The stock fonts provided with Android aren't bad, but if you need to give your app/game a bit more mood then you need some custom fonts.
To embed a custom font into your app, you need to create an "assets/fonts" folder and copy your TTF file there.
In your code:
Typeface font = Typeface.createFromAsset(this.getContext().getAssets(), "fonts/Jokerman.ttf");
TextView tv = (TextView) v.findViewById(res);