kotlin實現繼承

遺產 (Inheritance)

• Inheritance is a mechanism wherein a new class is derived from an existing class.

  繼承是一種機制，其中新類是從現有類派生的。

• All Kotlin Classes have a common Superclass 'Any', it is the Default Superclass with no Super Type declared.

  所有Kotlin類都有一個通用的超類“ Any”，它是沒有聲明任何超類型的默認超類。

  class Student  // implicitly inherits from Any
  
  

• 'Any' Class has three methods

  “任何”課程有三種方法

  1. equals()
  2. hashCode()
  3. toString()

• By Default All class is Final in Kotlin, They can't be inherited.

  默認情況下，所有類在Kotlin中都是Final，不能繼承。

• Use 'open' keyword, to make class inheritable,

  使用“ open”關鍵字，使類可繼承，

  open class <class name>  // make class inheritable
  
  

• To declare explicit supertype, placer base class name after colon into the class header.

  要聲明顯式超類，在冒號之后將放置器基類名稱放入類標題中。

  open class Base{}
  class Derived : Base{}
  
  

Kotlin繼承計劃 (Program for Inheritance in Kotlin)

package com.includehelp
//Declare class, use 'open' keyword 
//to make class inheritable
//Class without declare primary constructor
open class Company{
//member function
fun getCompany(){
println("Base Methods : Company Info")
}
}
//Declare class using inheritance
class Department : Company() {
//member function
fun getDept(){
println("Derived Method :  Dept Info")
}
}
//Declare class, use 'open' keyword 
//to make class inheritable
open class Shape(val a:Int){
fun getBaseValue(){
println("Base value : $a")
}
}
//if derived class has primary constructor 
//then base class can initialized there
//using primary constructor parameters
class Circle(val b:Int): Shape(b) {
fun getChildValue(){
println("Child value : $b")
}
}
//Main Function, Entry point of program
fun main(args:Array<String>){
//create derived class object
val company = Department()
//access base class function
company.getCompany()
//access derived class function
company.getDept()
//create derived class object and passed parameter
val shape = Circle(20)
//access base class function
shape.getBaseValue()
//access derived class function
shape.getChildValue()
}

Output:

輸出：

Base Methods : Company Info
Derived Method :  Dept Info
Base value : 20
Child value : 20

翻譯自: https://www.includehelp.com/kotlin/example-of-inheritance.aspx

kotlin實現繼承