匕首模块类的提供程序功能的注释 [英] The annotation for provider function of dagger module class

问题描述

我正在用Kotlin和Dagger 2开发一个Android项目.我有一个NetworkModule，其中定义了一些提供程序功能.

I am developing an Android project with Kotlin and Dagger 2. I have a NetworkModule in which I define some provider functions.

@Module
object NetworkModule {
   @Provides
   @JvmStatic  // Here uses @JvmStatic
   internal fun provideSomething(): Something {
      ...
   }
}

我看到有人使用Kotlin @JvmStatic，而有人使用dagger的@Reusable来注释提供程序功能:

I see some people use kotlin @JvmStatic and some use dagger's @Reusable to annotate the provider function:

@Module
object NetworkModule {
   @Provides
   @Reusable  // Here uses @Reusable
   internal fun provideSomething(): Something {
      ...
   }
}

和..某些人同时使用:

And..some people use both:

@Module
object NetworkModule {
   @Provides
   @JvmStatic // Here use both @JvmStatic
   @Reusable  // and uses @Reusable
   internal fun provideSomething(): Something {
      ...
   }
}

我很困惑.我的两个问题是:

I get confused. My two questions are:

1. 注释@JvmStatic和/或@Reusable的动机是什么?这样做的原因是什么?这样做的好处是什么?

1. What is the motivation to annotate either @JvmStatic and/or @Reusable ? What's the reason behind or what is the benefit doing so?

使用@JvmStatic或@Reusable哪个更好?还是一个很好?还是应该同时使用两者?如果是，那么同时使用两者的原因是什么?

Which one is better to use @JvmStatic or @Reusable ? Or either one is fine? Or should I use both, if so what is the reason to use both then?

推荐答案

如果您将模块声明为Kotlin对象，则需要@JvmStatic.该限制已通过 dagger 2.25 删除.您也可以选中此问题以获取更多信息.

If you declare your module as a Kotlin object, @JvmStatic was required. That limitation was removed with dagger 2.25 You can also check this issue for more info.

如果您使用Dagger 2.25或更高版本，则不再需要使用@JvmStatic.

If you use Dagger 2.25 or newer there is no reason to use @JvmStatic anymore.

来自@Reusable文档:

一个范围，该范围指示绑定返回的对象可以(但可能不会)被重用.

A scope that indicates that the object returned by a binding may be (but might not be) reused.

{@ code @Reusable}在您希望限制一种类型的配置数量时有用，但是没有特定的生存期，在该生存期中只能有一个实例.

{@code @Reusable} is useful when you want to limit the number of provisions of a type, but there is no specific lifetime over which there must be only one instance.

如果您在多个位置注入相同的对象，并且具有相同的实例不是问题，那么这可以帮助您不必为每种用法创建一个新对象.

If you inject the same thing in multiple places, and having the same instance is not a problem, this can help not to create a new object for each usage.

@JvmStatic和@Reusable彼此不相关，根据您的需要，您可以使用一个，另一个或两者.

@JvmStatic and @Reusable are not related to each other, depending on your need you can use one, the other or both of them.

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