We Keep Coding

inheritance and generic and Dagger2

I have two kind of fragment. One of them is ListFragment and the other one is ListWithFilterFragment that ListWithFilterFragment extend ListFragment. Also I have two presenter for these fragments that ListWithFilterPresenter extend ListPresenter. So I define separate module for presenter and separate component in Dagger. I want to inject correct presenter to these fragment but I got error
this is ListFragment:
public class ListFragment<V extends ListView> extends BaseFragment<V, ListPresenter<V>> implements ListView {
#Inject
ListPresenter presenter;
#NonNull
#Override
public ListPresenter createPresenter() {
DaggerListComponent.builder().build().inject((ListFragment<ListView>) this);
return presenter;
}
this is ListWithFilterFragment:
public class ListWithFilterFragment extends ListFragment<ListWithFilterView> implements ListWithFilterView {
#Inject
ListWithFilterPresenter presenter;
#NonNull
#Override
public ListWithFilterPresenter createPresenter() {
DaggerListWithFilterComponent.builder().build().inject(this);
return presenter;
}
}
this is ListComponent:
#Singleton
#Component(modules = {ListPresenterModule.class,
ListInteractorModule.class})
public interface ListComponent {
void inject(ListFragment<ListView> fragment);
}
this is ListWithFilterComponent:
#Singleton
#Component(modules = {ListWithFilterPresenterModule.class,
ListInteractorModule.class})
public interface ListWithFilterComponent {
void inject(ListWithFilterFragment fragment);
}
and my presenters modules
#Module
public class ListWithFilterPresenterModule {
#Provides #NonNull #Singleton
public ListWithFilterPresenter providePresenter(ListInteractor interactor) {
return new ListWithFilterPresenter(interactor);
}
}
#Module
public class ListPresenterModule {
#Provides #NonNull #Singleton
public ListPresenter providePresenter(ListInteractor interactor) {
return new ListPresenter(interactor);
}
}
Error:(16, 10) error: com.sober.appModules.List.presenter.ListPresenter cannot be provided without an #Provides- or #Produces-annotated.method.com.sober.appModules.List.presenter.ListPresenter is injected at
com.sober.appModules.List.ui.ListFragment.presenter
com.sober.appModules.List.ui.ListWithFilterFragment is injected at com.sober.appModules.List.injection.ListWithFilterComponent.inject(fragment)

Dagger does not do partial injections. Either it can provide all the objects, or it will fail with cannot be provided.
In your case ListWithFilterComponent cannot provide ListPresenter to ListWithFilterFragment—or rather its ListFragment parent.
see comments at the end of the lines
error: List.presenter.ListPresenter cannot be provided without an #Provides- or #Produces-annotated.method.
List.presenter.ListPresenter is injected at <- missing object
List.ui.ListFragment.presenter <- field in parent that is getting injected
List.ui.ListWithFilterFragment is injected at <- object it tries to inject
List.injection.ListWithFilterComponent.inject(fragment) <- component that's missing something
If you want to keep your current setup you will need to provide ListPresenter from your ListWithFilterComponent as well, or otherwise you will need to refactor your fragments so that they don't extend one another.

Using AndroidInjections contribution module (abstract class) as subcomponent in Dagger 2

