Kotlin中的“公开"和“公开"有什么区别? [英] What is the difference between 'open' and 'public' in Kotlin?

问题描述

我是Kotlin的新手，在open和public关键字之间感到困惑.谁能告诉我这些关键字之间的区别吗?

I am new to Kotlin and I am confused between open and public keywords. Could anyone please tell me the difference between those keywords?

推荐答案

open关键字的意思是开放扩展":

The open keyword means "open for extension":

类上的open注释与Java的final相反:它允许其他人从此类继承.默认情况下，Kotlin中的所有类都是final，与有效的Java，第17项:设计和继承文档或禁止继承相对应.

The open annotation on a class is the opposite of Java's final: it allows others to inherit from this class. By default, all classes in Kotlin are final, which corresponds to Effective Java, Item 17: Design and document for inheritance or else prohibit it.

您还需要明确说明要使其可覆盖的方法，并用open标记:

You also need to be explicit about methods you want to make overridable, also marked with open:

open class Base {
    open fun v() {}
    fun nv() {}
}

public关键字用作可见性修饰符，可以应用于类，函数等. 请注意，如果未明确指定其他任何内容，则public是默认设置:

The public keyword acts as a visibility modifier that can be applied on classes, functions etc. Note that public is the default if nothing else is specified explicitly:

如果您未指定任何可见性修饰符，则默认使用public，这意味着您的声明将在任何地方都可见

If you do not specify any visibility modifier, public is used by default, which means that your declarations will be visible everywhere

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