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Dagger 2.2 component builder module method deprecated

I started using dagger 2.2 and the module methods in the Component builder are deprecated.
This is my Application component :
#Component(modules = ApplicationModule.class)
public interface ApplicationComponent {
void inject(Application application);
}
And the Application module:
#Module
public class ApplicationModule {
Application application;
public ApplicationModule(Application application) {
this.application = application;
}
#Provides
#Singleton
Application providesApplication() {
return application;
}
}
Here is the generated class:
#Generated(
value = "dagger.internal.codegen.ComponentProcessor",
comments = "https://google.github.io/dagger"
)
public final class DaggerApplicationComponent implements ApplicationComponent {
private DaggerApplicationComponent(Builder builder) {
assert builder != null;
}
public static Builder builder() {
return new Builder();
}
public static ApplicationComponent create() {
return builder().build();
}
#Override
public void inject(Application application) {
MembersInjectors.<Application>noOp().injectMembers(application);
}
public static final class Builder {
private Builder() {}
public ApplicationComponent build() {
return new DaggerApplicationComponent(this);
}
/**
* #deprecated This module is declared, but an instance is not used in the component. This method is a no-op. For more, see https://google.github.io/dagger/unused-modules.
*/
#Deprecated
public Builder applicationModule(ApplicationModule applicationModule) {
Preconditions.checkNotNull(applicationModule);
return this;
}
}
}
How do I initialize the component if not with the ComponentBuilder?

You should read the description of why it is deprecated. If you are using an IDE like IntelliJ or Android Studio you can just select the method and hit Control + Q on Windows to read the Javadoc including the deprecation notice.
The Javadoc reads:
#deprecated This module is declared, but an instance is not used in the component. This method is a no-op. For more, see https://google.github.io/dagger/unused-modules.
And from this link you can see:
When the Dagger processor generates components, it only requires instances of modules and component dependencies that are explicitly needed to supply requests for a binding.
If all of a module’s methods that are used in the component are static, Dagger does not need an instance of that module at all. Dagger can invoke the static methods directly without a module.
If a module provides no bindings for a Component, no instance of that module is necessary to construct the graph.
It is safe to say that you can just ignore the deprecation. It is intended to notify you of unused methods and modules. As soon as you actually require / use Application somewhere in your subgraph the module is going to be needed, and the deprecation warning will go away.

It show deprecated because you are not using Component and module in your application by
#Inject
SomeObjectFromModule mSomeObject
if you are not injecting dependencies in your applications there is no use of initialising your component so dagger look for at least one usage
once you add these lines in any classes you want to inject views and then clean build and rebuild the project and your deprecation will be solved

It showing error when my Module have no #Provides method or the object that provide by Dagger is not used in app.
Example to remove deprecated module
Module
#Module
public class SecondActivityModule {
#Provides
Book provideBookTest() {
return new Book();
}
}
Activity
public class SecondActivity extends AppCompatActivity {
#Inject
Book test;
...
}
OR in Component
#Component(modules = SecondModule.class)
public interface SecondComponent {
void inject(SecondActivity activity);
Book getBookTest();
}

I have the same problem with host and I just want everyone has deprecated issue on Generated component builder class should check two things to save time:
1/ Correct dagger syntax for module, component also check carefully where you inject.
2/ Must have injection object (inject annotation and its object) in place you want to inject or else the dagger compiler cannot see where to use your module so some method will be deprecated.Just inject at least one module's provides to your injection place and re-compile the code, you won't have that issue anymore :)

you will get module method deprecated if you declare void inject(AppCompactActivity activity); in component class. instead of you have to use tight coupling like following void inject(MainActivity activity);and rebuild your project you will see, there is no deprecate method in module class

How can I replace Activity scoped dependencies with mocks using Dagger2

I have a scoped dependency in my Activity and I want to test that activity with some mocks. I have read about different approach that suggest to replace Application component with a test component during the test, but what I want is to replace the Activity component.
For example, I want to test the Activity against mock presenter in my MVP setup.
I believe that replacing component by calling setComponent() on Activity will not work, because Activity dependencies already injected via field injection, so during the test, real object will be used.
How can I resolve this issue? What about Dagger1? Is it has the same issue?

