kotlin 抽象类_Kotlin程序| 抽象类的例子

傷城~ 2023-03-05 12:43 15阅读 0赞

kotlin 抽象类

## 抽象类 **(**Abstract Class**)** ##

*  Use the abstract keyword to mark the class as an **abstract class**.
    
    使用abstract关键字将类标记为**抽象类** 。
 *  An **abstract class** can't be Instantiated.but they can be subclassed.
    
    **抽象类**不能被实例化，但是可以被子类化。
 *  An **abstract class** is by default inheritable not need to mark with 'open'.
    
    默认情况下， **抽象类**是可继承的，不需要标记为“ open”。
 *  Abstract members( (properties and function ) is by default 'open'
    
    抽象成员((属性和函数)默认情况下为“打开”
 *  Members (properties and function ) of an abstract class can be abstract or non-abstract, to mark them abstract explicitly use abstract keyword
    
    抽象类的成员(属性和函数)可以是抽象的，也可以是非抽象的，使用abstract关键字将它们明确标记为抽象
 *  An abstract member does not have an implementation in its class.
    
    抽象成员的类中没有实现。
 *  If any members of the class is abstract then the class must be declared as abstract class.
    
    如果该类的任何成员是抽象类，则必须将该类声明为抽象类。

## Kotlin中的抽象类程序 **(**Program for abstract class in Kotlin**)** ##

package com.includehelp
    
    //Declare abstract class
    abstract class PaintSheet {
        //abstract property without value
        abstract var value:Int
    
        //Init Block of Base Class
        init {
            println("Init Block, Base Class")
        }
    
        //marked function with 'open' to make overridable
        open fun paint(){
            println("Paint Method , Base Class Implementation")
        }
    
        //final method, so cant be override in subclass
        fun sketch(){
            println("Sketch Method , From Base Class!")
        }
    
        //Abstract method, without implementation
        abstract fun draw()
    }
    
    //declare sub class extendign super class
    class Painting : PaintSheet() {
    
        //override abstract property in subclass
        override var value=10
    
        //Init Block , Sub class
        init {
            println("Init Block, Child Class")
    
            //Call Super class implementation of Paint method
            super.paint()
        }
    
        //implement base class abstract method
        override fun draw(){
            println("draw Method , override in Child Class")
        }
    
        //Override method, provide different implementation
        override fun paint(){
            println("Paint Method , Child Class Implementation")
        }
    
        //Declare Method to print Property value
        fun printValue(){
            println("Value : $value")
        }
    }
    
    //Main Function, Entry Point of Program
    fun main(args:Array<String>){
        //create instance of Painting class (Child class)
        val paint = Painting()
    
        //call draw method
        paint.draw()
    
        //call paint method
        paint.paint()
    
        //call sketch method
        paint.sketch()
    
        //Call printValue method
        paint.printValue()
    }

**Output:**

**输出：**

Init Block, Base Class
    Init Block, Child Class
    Paint Method , Base Class Implementation
    draw Method , override in Child Class
    Paint Method , Child Class Implementation
    Sketch Method , From Base Class!
    Value : 10

> 翻译自: [https://www.includehelp.com/kotlin/example-of-abstract-class.aspx][https_www.includehelp.com_kotlin_example-of-abstract-class.aspx]

kotlin 抽象类

[https_www.includehelp.com_kotlin_example-of-abstract-class.aspx]: https://www.includehelp.com/kotlin/example-of-abstract-class.aspx