The pilot reported that during taxi after landing on a 2,550-ft-long asphalt runway, he intended to retract the flaps, but accidently retracted the landing gear, resulting in the nose gear and right main landing gear collapsing on the runway. The pilot added that that there were no preimpact mechanical malfunctions with the airplane. Examination of the accident site revealed runway scrape marks and propeller strikes originating about 1,000 ft beyond the approach end of the runway. The marks extended about 500 ft and terminated at the wreckage, off the left side of the runway. The left main landing gear remained extended and the right wing and lower fuselage sustained damage. The length of scrape marks and extent of damage were consistent with a landing gear collapse during a high-speed landing rollout, rather than a low-speed taxi after landing. The airplane was equipped with a squat switch on both main landing gear to prevent inadvertent landing gear retraction on the ground; however, the switch required weight-on-wheels to work effectively. It's likely that the pilot bounced the landing and attempted to retract the flaps in an effort to settle the airplane on the runway for better wheel braking; however, without weight on the right main landing gear, the gear retracted when the pilot inadvertently moved the landing gear lever instead of the flap lever.