Dagger2 in 3 minutes

Dagger2InThreeMinutes.java

//SHALL WE BEGIN?

//FILE 1 - THE MODULE

@Module //MODULE IS WHAT YOU WANT TO INSTANTIATE.
public class UserLoginModule {

    @Provides //@PROVIDES RELEASE THE OBJECT TO INJECTION.
    @PerActivity //@PERACTIVITY IS THE SCOPE, LIKE BOUNDS WHERE YOU CAN USE THAT.
    public UserModel getUser(){
        return new UserModel();
    }
}

//FILE 2 - THE COMPONENT

@PerActivity
@Component(modules = {UserLoginModule.class}) 
public interface MainComponent {
    
    //COMPONENT IS WHERE YOU WANT INSTANTIATE THE @PROVIDES METHODS OF THE MODULE.
    void injectIntoMainActivity(MainActivity mainActivity);
    
   //GradeResponse injectIntoGradeResponse(GradeResponse gradeResponse); --> this you
   //can use to inject into classes that aren't activities.

    
}

//FILE 3 - THE MYAPPLICATION

public class MyApplication extends Application {
//"MYAPPLICATION" IS A RELEASE OF THE DAGGER2 INSTANCE AND COMPONENTS TO ALL CLASSES.

    private static MainComponent mainComponent;

    @Override
    public void onCreate() {
        super.onCreate();
        initDagger();
    }

    private void initDagger() {
        mainComponent = DaggerMainComponent
                .builder()
                .userModule(new UserModule())
                .build();

    }

    public static MainComponent getMainComponent() {
        return mainComponent;
    }

}

//FILE 4 - THE MAIN/ANOTHER CLASS

//INSIDE ONCREATE PUT THIS:

 MyApplication.getMainComponent().injectIntoMainActivity(this);

//OR INSIDE A METHOD OF ANOTHER CLASS THAT IS NOT AN ACTIVITY:

 MyApplication.getMainComponent().injectIntoAnotherClass(this);

//STILL ON FILE 4, ON GLOBAL SCOPE OF THE CLASS:

@Inject //@INJECT IS THE OBJECT THAT YOU WANT TAKE FROM MODULE.
UserModel userModel;

//FILE 5 - SCOPE

@Scope
@Retention(RetentionPolicy.CLASS)
public @interface PerInstance {}

//Dont forget inside the manifest:

<Application
android:allowBackup="true"
android:name="MyApplication">

//NOW LET'S PUT A SMILE ON THAT FACE - YOU LEARNED FUCKING DAGGER2 IN LESS THAN FIVE MINUTES.