He may change his mind later, but right now Andrew Garfield says the role of comic book superhero Spider-Man in the upcoming reboot of the hit film franchise is a part that could last a lifetime. “I could play this character for the rest of my life,” an enthusiastic Garfield, 27, said at Comic-Con on Friday, where the first few clips of the film were revealed to fans. Comic-Con International, an event where tens of thousands of fans of comics and science-fiction stories gather annually, has become a major launch pad for Hollywood studios promoting movies, and the makers of “The Amazing Spider-Man” delighted them on Friday with a look at its new crime fighter, Garfield. “The Amazing Spider-Man” will land in theaters in 2012, and it has been pitched to fans of Peter Parker — a.k.a. Spider-Man — as a franchise reboot that takes the boy back to his roots as a gawky teenager who acquires the web-spinning capabilities and super strength of a spider. The first three movies, starting with 2002’s “Spider-Man” and directed by Sam Raimi, took in a whopping $2.5 billion worldwide, but the makers decided that to continue thrilling loyal fans, the franchise needed a fresh start.