同一类Kotlin中的@Provides和@Binds方法

问题描述

在匕首2.11之后，我们可以使用@Binds批注并在这种情况下将模块标记为抽象，这比具体方法更有效.

After dagger 2.11 we can use a @Binds annotation and mark our Module as abstract in this case which is more efficient than a concrete.

如果我的模块同时具有@Provides和@Binds方法，则我有两个选择:

If my Module has both @Provides and @Binds methods, I have two options :

1. 最简单的方法是将@Provides实例方法标记为静态.

1. Simplest would be to mark your @Provides instance methods as static.

如果有必要将其保留为实例方法，则可以将您的模块一分为二并提取所有@Binds方法进入一个抽象模块.

If it is necessary to keep them as instance methods, then you cansplit your module into two and extract out all the @Binds methodsinto an abstract Module.

第二个选项在Java和Kotlin中运行良好，但是第一个选项在Java中运行良好，但是我不知道如何在Kotlin中实现相同的功能.如果我将@Provides方法移至Companion对象，则会抛出Error:(30, 1) error: @Provides methods can only be present within a @Module or @ProducerModule.如何在Kotlin中做到这一点.

The second option works fine in Java and Kotlin but the first option works fine in Java but I don't know how to implement the same in Kotlin. If I move @Provides method to Companion object it throw Error:(30, 1) error: @Provides methods can only be present within a @Module or @ProducerModule.How can do this in Kotlin.

第二个选项:(正在运行)

ApplicationModule.kt

ApplicationModule.kt

@Module(includes = [ApplicationModule.Declarations::class])
abstract class ApplicationModule {
    @Module
    internal interface Declarations {
        @Binds
        fun bindContext(application: Application): Context
    }

    @Provides
    @Singleton
    fun provideMvpStarterService(): MvpStarterService {
        return MvpStarterServiceFactory.makeStarterService()
    }
}

第一个选项 :(不起作用)

ApplicationModule.kt

ApplicationModule.kt

@Module
abstract class ApplicationModule {
    //expose Application as an injectable context
    @Binds
    internal abstract fun bindContext(application: Application): Context

    companion object {
        @JvmStatic
        @Provides
        @Singleton
        fun provideMvpStarterService(): MvpStarterService {
            return MvpStarterServiceFactory.makeStarterService()
        }
    }
}

生成的第一个选项的Java文件:

Generated Java file for first option:

@kotlin.Metadata(mv = {1, 1, 9}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u001a\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0002\b\u0002\n\u0002\u0018\u0002\n\u0000\n\u0002\u0018\u0002\n\u0002\b\u0003\b\'\u0018\u0000 \b2\u00020\u0001:\u0001\bB\u0005\u00a2\u0006\u0002\u0010\u0002J\u0015\u0010\u0003\u001a\u00020\u00042\u0006\u0010\u0005\u001a\u00020\u0006H!\u00a2\u0006\u0002\b\u0007\u00a8\u0006\t"}, d2 = {"Lio/mywebsie/di/ApplicationModule;", "", "()V", "bindContext", "Landroid/content/Context;", "application", "Landroid/app/Application;", "bindContext$app_debug", "Companion", "app_debug"})
@dagger.Module()
public abstract class ApplicationModule {
    public static final io.mywebsie.di.ApplicationModule.Companion Companion = null;

    @org.jetbrains.annotations.NotNull()
    @dagger.Binds()
    public abstract android.content.Context bindContext$app_debug(@org.jetbrains.annotations.NotNull()
    android.app.Application application);

    public ApplicationModule() {
        super();
    }

    @org.jetbrains.annotations.NotNull()
    @javax.inject.Singleton()
    @dagger.Provides()
    public static final io.mywebsie.data.remote.MvpStarterService provideMvpStarterService() {
        return null;
    }

    @kotlin.Metadata(mv = {1, 1, 9}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0002\b\u0002\n\u0002\u0018\u0002\n\u0000\b\u0086\u0003\u0018\u00002\u00020\u0001B\u0007\b\u0002\u00a2\u0006\u0002\u0010\u0002J\b\u0010\u0003\u001a\u00020\u0004H\u0007\u00a8\u0006\u0005"}, d2 = {"Lio/mywebsie/di/ApplicationModule$Companion;", "", "()V", "provideMvpStarterService", "Lio/mywebsie/data/remote/MvpStarterService;", "app_debug"})
    public static final class Companion {

        @org.jetbrains.annotations.NotNull()
        @javax.inject.Singleton()
        @dagger.Provides()
        public final io.mywebsie.data.remote.MvpStarterService provideMvpStarterService() {
            return null;
        }

        private Companion() {
            super();
        }
    }
}

更新:

感谢您在评论中提供的 @David Medenjak 链接可以通过两种方式来实现第一种选择.

Thanks to @David Medenjak the link you provided in comment made everything clear I came across two ways to achieve the first option.

更新的代码:

第一个选项:(正在工作)

ApplicationModule.kt

ApplicationModule.kt

@Module(includes = [ApplicationModule.AModule::class])
abstract class ApplicationModule {

    @Binds
    abstract fun bindContext(application: Application): Context

    @Module
    object AModule {
        @JvmStatic
        @Provides
        @Singleton
        fun provideMvpStarterService(): MvpStarterService {
            return MvpStarterServiceFactory.makeStarterService()
        }
    }
}

或

@Module
abstract class ApplicationModule {
    @Binds
    abstract fun bindContext(application: Application): Context

    @Module
    companion object {
        @Provides
        @Singleton
        fun provideMvpStarterService(): MvpStarterService {
            return MvpStarterServiceFactory.makeStarterService()
        }
    }
}

两种方法都很好，但是由于某种原因，第一种选择对我来说似乎并不吸引人，所以我更喜欢第二种选择.

Both works just fine but for some reason the first option does not look appealing to me so I prefer the second option.

推荐答案

下面是一个示例代码，用于演示如何在单个Kotlin class中使用Binds和Provides批注的方法:

Here's an example code to demonstrate how to use Binds and Provides annotated methods in a single Kotlin class:

@Module
abstract class MessagesPresentationModule {

    @Module
    companion object {
        const val MESSAGES = 0x00

        @JvmStatic
        @Provides
        fun provideRecyclerAdapter(
            itemComparator: DisplayItemComperator,
            factoryMap: Map<Int, ViewHolderFactory>,
            binderMap: Map<Int, ViewHolderBinder>,
            androidPreconditions: AndroidPreconditions
        ): RecyclerViewAdapter {
            return RecyclerViewAdapter(
                itemComperator = itemComparator,
                viewHolderFactoryMap = factoryMap,
                viewBinderFactoryMap = binderMap,
                androidPreconditions = androidPreconditions
            )
        }
    }

    @Binds
    @IntoMap
    @IntKey(MESSAGES)
    internal abstract fun provideMessagesViewModelFactory(factory: MessagesViewHolder.MessageViewHolderFactory): ViewHolderFactory

    @Binds
    @IntoMap
    @IntKey(MESSAGES)
    internal abstract fun provideMessagesViewHolderBinder(binder: MessagesViewHolder.MessagesViewHolderBinder): ViewHolderBinder
}

这篇关于同一类Kotlin中的@Provides和@Binds方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！