Injecting the Component
First, you create a static class to act as a factory for your Activity. Mine looks a little like this:
public class ActivityComponentFactory {
private static ActivityComponentFactory sInstance;
public static ActivityComponentFactory getInstance() {
if(sInstance == null) sInstance = new ActivityComponentFactory();
return sInstance;
}
#VisibleForTesting
public static void setInstance(ActivityComponentFactory instance) {
sInstance = instance;
}
private ActivityComponentFactory() {
// Singleton
}
public ActivityComponent createActivityComponent() {
return DaggerActivityComponent.create();
}
}
Then just do ActivityComponentFactory.getInstance().createActivityComponent().inject(this); inside your Activities.
For testing, you can replace the factory in your method, before the Activity is created.
Providing mocks
As #EpicPandaForce's answer makes clear, doing this the officially-supported way currently involves a lot of boilerplate and copy/pasted code. The Dagger 2 team need to provide a simpler way of partially overriding Modules.
Until they do though, here's my unnoficial way: Just extend the module.
Let's say you want to replace your ListViewPresenter with a mock. Say you have a PresenterModule which looks like this:
#Module #ActivityScope
public class PresenterModule {
#ActivityScope
public ListViewPresenter provideListViewPresenter() {
return new ListViewPresenter();
}
#ActivityScope
public SomeOtherPresenter provideSomeOtherPresenter() {
return new SomeOtherPresenter();
}
}
You can just do this in your test setup:
ActivityComponentFactory.setInstance(new ActivityComponentFactory() {
#Override
public ActivityComponent createActivityComponent() {
return DaggerActivityComponent.builder()
.presenterModule(new PresenterModule() {
#Override
public ListViewPresenter provideListViewPresenter() {
// Note you don't have to use Mockito, it's just what I use
return Mockito.mock(ListViewPresenter.class);
}
})
.build();
}
});
...and it just works!
Note that you don't have to include the #Provides annotation on the #Override method. In fact, if you do then the Dagger 2 code generation will fail.
This works because the Modules are just simple factories - the generated Component classes take care of caching instances of scoped instances. The #Scope annotations are used by the code generator, but are irrelevant at runtime.

You cannot override modules in Dagger2 [EDIT: you can, just don't specify the #Provides annotation on the mock), which would obviously be the proper solution: just use the builder().somethingModule(new MockSomethingModule()).build() and be done with it!
If you thought mocking is not possible, then I would have seen two possible solutions to this problem. You can either use the modules to contain a pluggable "provider" that can have its implementation changed (I don't favor this because it's just too verbose!)
public interface SomethingProvider {
Something something(Context context);
}
#Module
public class SomethingModule {
private SomethingProvider somethingProvider;
public SomethingModule(SomethingProvider somethingProvider) {
this.somethingProvider = somethingProvider;
}
#Provides
#Singleton
public Something something(Context context) {
return somethingProvider.something(context);
}
}
public class ProdSomethingProvider implements SomethingProvider {
public Something something(Context context) {
return new SomethingImpl(context);
}
}
public class TestSomethingProvider implements SomethingProvider {
public Something something(Context context) {
return new MockSomethingImpl(context);
}
}
SomethingComponent somethingComponent = DaggerSomethingComponent.builder()
.somethingModule(new SomethingModule(new ProdSomethingProvider()))
.build();
Or you can bring the provided classes and injection targets out into their own "metacomponent" interface, which your ApplicationComponent and your TestApplicationComponent extend from.
public interface MetaApplicationComponent {
Something something();
void inject(MainActivity mainActivity);
}
#Component(modules={SomethingModule.class})
#Singleton
public interface ApplicationComponent extends MetaApplicationComponent {
}
#Component(modules={MockSomethingModule.class})
#Singleton
public interface MockApplicationComponent extends MetaApplicationComponent {
}
The third solution is to just extend the modules like in #vaughandroid 's answer. Refer to that, that is the proper way of doing it.
As for activity scoped components... same thing as I mentioned here, it's just a different scope, really.

