Currently I'm using Dagger 2 to inject an instance of Retrofit to use for an api call in a widget. From my understanding, Dagger searches for things to inject using the type, so declaring 2 seperate #Provides Retrofit providesRetrofit() with different names wouldn't work.
Heres my current code:
Module:
#Module
public class ApiModule {
#Provides
#Singleton
GsonConverterFactory provideGson() {
return GsonConverterFactory.create();
}
#Provides
#Singleton
RxJavaCallAdapterFactory provideRxCallAdapter() {
return RxJavaCallAdapterFactory.create();
}
#Singleton
#Provides
Retrofit providePictureRetrofit(GsonConverterFactory gsonConverterFactory, RxJavaCallAdapterFactory rxJavaCallAdapterFactory) {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(MarsWeatherWidget.PICTURE_URL)
.addConverterFactory(gsonConverterFactory)
.addCallAdapterFactory(rxJavaCallAdapterFactory)
.build();
return retrofit;
}
....
//Here is the other Retrofit instance where I was wanting to use a different URL.
// #Singleton
// #Provides
// Retrofit provideWeatherRetrofit(GsonConverterFactory gsonConverterFactory, RxJavaCallAdapterFactory rxJavaCallAdapterFactory) {
// Retrofit retrofit = new Retrofit.Builder()
// .baseUrl(MarsWeatherWidget.WEATHER_URL)
// .addConverterFactory(gsonConverterFactory)
// .addCallAdapterFactory(rxJavaCallAdapterFactory)
// .build();
// return retrofit;
// }
}
Component:
#Singleton
#Component(modules = ApiModule.class)
public interface ApiComponent {
void inject (MarsWeatherWidget marsWeatherWidget);
}
class extending Application:
public class MyWidget extends Application {
ApiComponent mApiComponent;
#Override
public void onCreate() {
super.onCreate();
mApiComponent = DaggerApiComponent.builder().apiModule(new ApiModule()).build();
}
public ApiComponent getApiComponent() {
return mApiComponent;
}
}
and finally where im actually injecting it:
#Inject Retrofit pictureRetrofit;
#Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
// There may be multiple widgets active, so update all of them
mAppWidgetIds = appWidgetIds;
((MyWidget) context.getApplicationContext()).getApiComponent().inject(this);
final int N = appWidgetIds.length;
for (int i = 0; i < N; i++) {
updateAppWidget(context, appWidgetManager, appWidgetIds[i]);
}
}
......
//use the injected Retrofit instance to make a call
So how can I organize this to give me a seperate Retrofit instance that is built with different URLs for hitting different APIs? Let me know if more info is needed.
Provide different versions of the same type
You can use #Named (or custom annotations that are annotated with #Qualifier) to distinguish between variants of the same type.
Add the annotations like the following:
#Singleton
#Provides
#Named("picture")
Retrofit providePictureRetrofit(GsonConverterFactory gsonConverterFactory, RxJavaCallAdapterFactory rxJavaCallAdapterFactory) {
return retrofit = new Retrofit.Builder()
.baseUrl(MarsWeatherWidget.PICTURE_URL) // one url
.build();
}
#Singleton
#Provides
#Named("weather")
Retrofit provideWeatherRetrofit(GsonConverterFactory gsonConverterFactory, RxJavaCallAdapterFactory rxJavaCallAdapterFactory) {
return retrofit = new Retrofit.Builder()
.baseUrl(MarsWeatherWidget.WEATHER_URL) // other url
.build();
}
Custom #Qualifier
You could also just create a custom annotation like the following:
#Qualifier
#Retention(RUNTIME)
public #interface Picture {}
You would just use this instead of #Named(String).
Injecting the qualified version
When you have your module providing the qualified types, you just need to also add the qualifier where you need the dependency.
MyPictureService provideService(#Named("picture") Retrofit retrofit) {
// ...
}
You should use a qualifier annotation to distinguish between different objects that have the same type—like between the Retrofit for pictures and the Retrofit for weather.
You apply the same qualifier to the #Provides method and to the #Inject parameter (constructor or method parameter, or field).
#Named is one qualifier annotation, but using it means you have to remember to use the exact same string at the provision point and at all injection points. (It's easy to mistype #Named("whether") somewhere.)
