code: public static SpannableString typeface(CharSequence sequence, TypefaceCollection typefaceCollection, int style) {
  		checkTypefaceStyleThrowing(style);
  		SpannableString s = new SpannableString(sequence);
  		s.setSpan(new TypefaceSpan(typefaceCollection.getTypeface(style)), 0, s.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
  		return s;
  	}
docs: Return spannable string with applied typeface in certain style
  see: http://stackoverflow.com/questions/8607707/how-to-set-a-custom-font-in-the-actionbar-title
  
  @param sequence    content
  @param typefaceCollection Collection of typefaces
  @param style     Typeface.NORMAL, Typeface.BOLD, Typeface.ITALIC or Typeface.BOLD_ITALIC
  @throws IllegalArgumentException when invalid style is passed
  @return SpannableString that can be used in TextView.setText() method