Android Express Events Library

new UIEvent("button.ok.click").post(view); // yes, this is it

public class CustomFragment extends Fragment implements UIEventListener {
//  .....
    @Override
    public boolean onMessage(@NonNull UIEvent uiEvent) {
        switch (uiEvent.what) {
            case "button.ok.click":
                Log.d(uiEvent.toString());
                return true; // to stop message propagation
        }
        return false;   // to let other objects to process message
    }
}

new UIEvent(12345).send(viewGroup);

new UIEvent(12345)
    .setText("some text to pass with message")
    .setNumber(9876) // some integer to pass with message
    .putAll(bundle)
    .post(viewGroup);

public class FragmentReceiver extends FrameLayout implements UIEventListener {
//  .....
    @Override
    public boolean onMessage(@NonNull UIEvent uiEvent) {
        switch (uiEvent.code) {
            case 12345:
                Log.d("FragmentReceiver", "text="+uiEvent.getText());
                Log.d("FragmentReceiver", "number="+uiEvent.getNumber());
                return true; // to stop message propagation
        }
        return false;   // to let other components to process the message
    }
}

new UIEvent(12345, "button.ok.click"))
    .post(view);

public class FragmentReceiver extends Activity implements UIEventListener {
//  .....
    @Override
    public boolean onMessage(@NonNull UIEvent uiEvent) {
        switch (uiEvent.code) {
            case 12345:
                if(uiEvent.what.equals("button.ok.click")){
                    // ...
                    return true; // to stop message propagation
                }
        }
        return false;   // to let other components to process the message
    }
}

new UIEvent("button.ok.click")
    .setNamespace("lib_name.company_name.com")
    .post(view);

public class FragmentReceiver extends Fragment implements UIEventListener {
//  .....
    @Override
    public boolean onMessage(@NonNull UIEvent uiEvent) {
        // return false if this is not library message
        if (!uiEvent.getNamespace().equals("libname.company.com")) return false;

        switch (uiEvent.what){
            case "button.ok.click":
                Log.d(uiEvent.getText());
                return true; // to stop message propagation
        }
        return false;   // to let other objects to process message
    }
}