But it's easy to define your own qualifier annotation. Just define a custom annotation type, and annotate that with #Qualifier:
#Documented
#Qualifier
public #interface Picture {}
#Documented
#Qualifier
public #interface Weather {}
Then you can bind each Retrofit differently:
#Provides #Picture Retrofit providePictureRetrofit(…) {…}
#Provides #Weather Retrofit provideWeatherRetrofit(…) {…}
and inject each where you need it:
#Inject #Picture Retrofit pictureRetrofit;
#Inject #Weather Retrofit weatherRetrofit;
// (But constructor injection is better than field injection!)
Related
My field for retrofit in this class is never injected into, it is still null when i run my code.
Here is my ServiceClass where I inject retrofit, have my api calls etc. I stripped it down for simplicity:
public class ServiceClass{
#Inject
Retrofit retrofit;
public ServiceClass(){
}
}
My module class for all network related dependencies:
#Module
public class NetworkModule {
#Provides
#ApplicationScope
Retrofit getRetrofit(OkHttpClient okHttpClient, Gson gson){
return new Retrofit.Builder()
.baseUrl(URL.BASE_URL)
.client(okHttpClient)
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build();
}
#Provides
#ApplicationScope
OkHttpClient getOkHttpClient(Gson gson, HttpLoggingInterceptor httpLoggingInterceptor){
OkHttpClient okHttpClient = new OkHttpClient();
okHttpClient.newBuilder().addInterceptor(httpLoggingInterceptor);
return okHttpClient;
}
#Provides
#ApplicationScope
HttpLoggingInterceptor getHttpLoggingInterceptor(){
return new HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.BASIC);
}
#Provides
#ApplicationScope
Gson getGson(){
return new Gson();
}
}
My AppComponent this is my only component class:
#ApplicationScope
#Component(modules = {NetworkModule.class})
public interface AppComponent {
#Component.Builder
interface Builder {
#BindsInstance
Builder application(MyApplication myApplication);
AppComponent build();
}
void inject(MyApplication myApplication);
Retrofit getRetrofit();
}
My Application class:
public class MyApplication extends Application{
private AppComponent appComponent;
#Override
public void onCreate() {
super.onCreate();
DaggerAppComponent
.builder()
.application(this)
.build()
.inject(this);
}
public AppComponent getAppComponent(){
return appComponent;
}
}
I tried to fiddle around the code, I don't seem to manage to get it working properly. What am I missing here?
Update (previous information still valid) :
I have noticed you incorrectly build your component: you must add .networkModule(new NetworkModule()) after DaggerAppComponent.builder()
Make sure your private AppComponent appComponent is initialized too!
For field injection (I believe that's what you're after), you can write your constructor like this:
public ServiceClass(){
MyApplication.getInstance().getAppComponent().inject(this)
}
Naturally, you should expose your appComponent entity somehow - the above is my guess (to expose appComponent entity via application entity).
PS.: better approach (and more readable too) is to avoid field injection at all and parametrize constructor (however it's not always possible, like for example if you inject into activity).
PSS.: your AppComponent should also have void inject(ServiceClass value);
There are multiple ways of injecting retrofit in ServiceClass
You have to make a separate Component for ServiceClass like :-
#Component(dependencies = AppComponent.class)
interface ServiceClassComponent {
void injectServiceClass(ServiceClass serviceClass);
}
Or
you can just inject ServiceClass into your application component:-
void injectServiceClass(ServiceClass serviceClass);
into your AppComponent
The dependencies keyword would include all the dependent components into your particular component that you would build.
Then in the constructor of ServiceClass you need to build the Component and inject it
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);
}
I create dagger2 module for retrofit2
#Module
public class NetworkModule {
private Context context;
public NetworkModule(Application app) {
this.context = app;
}
#Singleton
#Provides
Context providesContext() {
return context;
}
#Singleton
#Provides
OkHttpClient providesOkHttpClient(Utils utils) {
User user = utils.getSettings();
return new OkHttpClient.Builder()
.connectTimeout(Long.valueOf(user.getTimeOut()), TimeUnit.SECONDS)
.writeTimeout(Long.valueOf(user.getTimeOut()), TimeUnit.SECONDS)
.readTimeout(Long.valueOf(user.getTimeOut()), TimeUnit.SECONDS)
.build();
}
#Singleton
#Provides
Retrofit providesRetrofit(OkHttpClient okHttpClient, Utils utils) {
User user = utils.getSettings();
String host = user.getHost();
if (!host.endsWith("/")) host += "/";
return new Retrofit.Builder()
.baseUrl(host)
.addConverterFactory(JacksonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(okHttpClient).build();
}
#Singleton
#Provides
RestApiFactory providesRestApiFactory(Retrofit retrofit) {
return new RestApiFactory(retrofit);
}
}
I have settings activity where user can change baseUrl, timeOut. If I create
providesRetrofit
providesRestApiFactory
providesOkHttpClient
like #Singleton - after change settings it not change. If I remove #Singleton annotation - all work. My questions - how can I update dagger #Singleton when user change data?
