August 2020
Intermediate to advanced
483 pages
11h 24m
Chinese
Content preview from Head First Kotlin程序设计
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122 第
5
章
understanding inheritance
继承帮助你避免代码重复
当你开发一个拥有多个类的大型应用程序，你需要开始考虑使用继
承。当你设计继承关系时，你会把公共的代码放到一个类中，然后
让其他更加特殊的类继承这些代码。当你需要修改这些代码的时候，
你只需要更新一个地方，修改就会反映到继承了该行为的所有类中。
包含这些公共代码的类叫作父类，继承父类的类叫作子类。
一个父类包含由
一个或多个子类
继承的公共属性
和方法。
一个子类包含额
外的属性和方法，
并可以覆盖从父
类继承的信息。
一个继承的例子
假设你有名为Car和ConvertibleCar的类。
Car类包含了生成一个通用汽车的属性和方法，如make和model属
性，以及accelerate、applyBrake和changeTemperature方法。
ConvertibleCar类是Car类的子类，因此它继承Car类的所有属性
和方法。但是ConvertibleCar类可以增加它自己特有的方法和属
性，也可以覆盖从Car类继承的信息。
Car
make
model
accelerate()
applyBrake()
changeTemperature()
ConvertibleCar
changeTemperature()
openTop()
closeTop()
ConvertibleCar类新增了名为openTop和closeTop的方法。同时
覆盖了changeTemperature方法，因此如果车顶打开时车子太冷，
它会关闭车顶。
有时将父类称为基类 ...
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