I study Dagger 2 and try to understand how I can attach it to an already existing project. Now I faced with the following problem with injectiing dependencies into BroadcastReceivers. I can't use DaggerReceiver because my receivers already extends another class. To use AndroidInjection inside BroadcastReceivers, I should inject DispatchingAndroidInjector to Application class. I don't want to include module with AndroidInjection contributors to main dependency graph so, how I understand, I should place it to dedicated component for Application class, but because of this duplication of Singletons occurs.
Here is my example (GitHub repo)
Classes to provide dependencies to MainActivity and other classes
AppModule.class
#Module
public class AppModule {
Application mApplication;
public AppModule(Application application) {
mApplication = application;
}
#Singleton
#Provides
Application providesApplication() {
return mApplication;
}
}
UtilityModule.class
#Module
public class UtilityModule {
#Singleton
#Provides
FirstUtilityClass providesFirstUtility(Application app) {
return new FirstUtilityClass(app);
}
#Singleton
#Provides
SecondUtilityClass providesSecondUtility(Application app) {
return new SecondUtilityClass(app);
}
}
MainComponent.class
#Singleton
#Component(modules = { AppModule.class, UtilityModule.class })
public interface MainComponent {
void inject(MainActivity activity);
}
Classes to provide DispatchingAndroidInjector to Application class
ReceiversModule.class
#Module
public abstract class ReceiversModule {
#ContributesAndroidInjector
abstract FirstReceiver contributesFirstReceiver();
#ContributesAndroidInjector
abstract SecondReceiver contributesSecondReceiver();
}
ReceiversComponent.class
#Singleton
#Component(modules = { AppModule.class, UtilityModule.class, ReceiversModule.class })
public interface ReceiversComponent {
void inject(MyApplication application);
}
Injecting...
MyApplication.class
public class MyApplication extends Application implements HasBroadcastReceiverInjector {
#Inject DispatchingAndroidInjector<BroadcastReceiver> mInjector;
#Inject FirstUtilityClass mFirstUtility;
#Inject SecondUtilityClass mSecondUtility;
MainComponent mMainComponent;
#Override
public void onCreate() {
AppModule appModule = new AppModule(this);
mMainComponent = DaggerMainComponent.builder().appModule(appModule).build();
// I should build new component only for Application class, because DispatchingAndroidInjector not required for another targets
DaggerReceiversComponent.builder().appModule(appModule).build().inject(this); // Here created new scope
super.onCreate();
// do something
mFirstUtility.doFistThings(getClass().getSimpleName());
mSecondUtility.doSecondThings(getClass().getSimpleName());
}
public MainComponent getMainComponent() {
return mMainComponent;
}
#Override
public AndroidInjector<BroadcastReceiver> broadcastReceiverInjector() {
return mInjector;
}
}
MainActivity.class
public class MainActivity extends AppCompatActivity {
#Inject FirstUtilityClass mFirstUtility;
#Inject SecondUtilityClass mSecondUtility;
#Override
protected void onCreate(Bundle savedInstanceState) {
((MyApplication) getApplication()).getMainComponent().inject(this);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Do something
mFirstUtility.doFistThings(getClass().getSimpleName());
mSecondUtility.doSecondThings(getClass().getSimpleName());
// Sending broadcasts here
}
}
Logcat output
FirstUtilityClass1: doing first things from MyApplication...
SecondUtilityClass1: doing second things from MyApplication...
FirstUtilityClass2: doing first things from MainActivity...
SecondUtilityClass2: doing second things from MainActivity...
FirstUtilityClass1: doing first things from FirstReceiver...
SecondUtilityClass1: doing second things from SecondReceiver...
How you see in log, Apllication and MainActivity receives different instances of utility classes. I had an idea to make ReceiversComponent as a subcomponent of MainComponent. But ReceiversModule is abstract and I cant add it dinamicaly to existed component instance.
MainComponent.class
#Singleton
#Component(modules = { AppModule.class, UtilityModule.class })
public interface MainComponent {
ReceiversComponent with(ReceiversModule module);
void inject(MainActivity activity);
}
ReceiversComponent.class
#Subcomponent(modules = { ReceiversModule.class })
public interface ReceiversComponent {
void inject(MyApplication application);
}
And then in MyApplication:
// It does not work because I can't create ReceiverModule instance :(
mMainComponent.with(new ReceiversModule()).inject(this);
How can I use the ReceiversComponent as a subcomponent of MainComponent?
It's clear to me that I'm doing something wrong, but I just can't understand where. Maybe there is another way to solve my problem?

