I have Hilt DI framework in my Android project. Also I have retrofit, and ApiNetworkModule for getting singleton retrofit object:
#Module
#InstallIn(SingletonComponent.class)
public class ApiNetworkModule {
...
#Singleton
#Provides
public Retrofit provideRetrofit(
OkHttpClient okHttpClient,
Gson gson,
SharedPrefManager sharedPrefManager
) {
return new Retrofit.Builder()
.client(okHttpClient)
.baseUrl(sharedPrefManager.getUrl())
.addConverterFactory(GsonConverterFactory.create(gson))
.build();
}
...
}
In general it works fine, but I have noticed in the case when url is updated in sharedPrefManager, retrofit object does not know about it and uses old url. It will be fully updated only after closing-opening application. Is there any way how to reinit Retrofit singleton programmatically? Or how to handle it correctly?
I'm learning about retrofit interceptors, for work purposes I'm using dagger-hilt for the injection of dependencies to fragments etc. I wrote a custom interceptor to check for connection errors and I'm trying to add it to the Retrofit.Builder():
#Provides
#Singleton
fun provideApi(): StoreApi {
return Retrofit.Builder()
.baseUrl(Constants.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava3CallAdapterFactory.create())
.build()
.create(StoreApi::class.java)
}
however, I have no clue how to pass that:
val okHttpClient = OkHttpClient()
.newBuilder()
.addInterceptor(ConnectivityInterceptor)
.build()
as a .client() to the retofit builder (even with dagger-hilt), any ideas?
You can setup a module something like this where you provide all the dependency requirements as functions and exposing them to dagger through #Provides then leave dagger to provide the dependencies as function arguments to build the dependency graph :
#Module class ApiModule {
#Provides
#Singleton
internal fun provideApi(retrofit: Retrofit): StoreApi {
return retrofit
.create(StoreApi::class.java)
}
#Provides
#Singleton
internal fun retrofit(client: OkHttpClient): Retrofit =
Retrofit.Builder()
.client(client)
.baseUrl(Constants.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava3CallAdapterFactory.create())
.build()
#Provides
#Singleton
internal fun client(connectivityInterceptor: ConnectivityInterceptor): OkHttpClient =
OkHttpClient.Builder()
.addInterceptor(connectivityInterceptor)
.build()
#Provides
#Singleton
internal fun interceptor(): ConnectivityInterceptor = ConnectivityInterceptor()
}
This is a trivial example based on the supplied code.
I am new to Hilt and have negligible experience in Dagger 2 as well.
I am now doing a simple sample project for my self-learning, and trying to apply Hilt.
I use Retrofit to call APIs.
So, I am trying to refactor my code into using Hilt:
#Module
#InstallIn(SingletonComponent::class)
object WeatherAPIModule {
private const val BASE_URL = "https://api.openweathermap.org/data/2.5/"
#Provides
fun provideHttpLoggingInterceptor(): HttpLoggingInterceptor {
return HttpLoggingInterceptor().apply {
level = HttpLoggingInterceptor.Level.BODY
}
}
#Provides
fun provideOkHttpClient(loggingInterceptor: HttpLoggingInterceptor): OkHttpClient {
return OkHttpClient.Builder()
.addInterceptor(loggingInterceptor)
.build()
}
#Provides
fun provideGsonConverterFactory(): GsonConverterFactory {
return GsonConverterFactory.create()
}
#Provides
fun provideRetrofit(okHttpClient: OkHttpClient, gsonConverterFactory: GsonConverterFactory): Retrofit {
return Retrofit.Builder()
.baseUrl(BASE_URL)
.client(okHttpClient)
.addConverterFactory(gsonConverterFactory)
.build()
}
#Provides
fun provideWeatherService(retrofit: Retrofit): OpenWeatherService {
return retrofit.create(OpenWeatherService::class.java)
}
val weatherApiKey by lazy {
ApiKeyStore.getWeatherApiKey()
}
}
My question is, Should I use #Provides on Base URL and API Key as well?
Why do I ask
According to my understanding, if I have a class like this:
class SomeClass #Inject constructor() {
#Inject lateinit var someString: String
...