I've found the following post that solves the problem:
http://blog.sqisland.com/2015/04/dagger-2-espresso-2-mockito.html
You need first to allow to modify the component of the activity:
#Override public void onCreate() {
super.onCreate();
if (component == null) {
component = DaggerDemoApplication_ApplicationComponent
.builder()
.clockModule(new ClockModule())
.build();
}
}
public void setComponent(DemoComponent component) {
this.component = component;
}
public DemoComponent component() {
return component;
}
And modify it in the test case
#Before
public void setUp() {
Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
DemoApplication app
= (DemoApplication) instrumentation.getTargetContext().getApplicationContext();
TestComponent component = DaggerMainActivityTest_TestComponent.builder()
.mockClockModule(new MockClockModule())
.build();
app.setComponent(component);
component.inject(this);
}

Dagger2: Make parent component dependency accessible for subscoped component

I have the following setup:
#ApplicationScope
#Component(
dependencies = {AppContextComponent.class, CertUtilsComponent.class, ServiceComponent.class, JobManagerComponent.class})
public interface ApplicationComponent
extends AppContextComponent, CertUtilsComponent, ServiceComponent, JobManagerComponent {
void inject(MainActivity mainActivity); //honestly, I won't need this
}
And I have the following subscoped component:
#PresenterScope
#Component(dependencies = {ApplicationComponent.class, PersistenceComponent.class})
public interface PresenterComponent
extends ApplicationComponent, PersistenceComponent {
void inject(HomePresenter homePresenter);
void inject(SendCertificateRequestInteractor sendCertificateRequestInteractor);
}
The problem is that PersistenceComponent has the following component as its dependency:
#Component(dependencies = {JobManagerComponent.class, RealmComponent.class, RepositoryComponent.class}, modules = {PersisterModule.class})
public interface PersisterComponent {
DummyCertPersister dummyCertPersister();
}
Which uses JobManagerComponent, which is the dependency of the ApplicationComponent.
Unfortunately, this component does not seem to be inherited from ApplicationComponent. I need to explicitly keep track of this component, and provide it for the builder like so.
//INJECTOR
ApplicationComponent applicationComponent = DaggerApplicationComponent.builder()
.appContextComponent(appContextComponent)
.certUtilsComponent(certUtilsComponent)
.jobManagerComponent(jobManagerComponent)
.serviceComponent(serviceComponent)
.build();
this.jobManagerComponent = jobManagerComponent;
this.applicationComponent = applicationComponent;
this.certUtilsComponent = certUtilsComponent;
this.appContextComponent = appContextComponent;
this.serviceComponent = serviceComponent;
}
public ApplicationComponent getApplicationComponent() {
return applicationComponent;
}
public JobManagerComponent getJobManagerComponent() {
return jobManagerComponent;
}
And provide this through a getter when I build my persistence component:
PersisterComponent persisterComponent = DaggerPersisterComponent.builder()
.jobManagerComponent(Injector.INSTANCE.getJobManagerComponent()) //this should be subcomponent
.realmComponent(realmComponent)
.repositoryComponent(repositoryComponent)
.persisterModule(new PersisterModule())
.build();
I would like to have that JobManagerComponent inherited from ApplicationComponent. I'm guessing I need to make this into a #Subcomponent and provide a provision method for it, but so far, it hasn't worked (I don't get a builder method, but it still doesn't see the jobManager within JobManagerComponent.
Is this possible with #Subcomponent? Or do I need to keep track of the "subcomponents" of ApplicationComponent in case a child component depends on it?

The answer is that I was conceptually wrong about how Components work in Dagger2.
A component should only depend on another component if it subscopes that component. A component with multiple component dependencies cannot depend on scoped components; which means they cannot have scoped modules; which also means they cannot use scopes at all and unless the module keeps a reference to the new instance, you'll get a new instance each time you inject. Which is bad, and not what you want at all.
The proper way is to bind every module of the same scope to the same component. That way, the provided dependencies are accessible within the constructors, and you won't have an issue with sharing the same module within different components as well.
Therefore, the approach in the question is completely wrong.
Use this instead.

how can I inject a dependency in a method?

I'm a beginner with dependency injection.. specifically Dagger 2. I'm trying to figure out if/how I can do something like this:
#Inject
public void someMethodName(int someInteger, SomeObject dependency){
// do something with the dependency.
}
Or do I need to put that dependency in as a class var? any help with this would be greatly appreciated. also in this case the variable someInteger is not a dependency, but is being added by the caller... does that matter?
can I call it like this:
this.someMethodName(5);
android studio does not like the above calling method (I'm assuming because I'm doing something wrong)

