kotlin 覆盖属性

方法重载 (Method Overriding)

• Method overriding allows derived class has the same function name and signature as the base class

  方法重写允许派生类具有与基类相同的函数名称和签名

• By method overriding we can provide different implementation into the derived class of base class methods.

  通过方法重写，我们可以为基类方法的派生类提供不同的实现。

• By default method is final in Kotlin class, to make them overridable declare the method with 'open'

  默认情况下，方法在Kotlin类中是final，要使其可重写，请使用“ open”声明该方法

• The open modifier does not affect when added on members of a final class (i.e.. a class with no open modifier).

  当将open修饰符添加到最终类的成员(即没有open修饰符的类)的成员上时，则不受影响。

• Marked function with 'override' into derived class while overriding the base class method.

  在覆盖基类方法的同时，将具有“覆盖”功能的标记为派生类。

• Use 'super' to call the base class implementation of the method from child class

  使用“ super”从子类中调用方法的基类实现

Kotlin中的方法重写程序 (Program for method overriding in Kotlin)

package com.includehelp//Declare Base class, //marked with 'open' to make inheritableopen class Person{    //marked function with 'open' to make    //overridable    open fun printMessage(){        println("Message for Person")    }}//Derived class extends Person classclass Child: Person() {    //Override base class methods    override fun printMessage(){        println("Message for Child")    }}//marked derived class with 'open' //to make further inheritable by its //child classopen class Boy : Person(){        //A member marked override is itself open,         //i.e. it may be overridden in subclasses.        //If you want to prohibit re-overriding, use final        final override fun printMessage(){            println("Message for Boys")        }}//Derived classclass Hero : Boy() {    //Declare member function    fun printData(){        //calling , Boy Class Implementation         //of printMessage() function        super.printMessage()        println("Hello Hero")    }}fun main(args:Array
    
     ){    //Create Person class Instance and Called Methods,     //it will invoke Base class version of  methods    Person().printMessage()    //Create class Instance and Called Methods,    //it will invoke Child class version of  methods    Child().printMessage()    //Create class Instance and Called Methods    Hero().printData()}
    

Output:

输出：

Message for PersonMessage for ChildMessage for BoysHello Hero

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kotlin 覆盖属性