}
Hilt will try to find modules that provides String, and inject that String here. But clearly that's not what I want.
What should be the best way to do this?
Especially for weatherApiKey. I think I should not have leave it as an ordinary function, because that would lose the point of using Hilt at all.
I'm following the new Dagger2 support for android to implement a movies list sample application and below is my use case.
Activity Holds a fragment used to load list of movies
Fragment uses a presenter to hit an api using retrofit
Presenter has a dependency to the API interface class which contains Observale for the movies
I'm using #Inject inside the presenter for the ApiService interface but i got an error that i cannot use #Inject field without declaring provide annotation and below is my code
Main App component
My Movies module
My Movies Contract
My Presenter
and finally the api service interface
So how can i provide the service interface to MoviesModule in order to work properly inside the presenter
The error is
Error:(22, 8) error: [dagger.android.AndroidInjector.inject(T)] sampler.dagger.com.movieslist.data.MoviesApiService cannot be provided without an #Provides-annotated method.
sampler.dagger.com.movieslist.data.MoviesApiService is injected at
sampler.dagger.com.movieslist.movies.MoviePresenter.mApiService
sampler.dagger.com.movieslist.movies.MoviePresenter is injected at
sampler.dagger.com.movieslist.movies.MoviesModule.moviesPresenter(presenter)
sampler.dagger.com.movieslist.movies.MoviesContract.Presenter is injected at
sampler.dagger.com.movieslist.movies.MoviesFragment.mPresenter
dagger.Lazy<sampler.dagger.com.movieslist.movies.MoviesFragment> is injected at
sampler.dagger.com.movieslist.movies.MainActivity.mMoviesFragmentsProvider
sampler.dagger.com.movieslist.movies.MainActivity is injected at
dagger.android.AndroidInjector.inject(arg0)
One solution could be:
#Module
public class APIModule {
#Provides
#Singleton
Retrofit provideRetrofit(Gson gson) {
OkHttpClient client = new OkHttpClient.Builder().build();
return new Retrofit.Builder()
.baseUrl("https://stackoverflow.com/")
.addConverterFactory(GsonConverterFactory.create(gson))
.client(client)
.build();
}
#Provides
#Singleton
Gson provideGson() {
return new GsonBuilder().create();
}
#Provides
#Singleton
MoviesApiService provideMoviesApiService(Retrofit retrofit) {
return retrofit.create(MoviesApiService.class);
}
}
In your MoviePresenter its better to use constructor injection than field injection:
private MoviesApiService mApiService;
#Inject
public MoviePresenter(MoviesApiService apiService) {
mApiService = apiService;
}
MoviApiService is an interface, you cannot inject an interface. You need to create a provides method to provide the retrofit service.
MoviApiService providesMoviApiService(Retrofit retrofit) {
retrofit.create(MoviApiService.class);
}
Hey there I am using Dagger2, Retrofit and OkHttp and I am facing dependency cycle issue.
When providing OkHttp :
#Provides
#ApplicationScope
OkHttpClient provideOkHttpClient(TokenAuthenticator auth,Dispatcher dispatcher){
return new OkHttpClient.Builder()
.connectTimeout(Constants.CONNECT_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(Constants.READ_TIMEOUT,TimeUnit.SECONDS)
.writeTimeout(Constants.WRITE_TIMEOUT,TimeUnit.SECONDS)
.authenticator(auth)
.dispatcher(dispatcher)
.build();
}
When providing Retrofit :
#Provides
#ApplicationScope
Retrofit provideRetrofit(Resources resources,Gson gson, OkHttpClient okHttpClient){
return new Retrofit.Builder()
.baseUrl(resources.getString(R.string.base_api_url))
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(okHttpClient)
.build();
}
When providing APIService :
#Provides
#ApplicationScope
APIService provideAPI(Retrofit retrofit) {
return retrofit.create(APIService.class);
}
My APIService interface :
public interface APIService {
#FormUrlEncoded
#POST("token")
Observable<Response<UserTokenResponse>> refreshUserToken();
--- other methods like login, register ---
}
My TokenAuthenticator class :
#Inject
public TokenAuthenticator(APIService mApi,#NonNull ImmediateSchedulerProvider mSchedulerProvider) {
this.mApi= mApi;
this.mSchedulerProvider=mSchedulerProvider;
mDisposables=new CompositeDisposable();
}
#Override
public Request authenticate(Route route, Response response) throws IOException {
request = null;
mApi.refreshUserToken(...)
