Can Anybody give me a code example of Changing font for TextView?

[mili <milimeter 163 com>]

Hi, anybody

  I test the font changing to a TextView, but NO USE! Not only font family is 
not changed, also the font size is the same as before.

  I hope you can give me a successful example, it'd better to select font with 
a GtkFontSelection.

  Thank you.
  mili