Sources for blog post "Dependency injection with Dagger 2 - Introdution to DI"

LoginActivity.java

public class LoginActivity extends AppCompatActivity {

    LoginActivityPresenter presenter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        OkHttpClient okHttpClient = new OkHttpClient();
        RestAdapter.Builder builder = new RestAdapter.Builder();
        builder.setClient(new OkClient(okHttpClient));
        RestAdapter restAdapter = builder.build();
        ApiService apiService = restAdapter.create(ApiService.class);
        UserManager userManager = UserManager.getInstance(apiService);
        
        UserDataStore userDataStore = UserDataStore.getInstance(
                getSharedPreferences("prefs", MODE_PRIVATE)
        );

        //Presenter is initialized here
        presenter = new LoginActivityPresenter(this, userManager, userDataStore);
    }
}

LoginActivityWithDi.java

public class LoginActivity extends AppCompatActivity {

    @Inject
    LoginActivityPresenter presenter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        //Satisfy all dependencies requested by @Inject annotation
        getDependenciesGraph().inject(this);
    }
}

UserManagerDi.java

class UserManager {

    private ApiService apiService;
    private UserStore userStore;

    //Dependencies are passed as arguments
    public UserManager(ApiService apiService, UserStore userStore) {
        this.apiService = apiService;
        this.userStore = userStore;
    }

    void registerUser() {/*  */}

}

class RegisterActivity extends Activity {

    private UserManager userManager;

    @Override
    protected void onCreate(Bundle b) {
        super.onCreate(b);
        ApiService api = ApiService.getInstance();
        UserStore store = UserStore.getInstance();
        
        this.userManager = new UserManager(api, store);
    }

    public void onRegisterClick(View v) {
        userManager.registerUser();
    }

}

UserManagerNoDi.java

class UserManager {
    
    private ApiService apiService;
    private UserStore userStore;

    //No-args constructor. Dependencies are created inside.
    public UserManager() {
        this.apiService = new ApiSerivce();
        this.userStore = new UserStore();
    }

    void registerUser() {/*  */}

}

class RegisterActivity extends Activity {

    private UserManager userManager;

    @Override
    protected void onCreate(Bundle b) {
        super.onCreate(b);
        this.userManager = new UserManager();
    }

    public void onRegisterClick(View v) {
        userManager.registerUser();
    }
}

UserManagerTests.java

public class UserManagerTests {

    UserManager userManager;

    @Mock
    ApiService apiServiceMock;
    @Mock
    UserStore userStoreMock;

    @Before
    public void setUp() {
        MockitoAnnotations.initMocks(this);
        userManager = new UserManager(apiServiceMock, userStoreMock);
    }

    @After
    public void tearDown() {
    }

    @Test
    public void testSomething() {
        //Test our userManager here - all its dependencies are satisfied
    }
}