Dagger 2 component not generated

问题

In my module, in my base Application class

component = DaggerCompClassComponent.builder()
                .classModule(new ModuleClass()).build();

it can not find DaggerCompClassComponent.

I have on module build.gradle

apply plugin: 'com.neenbedankt.android-apt'
.........................
apt 'com.google.dagger:dagger-compiler:2.8'
compile 'com.google.dagger:dagger:2.8'
provided 'javax.annotation:jsr250-api:1.0'

and in Project build.gradle,

 classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'

I have done build / rebuild / clean / restart project. I have a Component class where I inject objects and a ModuleClass where I provide objects to inject.

What can be the cause for not generating Dagger Component . class ?

EDIT:

This is my ModuleClass, adnotated with @Module:

@Provides
@Singleton
public Interceptor provideInterceptor() {
    return new Interceptor() {
        @Override
        public Response intercept(Chain chain) throws IOException {
            Request.Builder builder = chain.request().newBuilder();

            builder.addHeader("AppName-Android", BuildConfig.VERSION_NAME + "-" + BuildConfig.VERSION_CODE)
                    .addHeader("Content-Type", "application/json");

            return chain.proceed(builder.build());
        }
    };
}

@Provides
@Singleton
OkHttpClient provideOkHttpClient(Interceptor interceptor) {
    OkHttpClient.Builder builder = new OkHttpClient.Builder();
    builder.interceptors().add(interceptor);
    return builder.build();
}

@Provides
@Singleton
Retrofit provideRetrofit(OkHttpClient client) {
    return new Retrofit.Builder()
            .baseUrl(BaseApplication.getRes().getString(R.string.api_base_url))
            .addConverterFactory(GsonConverterFactory.create())
            .client(client)
            .build();
}

@Provides
@Singleton
WebServiceCall provideWebService(Retrofit retrofit) {
    return retrofit.create(WebServiceCall.class);
}

And this is my Component Class:

@Component(modules = ModuleClass.class)
@Singleton
public interface ComponentClass {

    void inject(Interceptor o);
    void inject(OkHttpClient o);
    void inject(Retrofit o);
    void inject(WebServiceCall o);

}

回答1:

When developing on Kotlin, you should add the following lines next to their annotationProcessor counterparts:

kapt 'com.google.dagger:dagger-android-processor:2.15'
kapt 'com.google.dagger:dagger-compiler:2.15'

and add apply plugin: 'kotlin-kapt' at the start of the same file.

That section looks like this for me:

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-kapt' // <- Add this line
apply plugin: 'io.fabric'

回答2:

Here is the solution for the fresh Dagger project.

These two lines are responsible to generate the compile-time framework in Dagger 2.

compile 'com.google.dagger:dagger:2.14.1'//generates framework in compile timeannotationProcessor 'com.google.dagger:dagger-compiler:2.14.1' //generates framework in compile time based on the annotations you provided.

Full setup Dagger

        //dagger 2
        compile 'com.google.dagger:dagger:2.14.1'
        annotationProcessor 'com.google.dagger:dagger-compiler:2.14.1'

        //to enable DaggerActivity, DaggerBroadcastReceiver, DaggerFragment etc classes
        compile 'com.google.dagger:dagger-android:2.14.1'
        annotationProcessor 'com.google.dagger:dagger-android-processor:2.14.1'

        //support libraries with dagger 2
        compile 'com.google.dagger:dagger-android-support:2.14.1'

Note: You need to configure Annotation Process as provided in the screenshot below. You can do this File>Other Settings>Default Settings>search"Annotation processor"

回答3:

Maybe you forgot to annotate ModuleClass with @Module ?

回答4:

There are some minor misconceptions/faults in your code above, here's a working implementation:

Application.java:

component = DaggerComponentClass.builder().classModule(new ModuleClass()).build();

The generated class will be named DaggerComponentClass, not DaggerCompClassComponent. If you can't run your app in Android Studio to get it built, try Build->Clean project and Build->Rebuild project in the menu. If everything is OK Dagger will have compiled DaggerComponentClass which will be located in the same package as ComponentClass.

ComponentClass.java:

@Component(modules = ModuleClass.class)
public interface ComponentClass {
    void inject(AClassThatShouldGetInstancesInjected instance);
}

A Component in Dagger2 has methods named inject that receive the instance to get instances injected into it, not the other way around. In the code above the class AClassThatShouldGetInstancesInjected will typically call componentClass.inject(this); to get instances injected into itself.

ModuleClass.java:

@Module
public class ModuleClass {
    @Provides
    @Singleton
    public Interceptor provideInterceptor() {/*code*/}

    //Your Providers...
}

The Module is correct in your code, make sure its annotated.

回答5:

If you have several modules in your AndroidStudio (modules in terms of Android Studio, not Dagger), another possible reason of fail is that you've forgot to put annotation processors into the all modules' build.gradle.

We've divided our app into several modules, updated dependencies from using implementation to using api but forgot to handle annotation processors accordingly.

So, you can have this lines only in a root module:

api 'com.google.dagger:dagger-android:2.16'
// if you use the support libraries
api 'com.google.dagger:dagger-android-support:2.16'

But this ones should be specified in all modules dependencies:

annotationProcessor 'com.google.dagger:dagger-compiler:2.16'
// if you use injections to Android classes
annotationProcessor 'com.google.dagger:dagger-android-processor:2.16'

回答6:

In build.gradle's app, you need to add necessary dependencies for Dagger to generate corresponding classes, as below:

  implementation 'com.google.dagger:dagger-android:2.21'
  implementation 'com.google.dagger:dagger-android-support:2.21' // if you use the support libraries
  annotationProcessor 'com.google.dagger:dagger-android-processor:2.21'
  annotationProcessor 'com.google.dagger:dagger-compiler:2.21'

you should change dagger version which you are using.

refer full dagger document in this

回答7:

If you are using Kotlin, make sure to add kapt (Kotlin annotation processor) Gradle plugin to your build script and use kapt Gradle dependency type instead of annotationProcessor for Dagger Compiler.

apply plugin: 'kotlin-kapt

kapt deps.daggercompiler
implementation deps.dagger

回答8:

If Dagger2 can not generate its components it means that your code have some errors with Scopes/Modules. Check our your @Provides/Inject methods.

UPD:

You should inject your components into cases where you need instances of classes provided by module.

inject(MainActivity main);

回答9:

//add all the dependencies otherwise component class will not be generated.
implementation 'com.google.dagger:dagger-android:2.21'
implementation 'com.google.dagger:dagger-android-support:2.21'
annotationProcessor 'com.google.dagger:dagger-android-processor:2.21'
implementation 'com.google.dagger:dagger:2.21'
annotationProcessor 'com.google.dagger:dagger-compiler:2.21'

来源：https://stackoverflow.com/questions/43756498/dagger-2-component-not-generated

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android

dagger