Place NetworkModule in separate component(likely Subcomponent of your main Component) and recreate it when user changes baseUrl, timeout etc.
You can do that by creating interface annotated with #Subcomponent and adding your network module there. You can instantiate this Subcomponent by invoking method from your main component that you also need to add.
Detailed tutorial
https://google.github.io/dagger/subcomponents.html
I am learning Dagger 2 now and it's such a pain for me to explain the question without codes , so let me list all my modules, components and etc first :
App.class
public class App extends Application {
private ApiComponent mApiComponent = null;
private AppComponent mAppComponent = null;
public ApiComponent getApiComponent() {
if (mApiComponent == null) {
// Dagger%COMPONENT_NAME%
mApiComponent = DaggerApiComponent.builder()
// list of modules that are part of this component need to be created here too
.appModule(new AppModule(this)) // This also corresponds to the name of your module: %component_name%Module
.apiModule(new ApiModule(this))
.build();
}
return mApiComponent;
}
public AppComponent getAppComponent() {
if (mAppComponent == null) {
// If a Dagger 2 component does not have any constructor arguments for any of its modules,
// then we can use .create() as a shortcut instead:
mAppComponent = DaggerAppComponent.builder()
.appModule(new AppModule(this))
.build();
}
return mAppComponent;
}
}
AppComponent
#Singleton
#Component(modules = AppModule.class)
public interface AppComponent {
void inject(RetrofitDemo target);
}
AppModule
private final Application mContext;
AppModule(Application context) {
mContext = context;
}
#Singleton
#ForApplication
#Provides
Application provideApplication() {
return mContext;
}
#Singleton
#ForApplication
#Provides
Context provideContext() {
return mContext;
}
ApiComponent
#Singleton
#Component(dependencies = {AppModule.class},modules = {ApiModule.class})
public interface ApiComponent {
void inject(RetrofitDemo target);
}
APIModule
#Inject
Context application;
#Inject
public ApiModule(Context context){
this.application = context;
}
#Provides
#Singleton
Gson provideGson() {
return new GsonBuilder()
// All timestamps are returned in ISO 8601 format:
.setDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'")
// Blank fields are included as null instead of being omitted.
.serializeNulls()
.create();
}
#Provides
#Singleton
OkHttpClient provideOkHttpClient() {
...
}
#Provides
#Singleton
public Retrofit provideRetrofit(Gson gson,OkHttpClient okHttpClient){
return new Retrofit.Builder()
.baseUrl(DribbleApi.END_POINT)
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.client(okHttpClient)
.build();
}
And my activity will be like this:
#Inject
Retrofit mRetrofit;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_retrofit_demo);
((App) getApplication()).getApiComponent().inject(this);
...
Here is the error message:
Error:(18, 10) : retrofit2.Retrofit cannot be provided without an #Inject constructor or from an #Provides- or #Produces-annotated method.
retrofit2.Retrofit is injected at com.sinyuk.yuk.RetrofitDemo.mRetrofit
com.sinyuk.yuk.RetrofitDemo is injected at com.sinyuk.yuk.AppComponent.inject(target)
What makes me confused is the retrofit instance is provided by the ApiModule, but why the error massage said it's injected at appComponent?And I can't find any place wrong in my code. T_T,it's too heavy going to learn Dagger for me...I think.
Besides, in my case I wrote dependencies = AppModule.class module = ApiModule.class in the AppComponent , and it seems to be right I think,but if I wrote module = ({AppComponent.class,ApiComponent.class}),it also works fine.Anybody can explain me why?
Kindly review my code and give me some advice. Thx in advance!
