sample_of_ViewClickObservable.java

final class ViewClickObservable extends Observable<Object> {
    private final View view;

    ViewClickObservable(View view) {
        this.view = view;
    }

    @Override 
    protected void subscribeActual(Observer<? super Object> observer) {
        Listener listener = new Listener(view);
        
        // Most importantly, pass the observer a Disposable
        observer.onSubscribe(listener);
        
        view.setOnClickListener(listener);
    }

    static final class Listener extends MainThreadDisposable 
                                implements OnClickListener {
        private final View view;

        Listener(View view, Observer<? super Object> observer) {
            this.view = view;
        }

        @Override 
        protected void onDispose() {
            view.setOnClickListener(null);
        }
    }
}