<Button
  android:id="@+id/button2"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:textColor="#ff0000"
  android:text="@string/icon_heart" />

<!-- This is the Java Code
  Typeface font = Typeface.createFromAsset( activity.getAssets(), "fontawesome-webfont.ttf" );
  ...
  button.setTypeface(font);
-->