dagger2使用

2.依赖

apply plugin: 'kotlin-kapt'
-----------------------------------------------------------------------------
   compileOptions {
        sourceCompatibility = 1.8
        targetCompatibility = 1.8
    }
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_1_8.toString()
    }
-----------------------------------------------------------------------------
    api 'com.google.dagger:dagger:2.27'
    kapt 'com.google.dagger:dagger-compiler:2.27'
    api 'com.google.dagger:dagger-android:2.27'
    kapt 'com.google.dagger:dagger-android-processor:2.27'

2.概念

1.声明者
如activity中声明，我需要...
class MainActivity : AppCompatActivity() {
    @Inject
    lateinit var cloth: Cloth
    @Inject
    lateinit var cloth1: Cloth1······
    
2.注入器Component
如MainComponent，绑定Module。自定义inject方法，传入声明者。
@Component(modules = [MainModule::class])
interface MainComponent {
    fun inject(mainActivity: MainActivity)
}

3.提供者Module
@Provides自定义的方法，或@Inject构造函数，提供对象

@Module
class MainModule {
    @Provides
    fun b(): Cloth1 {
        val cloth1 = Cloth1("彩色")
        return cloth1
    }
}

data class Cloth constructor(var color: String = "") {
    @Inject
    constructor() : this("构造函数的")

    override fun toString(): String {
        return "${color}布料"
    }
}