From the L.A. Times:
"...He composed music for about 3,000 TV series episodes, pilots and TV movies -- as well as composing the themes for popular shows, including "That Girl," "Gomer Pyle, U.S.M.C.," "The Mod Squad" and "Mickey Spillane's Mike Hammer."
Hagen also composed the themes for “The Andy Griffith Show,” "The Dick Van Dyke Show," and "I Spy", among others.
According to the Times story, Hagen is the person doing the whistling on the Griffith theme.
http://www.latimes.com/news/obituaries/la-me-hagen28-2008may28,0,1985685.story
"...He composed music for about 3,000 TV series episodes, pilots and TV movies -- as well as composing the themes for popular shows, including "That Girl," "Gomer Pyle, U.S.M.C.," "The Mod Squad" and "Mickey Spillane's Mike Hammer."
Hagen also composed the themes for “The Andy Griffith Show,” "The Dick Van Dyke Show," and "I Spy", among others.
According to the Times story, Hagen is the person doing the whistling on the Griffith theme.
http://www.latimes.com/news/obituaries/la-me-hagen28-2008may28,0,1985685.story