironmanDefine {
    var mTitleName:String = ""
    var mPlayerName:String = ""

    fun printPlayerInfo(){
        println("Title: $mTitleName , Player: $mPlayerName ")
    }
}

继承类别

var mIronmanTitle = ironman("Kotlin Android 30天，从 0 到 ML", "Kevin")
mIronmanTitle.printPlayerInfo()

//继承父类别要加 open
open class ironman constructor(titleName: String, playerName: String){

    var mTitle = titleName
    var mPlayer = playerName
    open fun printPlayerInfo(){
        println("Title: $mTitle , Player: $mPlayer ")
    }
}

//多加一个开赛参数
var mIronPlayer = ironPlayer("Kotlin Android 30天，从 0 到 ML", "Kevin","9/6")
//覆写父类别方法
mIronPlayer.printPlayerInfo()
//子类别方法
mIronPlayer.printironPlayerInfo()


//子类别继承父类别，父类别前面要加 open
//子类别继承父类别，子类别建构式多加参数
//子类别继承父类别，子类别覆写父类别方法
class ironPlayer constructor(titleName: String, 
                             playerName: String,
                             var startDay:String
                             ): ironman(titleName, playerName){

    var mTitleName = super.mTitle
    var mPlayerName = super.mPlayer
    var mStartDay :String = startDay

    override fun printPlayerInfo(){
        println("override Title: $mTitleName , Player: $mPlayerName ")
    }

    fun printironPlayerInfo(){
        println("Title: $mTitleName , 
                Player: $mPlayerName , mStartDay = $mStartDay")
    }
}

执行结果:

参考:

https://kotlinlang.org/docs/classes.html
https://kotlinlang.org/docs/inheritance.html