android - 我如何使用 Kodein 进行注入(inject)？

Question

我刚刚学习了用于依赖注入(inject)的kodein lib。我如何获取变量的依赖值？我在下面的应用程序类中，我将上下文与 kodein 绑定(bind):

class BaseApp : Application(), KodeinAware {
    override val kodein by Kodein.lazy {
        import(contextModule)
    }

    private val contextModule = Kodein.Module(CONTEXT_MODULE_TAG){
        bind<Context>(CONTEXT_TAG) with provider { this@BaseApp }
    }

    companion object{
        private const val CONTEXT_MODULE_TAG = "context_module"
        const val CONTEXT_TAG = "context_tag"
    }
}

在我的存储库类中，我尝试获取上下文，但没有成功。

class BatteryRepository : KodeinAware {
    override val kodein by kodein()
    private val context by instance<Context>(BaseApp.CONTEXT_TAG)
...

其中kodein()方法调用错误:

Expression 'kodein' cannot be invoked as a function. The function 'invoke()' is not found

我如何获取上下文？像这样传输上下文是个好主意吗？

Answer 1

我遇到了同样的问题。原来我错过了这个依赖项 import org.kodein.di.android.x.kodein (不知道为什么它没有被 IDE 自动添加)

这是 Kodein + AndroidX 库的示例:AndroidManifest.xml

<application
        ...
        android:name=".core.BaseApplication">

申请

open class BaseApplication : Application(), KodeinAware {
    override val kodein = Kodein.lazy {
        import(androidXModule(this@BaseApplication))

        // import(otherCustomModule)
    }
}

fragment

import androidx.fragment.app.Fragment
import org.kodein.di.Kodein
import org.kodein.di.KodeinAware
import org.kodein.di.android.x.kodein
import org.kodein.di.generic.kcontext

abstract class InjectionFragment : Fragment(), KodeinAware {

    final override val kodeinContext = kcontext<Fragment>(this)
    final override val kodein: Kodein by kodein()


    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        kodeinTrigger?.trigger()
    }
}

// usage
class MyFragment() : InjectionFragment() {
    val someDependency: Type by instance()
}

依赖app\build.gradle

implementation "org.kodein.di:kodein-di-generic-jvm:6.3.2"
implementation "org.kodein.di:kodein-di-framework-android-x:6.3.2"
implementation "androidx.appcompat:appcompat:1.0.2"

额外覆盖 kodeinTrigger 属性(来自 KodeinAware)也是值得的。这样，当创建 Fragment 时，所有用于 debug 构建的依赖项都将被解析，因此应用程序将立即失败(与 release 构建相反，其中依赖项仅在使用时被解析- 某些用户路径可能不会使应用程序崩溃)

abstract class InjectionFragment : Fragment(), KodeinAware {

    final override val kodeinContext = kcontext<Fragment>(this)
    final override val kodein: Kodein by kodein()
    final override val kodeinTrigger: KodeinTrigger? // See description in InjectionActivity
        get() = if (BuildConfig.DEBUG) KodeinTrigger() else super.kodeinTrigger

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        kodeinTrigger?.trigger()
    }
}

编辑:这是我的项目，所有东西都连接在一起 https://github.com/igorwojda/Android-Showcase