前言:

   今天來看 類別 / 初始化 / 繼承

大綱:

class 結構

宣告　名稱　　主要建構式　　　傳入參數　
class ironman constructor(titleName: String, playerName: String){…｝

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

無定義建構式參數的類別 / 初始化

var mNotParameter = ironmanNotParameter()
mNotParameter.printPlayerInfo()

class ironmanNotParameter constructor(){
    //主要建構式  constructor()
    //第二建構式
    constructor(titleName: String):this()

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

定義建構式參數的類別

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

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

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

繼承類別

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

//繼承父類別要加 open
open class ironman constructor(titleName: String, playerName: String){

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

//多加一個開賽參數
var mIronPlayer = ironPlayer("Kotlin Android 30天，從 0 到 ML", "Kevin","9/6")
//覆寫父類別方法
mIronPlayer.printPlayerInfo()
//子類別方法
mIronPlayer.printironPlayerInfo()


//子類別繼承父類別，父類別前面要加 open
//子類別繼承父類別，子類別建構式多加參數
//子類別繼承父類別，子類別覆寫父類別方法
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")
    }
}

執行結果:

參考:

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