Ituoke Ajanlekoko Ituoke Ajanlekoko - 2 months ago 18
Android Question

Dependency Injection Into Service

I am trying to

inject dependencies
into my App. Everything is working fine until I tried to inject
Realm
into my
Service
class. I started getting
IllegalStateException
which is obviously caused by me accessing
Realm
from a
Thread
it was created. So, this is the structure of my
Dependency Injection


The AppModule

@Module
public class AppModule {

MainApplication mainApplication;

public AppModule(MainApplication mainApplication) {
this.mainApplication = mainApplication;
}

@Provides
@Singleton
MainApplication getFmnApplication() {
return mainApplication;
}
}


The RequestModule

@Module
public class RequestModule {

@Provides
@Singleton
Retrofit.Builder getRetrofitBuilder() {
return new Retrofit.Builder()
.baseUrl(BuildConfig.HOST)
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create(CustomGsonParser.returnCustomParser()));
}

@Provides
@Singleton
OkHttpClient getOkHttpClient() {
return new OkHttpClient.Builder()
.addInterceptor(new HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.BASIC))
.connectTimeout(30000, TimeUnit.SECONDS)
.readTimeout(30000, TimeUnit.SECONDS).build();
}

@Provides
@Singleton
Retrofit getRetrofit() {
return getRetrofitBuilder().client(getOkHttpClient()).build();
}

@Provides
@Singleton
ErrorUtils getErrorUtils() {
return new ErrorUtils();
}

@Provides
@Singleton
MainAPI getMainAPI() {
return getRetrofit().create(MainAPI.class);
}

// Used in the Service class
@Provides
@Singleton
GeneralAPIHandler getGeneralAPIHandler(MainApplication mainApplication) {
return new GeneralAPIHandler(mainApplication, getMainAPIHandler(), getErrorUtils());
}
}


The AppComponent

@Singleton
@Component(modules = {
AppModule.class,
RequestModule.class
})
public interface MainAppComponent {

void inject(SyncService suncService);
}


The Application Class

public class MainApplication extends Application {

private MainAppComponent mainAppComponent;

@Override
protected void attachBaseContext(Context base) {
super.attachBaseContext(base);
MultiDex.install(this);
}

@Override
public void onCreate() {
super.onCreate();
mainAppComponent = DaggerMainAppComponent.builder()
.appModule(new AppModule(this))
.requestModule(new RequestModule())
.build();
}

public MainAppComponent getMainAppComponent() {
return mainAppComponent;
}
}


GeneralAPIHandler

public class GeneralAPIHandler {

private static final String TAG = "GeneralAPIHandler";
private MainAPI mainAPI;
private Realm realm;
private ErrorUtils errorUtils;
private Context context;

public GeneralAPIHandler() {
}

public GeneralAPIHandler(MainApplication mainApplication, MainAPI mainAPI, ErrorUtils errorUtils) {
this.mainAPI = mainAPI;
this.realm = RealmUtils.getRealmInstance(mainApplication.getApplicationContext());
this.errorUtils = errorUtils;
this.context = mainApplication.getApplicationContext();
}

public void sendPayload(APIRequestListener apiRequestListener) {
List<RealmLga> notSentData = realm.where(RealmLga.class).equalTo("isSent", false).findAll(); <-- This is where the error comes from

.... Other code here
}
}


This only happens when I'm calling it from a
Service class
But, it was created with the Application Context. Why is it throwing an
IllegalStateException


The Service Class

public class SyncService extends IntentService {

@Inject GeneralAPIHandler generalAPIHandler;

@Override
public void onCreate() {
super.onCreate();
((MainApplication) getApplicationContext()).getMainAppComponent().inject(this);
}

/**
* Creates an IntentService. Invoked by your subclass's constructor.
*/
public SyncService() {
super("Sync");
}

@Override
protected void onHandleIntent(Intent intent) {
sendInformations();
}

private void sendInformations() {
generalAPIHandler.sendPayload(new APIRequestListener() {
@Override
public void onError(APIError apiError){}

@Override
public void didComplete(WhichSync whichSync){}
})
}
}


Any help on what I'm doing wrong to be making
Realm
throw
IllegalStateException
would be appreciated. Thanks

Answer
@Inject GeneralAPIHandler generalAPIHandler;

@Override
public void onCreate() {
    super.onCreate();
    ((MainApplication) getApplicationContext()).getMainAppComponent().inject(this);
}

And therefore

public GeneralAPIHandler(MainApplication mainApplication, MainAPI mainAPI, ErrorUtils errorUtils) {
    this.mainAPI = mainAPI;
    this.realm = RealmUtils.getRealmInstance(mainApplication.getApplicationContext()); // <--

This code runs on the UI thread


@Override
protected void onHandleIntent(Intent intent) {
    sendInformations();
}

private void sendInformations() {
    generalAPIHandler.sendPayload(new APIRequestListener() {
    ....


public void sendPayload(APIRequestListener apiRequestListener) {
    List<RealmLga> notSentData = realm.where(RealmLga.class).equalTo("isSent", false).findAll();

This code runs on the IntentService background thread

You also wouldn't be closing the Realm instance despite being on a non-looping background thread anyways, so it did you a favor by crashing.


Solution, you should obtain Realm instance in onHandleIntent(), and close it in finally { at the end of execution.


You might say, "but then how will I mock my Constructor argument", the answer is use a class like

@Singleton
public class RealmFactory {
    @Inject
    public RealmFactory() {
    }

    public Realm create() {
        return Realm.getDefaultInstance();
    }
}