【Kotlin】Kotlin笔记4-面向对象编程2(接口,函数的可见性修饰符)

冷不防 2022-11-16 04:53 214阅读 0赞

### Kotlin笔记4-面向对象编程2-接口,数据类与单例类 ###

**3.2 面向对象编程2**

*  **接口**

> **interface**

`Example:`

interface Study {
        fun readBooks()
        fun doHomework(){
            println("do homework default implementation.")
        }
    }

`继承父类与实现接口`

class Student5(name: String, age: Int) : Person2(name, age), Study {
        override fun readBooks() {
            println("$name is reading.")
        }
    
        override fun doHomework() {
            println("$name is doing homework.")
        }
    }

`面向接口编程: 多态`

fun main() {
        val student = Student5("Jack", 19)
        doStudy(student)
    }
    
    fun doStudy(study: Study) {
        study.readBooks()
        study.doHomework()
    }

`接口默认实现`

interface Study {
    	fun readBooks()
    	fun doHomework() {
    		println("do homework default implementation."
    	}
    }

--------------------

*  **函数的可见性修饰符**

<table> 
 <thead> 
  <tr> 
   <th>Java</th> 
   <th>public</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>public</td> 
   <td>public</td> 
  </tr> 
  <tr> 
   <td>private</td> 
   <td>private</td> 
  </tr> 
  <tr> 
   <td>protected</td> 
   <td>protected</td> 
  </tr> 
  <tr> 
   <td>default</td> 
   <td>internal</td> 
  </tr> 
 </tbody> 
</table>

*Kotlin,Java修饰符对照*

<table> 
 <thead> 
  <tr> 
   <th>修饰符</th> 
   <th>Kotlin</th> 
   <th>Java</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>private</td> 
   <td>对当前类内部可见</td> 
   <td>当前类可见</td> 
  </tr> 
  <tr> 
   <td>public</td> 
   <td>默认</td> 
   <td>当前类可见</td> 
  </tr> 
  <tr> 
   <td>portected</td> 
   <td>对当前类和子类可见</td> 
   <td>…同一包路径下的类可见</td> 
  </tr> 
  <tr> 
   <td>internal</td> 
   <td>对同一模块的类可见</td> 
   <td>无</td> 
  </tr> 
  <tr> 
   <td>default</td> 
   <td>无</td> 
   <td>默认,同一包路径下的类可见</td> 
  </tr> 
 </tbody> 
</table>