如何将HandlerThread设置为观察者线程

Question

在下面的代码中，我正在从处理程序线程中调用displayAllMovies（）方法。对于下面的代码中的Single.just，我如何指定观察者线程“将在其上调用onSuccess的线程” 与HandlerThread一样？

代码：

private void displayAllMovies() {
    Log.v(TAG_LOG, "->displayAllMovies is called");
    Single<Boolean> justSingleObservable =  
Single.just(this.isMoviePersistentDatabaseEmpty())
            ...
            ...
            })
            .delay(10, TimeUnit.SECONDS);
            justSingleObservable.subscribeOn(Schedulers.io());
            justSingleObservable.observeOn(Schedulers.io());
            justSingleObservable.subscribe(new SingleObserver<Boolean>() {
        @Override
        public void onSubscribe(Disposable disposable) {
            Log.v(TAG_LOG + "->" + "SingleObservable", "onSubscribe");
            Log.d(TAG_LOG + "->" + "SingleObservable", " disposable: " + 
 disposable);
            Log.d(TAG_LOG + "->" + "SingleObservable", " 
 disposable.isDispose: " + disposable.isDisposed());
        }
        @Override
        public void onSuccess(Boolean aBoolean) {
            Log.v(TAG_LOG + "->" + "SingleObservable", " onSuccess");
            Log.d(TAG_LOG + "->" + "SingleObservable", " bBoolean: " + 
 aBoolean);
        }
        @Override
        public void onError(Throwable e) {
            Log.v(TAG_LOG + "->" + "SingleObservable", " onError");
            Log.d(TAG_LOG + "->" + "SingleObservable", " e.getMessage: " + 
 e.getMessage());
        }
    });
 }