I just found the answer!
Since my ReceiversModule class has a default constructor without parameters, I can skip it as parameter when describing the subcomponent in MainComponent interface:
MainComponent.class
#Singleton
#Component(modules = { AppModule.class, UtilityModule.class })
public interface MainComponent {
ReceiversComponent withReceiversModule(); // Here is the reference to the subcomponent with abstract module
void inject(MainActivity activity);
}
MyApplication.class
#Override
public void onCreate() {
AppModule appModule = new AppModule(this);
mMainComponent = DaggerMainComponent.builder().appModule(appModule).build();
mMainComponent.withReceiversModule().inject(this); // It's works!!! :)
super.onCreate();
// do something
mFirstUtility.doFistThings(getClass().getSimpleName());
mSecondUtility.doSecondThings(getClass().getSimpleName());
}
Maybe someone will think it is a trifle, but it took me several days to reach it. I'm very happy, because my code has become a little cleaner. Thanks to all!

Dagger 2 single instance of MyClass

I'm trying to refactor my code so I was thinking about Dagger2 to solve my issues. I've created AppComponent to store all of my Singletons:
#AppScope
#Component(
modules = {
AppModule.class,
// more here...
}
)
public interface AppComponent {
Context exposeContext();
CmdComponent newCmdComponent(CmdModule module);
// ... few injections here
}
My AppModule:
#Module
public class AppModule {
private Context context;
public AppModule(Context context) {
this.context = context;
}
// ... provide appContext etc.
#AppScope #Provides
MyClass provideMyClass() {
Log.i("DAGGER", "provideMyClass: ");
return new MyClass();
}
}
I inject this in my Application class:
public class App extends Application {
private static AppComponent component;
#Override
public void onCreate() {
super.onCreate();
component = DaggerAppComponent.builder()
.appModule(new AppModule(app))
.build();
}
public static AppComponent getAppComponent() {
return component;
}
}
Then I have my subcomponent CmdComponent with different #Scope
#CmdScope
#Subcomponent(
modules = {
CmdModule.class
}
)
public interface CmdComponent {
void inject(Cmd cmd);
}
Now I'm injecting dependancies into my Cmd instance like:
#Inject MyClass myClass;
public Cmd() {
App.getAppComponent()
.newCmdComponent(new CmdModule())
.inject(this);
}
Unfortunetly log: Log.i("DAGGER", "provideMyClass: "); and log inside MyClass constructor are shown multiple times... so I get new instance of MyClass every time. How to tell Dagger to give me the same instance (created once) every time?

Ok. I solve my issue. The solution is simple. My AppScope was created wrong. For some reason, I thought that annotation works like inheritance.
My custom annotation was like:
#Singleton
#Retention(RetentionPolicy.RUNTIME)
public #interface AppScope {
}
and Dagger thought that my component is unscoped.. It should be like:
#Scope
#Retention(RetentionPolicy.RUNTIME)
public #interface AppScope {
}

How about the .newCmdComponent(new CmdModule()). Why do you do that, creating a new module every time? The component already has a module attached, you've set that on creation of the component.

Dagger 2 LocalDataSource cannot be provided without #Provides annotated method

I'm trying to follow the same example as in here by creating a Repository pattern with DI.
The problem is that I get the following error:
"Error:(16, 20) error: #mvp.model.di.scope.Local
mvp.model.repository.local.GameLocalDataSource cannot be provided
without an #Provides-annotated method. #mvp.model.di.scope.Local
mvp.model.repository.local.GameLocalDataSource is injected at
mvp.model.repository.GameRepository.(gameLocalDataSource, …)
mvp.model.repository.GameRepository is provided at
mvp.model.di.component.RepositoryComponent.getGameRepository()"
Here's the code related to the app:
public class GameApplication extends Application {
private RepositoryComponent repositoryComponent;
#Override
public void onCreate() {
super.onCreate();
if (LeakCanary.isInAnalyzerProcess(this)) {
// This process is dedicated to LeakCanary for heap analysis.
// You should not init your app in this process.
return;
}
LeakCanary.install(this);
// Normal app init code...
repositoryComponent = DaggerRepositoryComponent.builder()
.applicationModule(new ApplicationModule((getApplicationContext())))
.build();
}
public RepositoryComponent getRepositoryComponent() {
return repositoryComponent;
}
}
This is my RepositoryComponent:
#Singleton
#Component(modules = {RepositoryModule.class, ApplicationModule.class})
public interface RepositoryComponent {
GameRepository getGameRepository();
}
Here's the RepositoryModule:
#Module
public class RepositoryModule {
#Singleton
#Provides
#Local
GameDataSource provideLocalDataSource(Context context) {
return new GameLocalDataSource(context);
}
#Singleton
#Provides
#Remote
GameDataSource provideRemoteDataSource() {
return new GameRemoteDataSource();
}
}
And finally, the ApplicationModule:
#Module
public final class ApplicationModule {
private Context context;
public ApplicationModule(Context context) {
this.context = context;
}
#Provides
Context providesContext() {
return context;
}
}
Here's most of my GameRepository class:
#Singleton
public class GameRepository implements GameDataSource {
private GameDataSource remoteDataSource;
private GameDataSource localDataSource;
#Inject
public GameRepository(#Local GameLocalDataSource gameLocalDataSource, #Remote GameRemoteDataSource gameRemoteDataSource) {
remoteDataSource = gameRemoteDataSource;
localDataSource = gameLocalDataSource;
}
Also, as in the mentioned example, I created a couple of scopes, #Local and #Remote since my two data sources have the same type and Dagger needs to differentiate them.
#Qualifier
#Documented
#Retention(RetentionPolicy.RUNTIME)
public #interface Local {
}
The rest of the code I have related to dagger, is just the #Inject in the constructors where I want to inject my dependencies.
Also, the DaggerRepositoryComponent is never generated in the GameApplication class.
Thanks a lot for the help in advance!

