Guilherme-HRamos

@FunctionalInterface
public interface Logger {
    void logMessage(String message);
}

Guilherme-HRamos

public class OpenFileHelper {

    private final Logger myLogger;

    public OpenFileHelper() {
        // logs strategies
        SystemsLogger systemsLogger = new SystemsLoggerImpl();
        LogCatLogger logCatLogger = new LogCatLoggerImpl("OpenFileHelper");

        // log manager

Guilherme-HRamos

public class LoggerDispatcher implements Logger {

    private final List<Logger> loggerList = new ArrayList<>();

    public LoggerDispatcher(Logger... loggers) {
        Collections.addAll(loggerList, loggers);
    }

    @Override
    public void logMessage(String message) {

Guilherme-HRamos

public interface LogCatLogger extends Logger {
}

Guilherme-HRamos

public interface Presenter {
  
    void onUpdateAccount(String newName, String newEmail);
  
    void onRemoveAccount();
    
}

Guilherme-HRamos

public class MainActivity extends AppCompatActivity implements ViewContract {

    private AccountManagerPresenter presenter;

    private Button updateAccountButton;
    private Button removeAccountButton;
    private EditText nameInput;
    private EditText emailInput;

    @Override

Guilherme-HRamos

public class AccountManagerPresenterImpl implements AccountManagerPresenter {

    private final ViewContract viewContract;

    public MainPresenter(ViewContract viewContract) {
        this.viewContract = viewContract;
    }

    @Override
    public void onUpdateAccount(String newName, String newEmail) {

Guilherme-HRamos

public class ButtonConfigHelper implements View.OnClickListener {

    // Exemplo do Listener como classe anônima
    private void setupClick(Button button) {
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                logMessage("setupClick() called");
            }
        });

Guilherme-HRamos

public class OpenLogFileActivity extends AppCompatActivity {

    // some Activity code here

    private void onOpenLogButtonClick() {
        // Usando uma classe anônima como Callback
        new OpenFileHelper("home/log.txt", new OpenFileHelperCallback() {
            @Override
            public void onFileOpenSuccess(File file) {
                // do something with file

Guilherme-HRamos

// Interface usada na herança
interface ParentInterface {
    void firstMethod();
    void secondMethod();
}

// Interface derivada de ParentInterface
interface ChildInterface extends ParentInterface {
    // Herança
    // 1.Não é necessário sobrescrever os métodos herdados de