#Sinyuk There's a lot to unpack here, and Dagger is a little complicated at first blush, but I think I can help. First, you have a conceptual misunderstanding regarding the #Component annotation. A Component is an interface which you define, and which Dagger implements through code generation. You will define the interface, and annotate it with #Component and then you will provide a set of Modules to Dagger to use in the generation process. The modules which you use are passed in through the modules element of the #Component annotation. If you want to have one Component permit another Component to support the injection process, then any Component interfaces which you need to have Dagger use while injecting your code, will be passed in through the dependencies element of the #Component annotation.
--
As a result, The following is incorrect
#Component(dependencies = AppModule.class module = ApiModule.class`)
instead, to have the one Component use two Modules write:
#Component(modules = {ApiModule.class, AppModule.class})
or, to have one Component use one Module and depend upon the other Component
#Component(modules = {AppModule.class}, dependencies = {ApiComponent.class})
I hope that that helps you get onto the right path. Let me know if you have any follow up questions.
Okay so your configuration should be this
public class App extends Application {
private AppComponent mAppComponent = null;
public AppComponent getAppComponent() {
if (mAppComponent == null) {
// If a Dagger 2 component does not have any constructor arguments for any of its modules,
// then we can use .create() as a shortcut instead:
mAppComponent = DaggerAppComponent.builder()
.appModule(new AppModule(this))
.build();
}
return mAppComponent;
}
}
And
#Singleton
#Component(modules = {AppModule.class, ApiModule.class})
public interface AppComponent {
void inject(RetrofitDemo target);
}
And
#Module
public class AppModule {
private final Application mContext;
AppModule(Application context) {
mContext = context;
}
#Provides
Application provideApplication() {
return mContext;
}
#Provides
Context provideContext() {
return mContext;
}
}
And
#Module
public class ApiModule {
#Provides
#Singleton
Gson provideGson() {
return new GsonBuilder()
// All timestamps are returned in ISO 8601 format:
.setDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'")
// Blank fields are included as null instead of being omitted.
.serializeNulls()
.create();
}
#Provides
#Singleton
OkHttpClient provideOkHttpClient() {
...
}
#Provides
#Singleton
public Retrofit provideRetrofit(Gson gson, OkHttpClient okHttpClient){
return new Retrofit.Builder()
.baseUrl(DribbleApi.END_POINT)
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.client(okHttpClient)
.build();
}
}
And
//...Activity
#Inject
Retrofit mRetrofit;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_retrofit_demo);
((App) getApplication()).getAppComponent().inject(this);
...
I have this network module . I want to inject Network module in static method of ErrorUtils.
#Module
public class NetworkModule {
private final String END_POINT = "https://www.myurl.com/";
#Provides
#Singleton
public OkHttpClient getOkHttpClient() {
OkHttpClient okHttpClient = builder.build();
return okHttpClient;
}
#Provides
#Singleton
public GsonConverterFactory getGsonConverterFactory() {
return GsonConverterFactory.create();
}
#Provides
#Singleton
public Retrofit getRetrofit(OkHttpClient okHttpClient, GsonConverterFactory gsonConverterFactory) {
return new Retrofit.Builder()
.baseUrl(END_POINT)
.client(okHttpClient)
.addConverterFactory(gsonConverterFactory)
.build();
}
#Provides
#Singleton
public RetrofitService getRetrofitService(Retrofit retrofit) {
return retrofit.create(RetrofitService.class);
}
And I want to inject this module in static method as :
public class ErrorUtils {
#Inject
static Retrofit retrofit;
public static RestError parseError(Response<?> response) {
**//showing error while writing this line**
MyApplication.getComponent().inject(ErrorUtils.class);
Converter<ResponseBody, RestError> converter = retrofit.responseBodyConverter(RestError.class, new Annotation[0]);
RestError error;
try {
error = converter.convert(response.errorBody());
} catch (IOException e) {
return new RestError();
}
return error;
}
}
How can we inject module in static method ,any suggestion ?
As can be seen in Migrating from Dagger 1
Dagger 2 does not support static injection.
Static methods and variables are generally a bad idea. In your case you could just make your ErrorUtils an object, e.g. with #Singleton scope. Then you could properly inject the service and also properly inject your errorUtils without the use of static calls.
If that is not an option, you can just provide a getter to your component
#Component interface MyComponent {
Retrofit getRetrofit();
}
And then use that method to set your static variable.