Kotlin中使用Dagger2可能遇到的坑解决

apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-kapt'

...

dependencies {
...
 //dagger2 
 compile rootProject.ext.dependencies["dagger"]
 kapt rootProject.ext.apt["dagger-compiler"]

 //dagger2 android 一个dagger2 关于Android的增强库 可选项
 compile rootProject.ext.dependencies["dagger-android"]
 //可选项
 compile rootProject.ext.dependencies["dagger-android-support"]
 //可选项
 kapt rootProject.ext.apt["dagger-android-processor"]
}

@Singleton
@Component(modules = arrayOf(AppModule::class))
interface AppComponent {
 fun inject(app: BaseApplication)
}

@Module
class AppModule(val app: Application) {
 @Provides
 @Singleton
 fun provideApplication() = app
}

class BaseApplication : Application() {

 override fun onCreate() {
  super.onCreate()
  initApplication()
  DaggerCoreComponent
    .builder()
    .coreModule(CoreModule(this))
    .build();
 }
}

class MainActivity : AppCompatActivity() ,MainContract.View {


 @Inject
 var mPresenter : MainContract.Presenter ? = null


 override fun onCreate(savedInstanceState: Bundle?) {
 //******//
 super.onCreate(savedInstanceState)
 DaggerMainActivityComponent.builder().build().inject(this)

 mPresenter?.subscribe()

 }


 @Module
 inner class PresenterModules {

 @Provides
 fun providePresenter(): MainContract.Presenter {
  return MainPresenter(this@MainActivity)
 }
 }
}

@Component(modules = arrayOf(MainActivity.PresenterModules::class))
interface MainActivityComponent {
 fun inject(activity: MainActivity)
}

public final class MainActivity extends AppCompatActivity implements View {
 @Inject
 @Nullable
 private Presenter mPresenter;
-----省略
}

//于是将上述代码改成
 @Inject
 @JvmField
 var mPresenter : MainContract.Presenter ? = null

//或则
@Inject
lateinit mPresenter : MainContract.Presenter

 @Inject
 @JvmField
// @Named("preneter")// 错误 正确的做法如下 
 @field:[Named("preneter")]
 var mPresenter : MainContract.Presenter ? = null

 @Module
 inner class PresenterModules {

 @Provides
 @Named("preneter")
 fun providePresenter(): MainContract.Presenter {
  return MainPresenter(this@MainActivity)
 }

 @Provides
 @Named("hello")
 fun provide():String{
  return "hello"
 }
 }