You need to create component which is annotated by #Component.
The Component accepts module which provides dependencies.
Every component's name that you create starts with Dagger prefix, e.g. for MyComponent.
Let's look at the following example:
#Singleton
#Component(modules = DemoApplicationModule.class)
public interface ApplicationComponent {
void inject(DemoApplication application);
}
We created ApplicationComponent with single injection method. What we're saying is that we want to inject certain dependencies in DemoApplication.
Moreover, in the #Component annotations we specify module with provision methods.
This is like our module looks like:
#Module
public class DemoApplicationModule {
private final Application application;
public DemoApplicationModule(Application application) {
this.application = application;
}
#Provides #Singleton SomeIntegerHandler provideIntegerHandler() {
return new MySomeIntegerHandlerImpl();
}
}
What we're saying by creating DemoApplicationModule is that the module can provide desired dependencies in the injection place specified by our Component.
public class DemoApplication extends Application {
private ApplicationComponent applicationComponent;
#Inject SomeIntegerHandler handler;
#Override public void onCreate() {
super.onCreate();
applicationComponent = DaggerApplicationComponent.builder()
.demoApplicationModule(new DemoApplicationModule(this))
.build();
applicationComponent.inject(this);
handler.someMethodName(5);
}
}
See documentation what you kind of dependencies you can obtain. Additionally to obtaining just raw instance you can obtain Provider, Factory or Lazy instance.
http://google.github.io/dagger/api/latest/dagger/Component.html
You can also create scoped dependencis, the lifecycles of which depend on the lifecycle of injection places, like Activities or Fragments.
Hope I gave you the basic notion of what Dagger is.

YOU CAN USE SOME INTERFACE
public interface myDependence{
int myFunction(int value);
}
NOW IMPLEMENT IN YOU CLASS
public myClass implements MyDependence{
#Override
int myFunction(int value){
// do something
}
}

What does #Module means in dagger for android?

I have read many blogs but still i am not able to figure out #Module annotation functioning in dagger.
#Inject i got that it provides dependency injection at runtime. But what does #Module does.
since the object graph is also built on module.
For ex i.e i have this snippet of code from https://github.com/AndroidBootstrap/android-bootstrap.
#Module(
complete = false,
injects = {
BootstrapApplication.class,
BootstrapAuthenticatorActivity.class,
MainActivity.class,
BootstrapTimerActivity.class,
}
)
public class BootstrapModule {
}
so what does it basically does. since i am also trying to build one application using dagger as dependency injection for android.But since I am not able to get #Module concept clearly I am just stuck.
Can anyone please help me out with some basic example or concept. I think this will be helpful for all who is using dagger.

If you have a look to the docs for the annotation, a #Module annotated class defines a class that contributes to the dagger object graph. In the Spring framework for example, the equivalent would be the #Configuration anntotation. It defines a configuration point for your object graph, where you declare which objects you want to be available for injection and their scopes.
As a simple example, let's say we want a singleton object to be used by any Activity in the app. It has to be created in the module:
#dagger.Module(injects = {MyActivity.class})
public class Module {
#Provides
#Singleton
public MySinletonBean provideMySingleton() {
return new MySinletonBean();
}
}
This will create a MySingleton object which can be injected in MyActivity. This is a very basic example, but we can perform other actions in the graph there, like using dependencies in the constructors:
#dagger.Module(injects = {MyActivity.class})
public class Module {
private DependencyBean dependency = new DependencyBean();
#Provides
#Singleton
public MySinletonBean provideMySingleton() {
return new MySinletonBean(dependency);
}
#Provides
#Singleton
public MySinletonBean provideMyOtherSingleton() {
return new MyOtherSinletonBean(dependency);
}
}
Then, in MyActivity we need to access the graph for the application in the onCreate method:
#Inject
MySingletonBean singleton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
((MyApplication) getApplication()).getGraph().inject(this);
}
So, who does create the object graph here? The MyApplication class does it when your application starts (don't forger to add it in your androidManifest.xml):
public class MyApplication extends Application {
private ObjectGraph graph;
public ObjectGraph getGraph() {
return graph;
}
#Override
public void onCreate() {
super.onCreate();
graph = ObjectGraph.create(new Module(this));
graph.inject(this);
}
}
So the execution flow in a dagger app would be:
The android app starts and the MyApplication class builds the graph, parsing the #Module annotated classes and keeping an instance of it.
Then, the classes declared in the module can access its objects just injecting themselves in the object graph. Gradle then will evaluate their #Inject annotations and perform the dependency injections.

I guess Annotation Processing Tool requires that to generate code at the compile time.
This makes it Dagger can provide validation at compile time and not only at runtime.