.subscribeOn(mSchedulerProvider.io())
.observeOn(mSchedulerProvider.ui())
.doOnSubscribe(d -> mDisposables.add(d))
.subscribe(tokenResponse -> {
if(tokenResponse.isSuccessful()) {
saveUserToken(tokenResponse.body());
request = response.request().newBuilder()
.header("Authorization", getUserAccessToken())
.build();
} else {
logoutUser();
}
},error -> {
},() -> {});
mDisposables.clear();
stop();
return request;
}
My logcat :
Error:(55, 16) error: Found a dependency cycle:
com.yasinkacmaz.myapp.service.APIService is injected at com.yasinkacmaz.myapp.darkvane.modules.NetworkModule.provideTokenAuthenticator(…, mApi, …)
com.yasinkacmaz.myapp.service.token.TokenAuthenticator is injected at
com.yasinkacmaz.myapp.darkvane.modules.NetworkModule.provideOkHttpClient(…, tokenAuthenticator, …)
okhttp3.OkHttpClient is injected at
com.yasinkacmaz.myapp.darkvane.modules.NetworkModule.provideRetrofit(…, okHttpClient)
retrofit2.Retrofit is injected at
com.yasinkacmaz.myapp.darkvane.modules.NetworkModule.provideAPI(retrofit)
com.yasinkacmaz.myapp.service.APIService is provided at
com.yasinkacmaz.myapp.darkvane.components.ApplicationComponent.exposeAPI()
So my question: My TokenAuthenticator class is depends on APIService but I need to provide TokenAuthenticator when creating APIService. This causes dependency cycle error. How do I beat this , is there anyone facing this issue ?
Thanks in advance.
Your problem is:
Your OKHttpClient depends on your Authenticator
Your Authenticator depends on a Retrofit Service
Retrofit depends on an OKHttpClient (as in point 1)
Hence the circular dependency.
One possible solution here is for your TokenAuthenticator to depend on an APIServiceHolder rather than a APIService. Then your TokenAuthenticator can be provided as a dependency when configuring OKHttpClient regardless of whether the APIService (further down the object graph) has been instantiated or not.
A very simple APIServiceHolder:
public class APIServiceHolder {
private APIService apiService;
#Nullable
APIService apiService() {
return apiService;
}
void setAPIService(APIService apiService) {
this.apiService = apiService;
}
}
Then refactor your TokenAuthenticator:
#Inject
public TokenAuthenticator(#NonNull APIServiceHolder apiServiceHolder, #NonNull ImmediateSchedulerProvider schedulerProvider) {
this.apiServiceHolder = apiServiceHolder;
this.schedulerProvider = schedulerProvider;
this.disposables = new CompositeDisposable();
}
#Override
public Request authenticate(Route route, Response response) throws IOException {
if (apiServiceHolder.get() == null) {
//we cannot answer the challenge as no token service is available
return null //as per contract of Retrofit Authenticator interface for when unable to contest a challenge
}
request = null;
TokenResponse tokenResponse = apiServiceHolder.get().blockingGet()
if (tokenResponse.isSuccessful()) {
saveUserToken(tokenResponse.body());
request = response.request().newBuilder()
.header("Authorization", getUserAccessToken())
.build();
} else {
logoutUser();
}
return request;
}
Note that the code to retrieve the token should be synchronous. This is part of the contract of Authenticator. The code inside the Authenticator will run off the main thread.
Of course you will need to write the #Provides methods for the same:
#Provides
#ApplicationScope
apiServiceHolder() {
return new APIServiceHolder();
}
And refactor the provider methods:
#Provides
#ApplicationScope
APIService provideAPI(Retrofit retrofit, APIServiceHolder apiServiceHolder) {
APIService apiService = retrofit.create(APIService.class);
apiServiceHolder.setAPIService(apiService);
return apiService;
}
Note that mutable global state is not usually a good idea. However, if you have your packages organised well you may be able to use access modifiers appropriately to avoid unintended usages of the holder.
