MainFragment

public class MainFragment extends Fragment {

    private Model mModel;
    private TextView mTextView;


    @Override
    @SuppressWarnings("ConstantConditions")
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mModel = new Model();
        mModel.setFragmentVisible(false);
//        mModel.setName("");
//        mModel.setCount(0);

        mModel.init();

        mModel.subscribe(
                Arrays.asList(Model.FRAGMENT_VISIBLE),
                new Runnable() {
                    @Override
                    public void run() {
                        if (!mModel.isFragmentVisible()) {
                            getActivity().runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    mModel.setCount(mModel.getCount() + 1);
                                }
                            });
                        }
                    }
                });
        mModel.subscribe(
                Arrays.asList(Model.FRAGMENT_VISIBLE),
                new Runnable() {
                    @Override
                    public void run() {
                        if (mModel.isFragmentVisible()) {
                            mModel.setName("" + new Random(System.currentTimeMillis()).nextLong());
                        }
                    }
                });
        mModel.subscribe(
                Arrays.asList(Model.FRAGMENT_VISIBLE, Model.NAME, Model.COUNT),
                new Runnable() {
                    @Override
                    public void run() {
                        if (mModel.isFragmentVisible()) {
                            getActivity().runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    mTextView.setText(mModel.getName() + " " +  mModel.getCount());
                                }
                            });
                        }
                    }
                }
        );
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mTextView = new TextView(getActivity());
        return mTextView;
    }

    @Override
    public void onStart() {
        super.onStart();
        mModel.setFragmentVisible(true);
    }

    @Override
    public void onStop() {
        super.onStop();
        mModel.setFragmentVisible(false);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mModel.deInit();
        // unsubscribe
    }

}

Model

public class Model {

    public static final String FRAGMENT_VISIBLE = "fragment_visible";
    public static final String COUNT = "count";
    public static final String NAME = "name";

    private boolean mIsFragmentVisible;
    private Integer mCount;
    private String mName;
    private ExecutorService mService;
    private Collection<Pair<Collection<String>, Runnable>> mCallbacks;
    private Set<String> mInvokedEvents;

    public Model() {
        mCallbacks = new ArrayList<Pair<Collection<String>, Runnable>>();
        mInvokedEvents = new HashSet<String>();
    }

    public void init() {
        mService = Executors.newSingleThreadExecutor();
    }

    public void deInit() {
        mService.shutdownNow();
    }

    public void fireChange(String field) {
        mInvokedEvents.add(field);
        for (Pair<Collection<String>, Runnable> p: mCallbacks) {
            if (p.first.contains(field) && mInvokedEvents.containsAll(p.first)) {
                mService.submit(p.second);
            }
        }
    }

    public void subscribe(Collection<String> args, Runnable callback) {
        mCallbacks.add(new Pair<Collection<String>, Runnable>(args, callback));
        if (mInvokedEvents.containsAll(args)) {
            mService.submit(callback);
        }
    }

    public boolean isFragmentVisible() {
        return mIsFragmentVisible;
    }

    public void setFragmentVisible(boolean isFragmentVisible) {
        mIsFragmentVisible = isFragmentVisible;
        fireChange(FRAGMENT_VISIBLE);
    }

    public Integer getCount() {
        return mCount;
    }

    public void setCount(Integer count) {
        mCount = count;
        fireChange(COUNT);
    }

    public String getName() {
        return mName;
    }

    public void setName(String name) {
        mName = name;
        fireChange(NAME);
    }

}