android - How to specify font style in TextView

I want to implement different font in different TextViews.

I am trying to implement fonts from assets with this.

tf = Typeface.createFromAsset(v.getContext().getAssets(), "Roboto.ttf");
bellow_name.setTypeface(tf);

But I have TextView something like this

((TextView) findViewById(R.id.news_date)).setText(news.news_date);

How can I implement Typeface with above TextView?