This document discusses managing dependencies injection (DI) with Dagger2. It begins with a quiz on DI concepts. It then covers separating construction from usage, common DI libraries like Dagger1 and Dagger2, annotations used in Dagger like @Module and @Inject, an example pet project using Dagger2, scopes like @Singleton, named dependencies with @Named, and includes links to resources on DI and Dagger2.

1. MANAGE DI WITH DAGGER2
Philips CDPTechTalks #15

2. QUIZ
• ?
• ?
• ?

3. QUIZ
• What is dependencies injection?
• ?
• ?

4. QUIZ
• What is dependencies injection?
• Dependencies injection and dependencies
inversion?
• ?

5. QUIZ
• What is dependencies injection?
• Dependencies injection and dependencies
inversion?
• Who worked with Dagger2?

6. SEPARATE CONSTRUCTION
AND USAGE

7. WRONG
public Car() {
this.motor = new Motor();
}

8. RIGHT
public Car(Motor motor) {
this.motor = motor;
}

9. DI LIBRARIES
• RoboGuice
• Dagger 1 (Classis)
• Dagger 2

10. DI LIBRARIES
• RoboGuice
• Dagger 1 (Classis)
• Dagger 2

11. ANNOTATIONS
• @Module for the classes whose methods provide
dependencies
• @Provides for the methods within @Module classes
• @Inject to request a dependency
• @Component, @Subcomponent are bridge
interfaces between modules and injection

12. EXAMPLE
• A pet project with Dagger 2

13. ANNOTATIONS
• @Module for the classes whose methods provide
dependencies
• @Provides for the methods within @Module classes
• @Inject to request a dependency
• @Component, @Subcomponent are bridge
interfaces between modules and injection

14. SCOPES
• Within scope Dagger will return same instance of
the dependency

15. SCOPES
• @Singlethon
• @Scope

16. @NAMED
@Provides @Named("cached")
OkHttpClient provideOkHttpClient(Cache cache) {
OkHttpClient client = new OkHttpClient();
client.setCache(cache);
return client;
}
@Provides @Named("non_cached")
OkHttpClient provideOkHttpClient() {
return new OkHttpClient();
}

17. @NAMED
@Inject @Named("cached") OkHttpClient
cachedClient;
@Inject @Named("non_cached") OkHttpClient
nonCachedClient;

18. Q&A
• https://lostechies.com/derickbailey/2011/09/22/dependency-injection-is-not-the-same-as-the-dependency-
inversion-principle/
• https://en.wikipedia.org/wiki/Dependency_injection
• http://misko.hevery.com/2008/07/08/how-to-think-about-the-new-operator/
• http://blog.nimbledroid.com/2016/03/07/performance-of-dependency-injection-libraries.html
• http://google.github.io/dagger/
• https://github.com/codepath/android_guides/wiki/Dependency-Injection-with-Dagger-2
• https://www.youtube.com/watch?v=oK_XtfXPkqw
• https://www.youtube.com/watch?v=HAzu57MrGgA
• https://www.youtube.com/watch?v=3B7F7emCc64