error: @Component.Builder is missing setters for required modules or components in Dagger 2 instead of having setter method

Question

我是 dagger 2 的新手。我在 kotlin 上制作了一个 CarComponent，我试图在不调用 petroleEngineModule 的情况下用 horsePower 值调用我的 DaggerCarComponent。以下是我的代码：

import dagger.BindsInstance
import dagger.Component
import javax.inject.Singleton

@Component (
    modules = [WheelModule::class, PetrolEngineModule::class]
)
interface CarComponent {

    fun getCar(): Car

    fun inject(mainActivity: MainActivity)

    @Component.Builder
    interface Builder {

        @BindsInstance
        fun horsePower(horsePower : Int) : Builder

        fun build(): CarComponent
    }
}

这是PetrolEngine.kt:

package com.example.daggerapp

import android.util.Log
import javax.inject.Inject

class PetrolEngine : Engine {

    private var horsePower : Int

    @Inject constructor(horsePower: Int){
        this.horsePower = horsePower
    }

    override fun start() {
        Log.d("Engine", "Broom..., horsePower: ${this.horsePower}")
    }
}

这是PetrolEngineModule.kt:

package com.example.daggerapp

import dagger.Module
import dagger.Provides
import javax.inject.Inject

@Module
class PetrolEngineModule {

    private var horsePower: Int

    @Inject constructor(horsePower: Int) {
        this.horsePower = horsePower
    }

    @Provides
    fun provideHorsePower(): Int {
        return horsePower
    }

    @Provides
    fun provideEngine(engine: PetrolEngine): Engine
    {
        return engine
    }
}

我在此处将 DaggerComponent 添加为 DaggerCarComponent：

package com.example.daggerapp

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import javax.inject.Inject

class MainActivity : AppCompatActivity() {
    @Inject
    lateinit var car:Car

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val daggerCar: CarComponent = DaggerCarComponent.builder().petrolEngineModule(PetrolEngineModule(140)).build()
        daggerCar.inject(this)

        Log.d("Car instance", "$car")
        car.drive()
    }
}

我正在学习这个教程：https://www.youtube.com/watch?v=3tIvekCTSJg&list=PLrnPJCHvNZuA2ioi4soDZKz8euUQnJW65&index=8

Answer 1

在您的生成器中：

@BindsInstance
    Builder horsePower(@Named("horse_power") int horsePower);

在此之后，您将能够从 MainActivity 传递 horsePower，而无需在您的 PetrolEngine 构造函数中以相同的方式传递 PetrolEngineModule.And 的实例：

@Inject
public PetrolEngine(@Named("horse_power") int horsePower) {
    this.horsePower = horsePower;
}

并且在您的 PetrolEngineModule 中，您可以删除所有内容，只为 PetrolEngine 保留 @Provides。

Answer 2

删除模块 class 中的 @Inject，因为在 @Component.Builder

中传递 horsePower 时 @BindsInstance 在做什么

Answer 3

只是针对未来观众的优化。只需用它替换现有代码即可。现在 Dagger 不会创建 --Provide-- class 来提供 PetrolEngine 的实例。

如有错误请改进代码


    @Module
    abstract class PetrolEngineModule {

        @Binds
        abstract fun bindEngine(engine: PetrolEngine): Engine
    }

error: @Component.Builder is missing setters for required modules or components in Dagger 2 instead of having setter method

error: @Component.Builder is missing setters for required modules or components in Dagger 2 instead of having setter method

android

kotlin

dagger

android-studio

dagger-2