Dagger 2.0 - new dependency injection for Android (Droidcon Krakow 2014)

Short introduction to Dagger 2.0 during Droidcon Kraków 2014.

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1. Dagger 2.0 New dependency injection for Android Radosław Piekarz
2. Spring • Popular in the Java community • Polularized DI/IoC • XML configuration
3. Guice / RoboGuice • Used new features in Java 1.5 • No XML configuration • Not so easy to debug • Runtime validation
6. Dagger 1 • Compile time validation • Do more work during compile and less in runtime • Faster than Guice/RoboGuice
7. Dagger 1 • Not proguard safe • Runtime graph composition
8. Source: Jake Wharton
9. Minimal graph creation time - not just fast, but hand-written DI fast
10. Full, static inspection of code paths
11. No reflection, no explicit classloading
12. Dagger 2 API • @Module & @Provides - mechanism for providing dependencies • @Inject - mechanism for requesting dependencies • @Component bridge between modules and injections
13. Example module @Module class PumpModule { @Provides Pump providePump(Thermosiphon pump) { return pump; } }
14. @Inject class CoffeeMaker { private final Lazy<Heater> heater; private final Pump pump; @Inject CoffeeMaker(Lazy<Heater> heater, Pump pump) { this.heater = heater; this.pump = pump; }
15. @Component @Component(modules = {DripCoffeeModule.class}) public interface Coffee { CoffeeMaker maker(); }
16. Example app public class CoffeeApp { public static void main(String[] args) { Coffee coffee = Dagger_Coffee.builder() .build(); coffee.maker().brew(); } }
17. Dagger 1 vs Dagger 2 public class CoffeeApp implements Runnable { @Inject CoffeeMaker coffeeMaker; @Override public void run() { coffeeMaker.brew(); } public static void main(String[] args) { ObjectGraph objectGraph = ObjectGraph.create(new DripCoffeeModule()); CoffeeApp coffeeApp = objectGraph.get(CoffeeApp.class); coffeeApp.run(); } }
19. Quick demos
20. u2020 & u2021 https://github.com/Jak eWharton/u2020 https://github.com/cgr uber/u2020/tree/dagg er2
21. Dagger 2 Pros • It is really fast • Compile time validation for entire graph • Easy debugging Cons • Not flexible • There is no dynamism
22. https://github.com/google/dagger/ https://google.github.io/dagger/
23. Q&A Thank you for your attention! radzio RadoslawPiekarz { }