I just started learning dagger2 and faced a strange issue that looks like a bug to me. Here's the module:
@Module
public class SimpleModule {
@Provides
Cooker providerCooker() {
return new Cooker("tom", "natie");
}
}
Component:
@Component(modules = SimpleModule.class)
public interface SimpleComponent {
void inject(DaggerTestActivity activity);
}
Interface:
public interface CoffeeMaker {
String makeCoffee();
}
Implementation:
public class SimpleMaker implements CoffeeMaker {
Cooker mCooker;
@Inject
public SimpleMaker(Cooker cooker) {
this.mCooker = cooker;
}
@Override
public String makeCoffee() {
return mCooker.makeCoffee();
}
}
Cooker :
public class Cooker {
String name;
String coffeeKind;
public Cooker(String name, String coffeeKind) {
this.name = name;
this.coffeeKind = coffeeKind;
}
public String makeCoffee() {
return name + "make" + coffeeKind;
}
}
Coffee machine:
public class CoffeeMachine {
CoffeeMaker mMaker;
@Inject
public CoffeeMachine(CoffeeMaker coffeeMaker) {
this.mMaker = coffeeMaker;
}
public String makeCoffee() {
return mMaker.makeCoffee();
}
}
Just it. I use it in the activity. Faced strange issue here:
@Inject
CoffeeMachine mCoffeeMachine;
The error I'm getting from the Dagger 2 compiler is the following:
Error:(14, 10) com.wyyc.daggertest.CoffeeMaker cannot be provided without an @Provides-annotated method.
com.wyyc.zqqworkproject.DaggerTestActivity.mCoffeeMachine
[injected field of type: com.wyyc.daggertest.CoffeeMachine mCoffeeMachine]
com.wyyc.daggertest.CoffeeMachine.<init>(com.wyyc.daggertest.CoffeeMaker coffeeMaker)
All this situation looks very strange, and I'd like to hear some input from more experienced Dagger 2 users.
Your CoffeeMachine needs CoffeeMaker. And you have declared that Dagger will take care of providing that dependency to the CoffeeMachine by annotating the constructor with @Inject. But Dagger says:
CoffeeMaker cannot be provided without an @Provides-annotated method
Because you haven't specified anywhere how CoffeeMaker object should be created. @Injecting SimpleMaker is not enough, because SimpleMaker != CoffeeMaker. So, you have to specify explicitly, that when Dagger wants CoffeeMaker then provide him SimpleMaker.
Change your module to this:
@Module
public class SimpleModule {
@Provides
Cooker providerCooker() {
return new Cooker("tom", "natie");
}
@Provides
CoffeeMaker provideCoffeeMaker(Cooker cooker) {
return new SimpleMaker(cooker);
}
}
In my case I missed one module in @Component (in multi-module app). Thanks to @azizbekian.
@Component(
modules = [
ApiModule::class,
SettingsModule::class,
CoroutinesModule::class // <- I forgot one of these modules
],
dependencies = [Api::class, NetworkProvider::class]
)
interface YourComponent {