Using the Lazy interface of Dagger 2 is the solution here.
In your TokenAuthenticator replace APIService mApi with Lazy<APIService> mApiLazyWrapper
#Inject
public TokenAuthenticator(Lazy<APIService> mApiLazyWrapper,#NonNull ImmediateSchedulerProvider mSchedulerProvider) {
this.mApiLazyWrapper= mApiLazyWrapper;
this.mSchedulerProvider=mSchedulerProvider;
mDisposables=new CompositeDisposable();
}
And to get the APIService instance from wrapper use mApiLazyWrapper.get()
In case mApiLazyWrapper.get() returns null, return null from the authenticate method of TokenAuthenticator as well.
Big thanks to #Selvin and #David. I have two approach, one of them is David's answer and the other one is :
Creating another OkHttp or Retrofit or another library which will handle our operations inside TokenAuthenticator class.
If you want to use another OkHttp or Retrofit instance you must use Qualifier annotation.
For example :
#Qualifier
public #interface ApiClient {}
#Qualifier
public #interface RefreshTokenClient {}
then provide :
#Provides
#ApplicationScope
#ApiClient
OkHttpClient provideOkHttpClientForApi(TokenAuthenticator tokenAuthenticator, TokenInterceptor tokenInterceptor, Dispatcher dispatcher){
return new OkHttpClient.Builder()
.connectTimeout(Constants.CONNECT_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(Constants.READ_TIMEOUT,TimeUnit.SECONDS)
.writeTimeout(Constants.WRITE_TIMEOUT,TimeUnit.SECONDS)
.authenticator(tokenAuthenticator)
.addInterceptor(tokenInterceptor)
.dispatcher(dispatcher)
.build();
}
#Provides
#ApplicationScope
#RefreshTokenClient
OkHttpClient provideOkHttpClientForRefreshToken(Dispatcher dispatcher){
return new OkHttpClient.Builder()
.connectTimeout(Constants.CONNECT_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(Constants.READ_TIMEOUT,TimeUnit.SECONDS)
.writeTimeout(Constants.WRITE_TIMEOUT,TimeUnit.SECONDS)
.dispatcher(dispatcher)
.build();
}
#Provides
#ApplicationScope
#ApiClient
Retrofit provideRetrofitForApi(Resources resources, Gson gson,#ApiClient OkHttpClient okHttpClient){
return new Retrofit.Builder()
.baseUrl(resources.getString(R.string.base_api_url))
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(okHttpClient)
.build();
}
#Provides
#ApplicationScope
#RefreshTokenClient
Retrofit provideRetrofitForRefreshToken(Resources resources, Gson gson,#RefreshTokenClient OkHttpClient okHttpClient){
return new Retrofit.Builder()
.baseUrl(resources.getString(R.string.base_api_url))
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(okHttpClient)
.build();
}
Then we can provide our seperated interfaces :
#Provides
#ApplicationScope
public APIService provideApi(#ApiClient Retrofit retrofit) {
return retrofit.create(APIService.class);
}
#Provides
#ApplicationScope
public RefreshTokenApi provideRefreshApi(#RefreshTokenClient Retrofit retrofit) {
return retrofit.create(RefreshTokenApi.class);
}
When providing our TokenAuthenticator :
#Provides
#ApplicationScope
TokenAuthenticator provideTokenAuthenticator(RefreshTokenApi mApi){
return new TokenAuthenticator(mApi);
}
Advantages : You have two seperated api interfaces which means you can maintain them independently. Also you can use plain OkHttp or HttpUrlConnection or another library.
Disadvantages : You will have two different OkHttp and Retrofit instance.
P.S : Make sure you make syncronous calls inside Authenticator class.
You can inject the service dependency into your authenticator via the Lazy type. This way you will avoid the cyclic dependency on instantiation.
Check this link on how Lazy works.