Dagger 2 在Android中的使用——Fragment篇

Dagger2_with_android_part2_1.kt

/**
 * author: jixiaoyong
 * email: jixiaoyong1995@gmail.com
 * website: https://jixiaoyong.github.io
 * date: 2019/1/27
 * description: 这里演示的是将Fragment加入到AppComponent中；
 将将Fragment加入到Activity中Dagger2官方文档有，不再赘述
 详见：https://google.github.io/dagger/android
 */

@Component(modules = [AndroidInjectionModule::class, MainActivityModule::class, MainFragmentModule::class])
interface AppComponent {

    fun inject(application: MainApplication)
}

@Subcomponent
interface MainActivitySubComponent : AndroidInjector<MainActivity> {

    @Subcomponent.Builder
    abstract class Builder : AndroidInjector.Builder<MainActivity>()

}

@Module(includes = [MainActivityModule.InnerModule::class], subcomponents = [MainActivitySubComponent::class])
class MainActivityModule {

    @Provides
    fun bindWaitForInjectClass() = WaitForInjectClass()

    @Module
    abstract class InnerModule {
        @Binds
        @IntoMap
        @ClassKey(MainActivity::class)
        abstract fun bindInjectorFactory(builder: MainActivitySubComponent.Builder): AndroidInjector.Factory<*>
    }
}


@Subcomponent
interface MainFragmentSubComponent : AndroidInjector<MainFragment> {

    @Subcomponent.Builder
    abstract class Builder : AndroidInjector.Builder<MainFragment>()

}

@Module(includes = [MainFragmentModule.InnerModule::class], subcomponents = [MainFragmentSubComponent::class])
class MainFragmentModule {

    //注意，如果本例中保留了Activity的实例，为了避免同一个@Subcomponent有相同的@Provides方法，我们这里返回另外一个类的实例
    @Provides
    fun bindWaitForInjectClass() = WaitForInjectClassForFragment()

    @Module
    abstract class InnerModule {
        @Binds
        @IntoMap
        @ClassKey(MainFragment::class)
        abstract fun bindInjectorFactory(builder: MainFragmentSubComponent.Builder): AndroidInjector.Factory<*>
    }
}

class WaitForInjectClass
class WaitForInjectClassForFragment

Dagger2_with_android_part2_2.kt

/**
 * author: jixiaoyong
 * email: jixiaoyong1995@gmail.com
 * website: https://jixiaoyong.github.io
 * date: 2019/1/27
 * description: todo
 */
class MainApplication : HasFragmentInjector, Application() {


    override fun onCreate() {
        super.onCreate()
        DaggerAppComponent.create().inject(this)
    }

    @Inject
    lateinit var dispatchingFragmentInject: DispatchingAndroidInjector<Fragment>

    override fun fragmentInjector() = dispatchingFragmentInject
}

Dagger2_with_android_part2_3.kt

/**
 * author: jixiaoyong
 * email: jixiaoyong1995@gmail.com
 * website: https://jixiaoyong.github.io
 * date: 2019/1/27
 * description: 需要将本MainFragment添加到一个Activity中，
 对应的Activity和布局文件等省略
 */
class MainFragment : Fragment() {

    @Inject
    lateinit var waitForInjectClass: WaitForInjectClassForFragment

    override fun onAttach(context: Context?) {
        AndroidInjection.inject(this)
        super.onAttach(context)

        Log.d("TAG", "Fragment class is $waitForInjectClass")

    }

    override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return inflater?.inflate(R.layout.fragment_dagger2_android_main, container, false)
    }
}