GameLocalDataSource cannot be provided without an #Provides-annotated method
Somewhere in the code you are trying to #Inject GameLocalDataSource, but you have specified in your module how to provide GameDataSource, not GameLocalDataSource.
...
GameDataSource provideLocalDataSource(Context context) {
return new GameLocalDataSource(context);
}
...
Either ask Dagger to inject GameDataSource, or describe Dagger how to provide GameLocalDataSource.
...
GameLocalDataSource provideLocalDataSource(Context context) {
return new GameLocalDataSource(context);
}
...

how to use injection between MVP layers in android?

I have been using using dagger 2 in my project lately,
the problem is when I try to build my project, the presenter in my login
activity which injected like below is null,
and when I try to build the project
presenter cannot be provided without an #Inject constructor or from an #Provides- or #Produces-annotated method...
I don't understand what have I done wrong??, please someone help me with this,
thanks in advance.
Here is my Login Activity, the presenter here is null, which shows that, I've not injected it properly
#Inject
LoginPresenter presenter;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
InjectHelper.getRootComponent().injectPresenter(this);
presenter.setProgressBarVisiblity(View.INVISIBLE);
}
this is my presenter module
#Module
public class PresenterModule {
private final LoginActivity activity;
public PresenterModule(LoginActivity activity) {
this.activity = activity;
}
#Provides
#Singleton
public LoginActivity providesView() {
return activity;
}
}
#Provides
#Singleton
public LoginPresenter providesPresenter()
{
return new LoginPresenter();
}
}
this inject helper class
public class InjectHelper {
private static RootComponent sRootComponent;
static {
initModules();
}
private static void initModules() {
sRootComponent = getRootComponentBuilder().build();
}
public static DaggerRootComponent.Builder getRootComponentBuilder() {
return DaggerRootComponent.builder();
}
public static RootComponent getRootComponent() {
if (sRootComponent == null) {
initModules();
}
return sRootComponent;
}
}
this is root component class
#Singleton
#Component(modules = {
PresenterModule.class
})
public interface RootComponent {
void injectLoginView(LoginPresenter loginPresenter);
}

you need to inform the dagger which views want to use injection, in your component.
you must change the inject function code in your component to below:
void inject(LoginActivity activity);
for showing dagger what you want, you need to use #dagger annotation NOT by sending it as inject function in component file. as you did properly:
#Inject
LoginPresenter presenter;
Dagger will search for a variable of type LoginPresenter in your module and finds the proper provider method using the type.
what you put in your component as a argument for "inject" function tells the Dagger what view you are going to do injection in (NOT what you want to inject)

#Singleton
#Component(modules = {PresenterModule.class})
public interface RootComponent {
void inject(LoginActivity activity);
}