Dagger Android for custom class possible?

Question

I am trying to make dagger-android work with Conductor (or any custom class). I tried replicating everything that AndroidSupportInjectionModule (and friends) do, which in my mind is the same kind of a custom class handling.

However I get

C:\Users\ursus\AndroidStudioProjects\...\ControllersModule.java:15: error: com.foo.bar.ChannelsController is not a framework type
    public abstract com.foo.bar.ChannelsController channelsController();

So, my "library" code

package com.foo.bar

import com.bluelinelabs.conductor.Controller;
import dagger.Module;
import dagger.android.AndroidInjectionModule;
import dagger.android.AndroidInjector;
import dagger.internal.Beta;
import dagger.multibindings.Multibinds;

import java.util.Map;

@Beta
@Module(includes = AndroidInjectionModule.class)
public abstract class ConductorInjectionModule {

    private ConductorInjectionModule() {
    }

    @Multibinds
    abstract Map<Class<? extends Controller>, AndroidInjector.Factory<? extends Controller>> controllerInjectorFactories();

    @Multibinds
    abstract Map<String, AndroidInjector.Factory<? extends Controller>> controllerInjectorFactoriesWithStringKeys();
}

I dont even get compiled, so presuming pasting ConductorInjection & HasControllerInjector is pointless

Usage:

@Module
abstract class AppModule {
    @ContributesAndroidInjector abstract fun mainActivity(): MainActivity
    @ContributesAndroidInjector abstract fun channelsController(): ChannelsController
}

class App : Application(), HasActivityInjector, HasControllerInjector {

    @Inject lateinit var activityInjector: DispatchingAndroidInjector<Activity>
    @Inject lateinit var controllerInjector: DispatchingAndroidInjector<Controller>

    private lateinit var appComponent: AppComponent

    override fun onCreate() {
        super.onCreate()

        appComponent = DaggerAppComponent.builder()
            .applicationContext(this)
            .build()
            .apply {
                inject(this@App)
            }
    }

    override fun activityInjector() = activityInjector
    override fun controllerInjector() = controllerInjector
}

@Singleton
@Component(
    modules = [
        AndroidInjectionModule::class,
        ConductorInjectionModule::class,
        AppModule::class,
        NetModule::class
    ]
)
interface AppComponent {

    fun inject(app: App)

    @Component.Builder
    interface Builder {

        @BindsInstance
        fun applicationContext(context: Context): Builder

        fun build(): AppComponent
    }
}


implementation deps.dagger.runtime
implementation deps.dagger.androidRuntime
kapt deps.dagger.compiler
kapt deps.dagger.androidCompiler

where it is all "2.19" version (have tried 2.16)

AGP "com.android.tools.build:gradle:3.3.0-rc02" (have tried 3.2.1 stable)

Any clue? In my mind it all should work as its the same thing dagger-android-support does

Answer 1

error: com.foo.bar.ChannelsController is not a framework type

So the question to answer is, "how does dagger-android know what a framework type is or not".

The answer can be found in this commit to Dagger-Android between 2.19 and 2.20, where they "removed the old way of doing things for better compatibility with AndroidX".

So as we can see in https://stackoverflow.com/a/53891780/2413303 ,

   /**    
    * Returns the Android framework types available to the compiler, keyed by their associated {@code 
    * dagger.android} {@link MapKey}s. This will always contain the types that are defined by the 
    * framework, and only contain the support library types if they are on the classpath of the   
    * current compilation.    
    */    
   static ImmutableMap<Class<? extends Annotation>, TypeMirror> frameworkTypesByMapKey(   
       Elements elements) {   
     return ImmutableMap.copyOf(  
         Stream.of(   
                 elements.getPackageElement("dagger.android"),    
                 elements.getPackageElement("dagger.android.support"))    
             .filter(packageElement -> packageElement != null)    
             .flatMap(packageElement -> typesIn(packageElement.getEnclosedElements()).stream())   
             .filter(AndroidMapKeys::isNotAndroidInjectionKey)    
             .filter(type -> isAnnotationPresent(type, MapKey.class)) 
             .filter(mapKey -> mapKey.getAnnotation(MapKey.class).unwrapValue())  
             .flatMap(AndroidMapKeys::classForAnnotationElement)  
             .collect(toMap(key -> key, key -> mapKeyValue(key, elements)))); 
   }

they had code that checked their own @MapKey types in dagger.android and dagger.android.support packages, that looked like this:

// java/dagger/android/support/FragmentKey.java

 @Beta  
 @MapKey    
 @Documented    
 @Target(METHOD)    
 @Deprecated    
 public @interface FragmentKey {    
   Class<? extends Fragment> value();   
 }

So they read the framework types based on what @MapKeys were available in the dagger.android and dagger.android.support packages.

---

Apparently they removed this check in 2.20 so now you can inject whatever you want. Rejoice!

But otherwise you could actually hack it in such a way that you'd add a @ControllerKey and a @ViewKey in dagger.android package in your project, and it'd actually likely work with 2.19.

The tests that were checking for errors in "is not a framework type" are also removed in that commit.

Ah, and

@Multibinds
abstract Map<String, AndroidInjector.Factory<? extends Controller>> controllerInjectorFactoriesWithStringKeys();

You can remove this part too with 2.20, all you need now is AndroidInjectionModule.

Answer 2

For future travelers, they were hardcoding some appcompat stuff in the annot. processor, thats why appcompat fragments worked.

update to dagger 2.20, it will magically work