For the second year in a row, the iHeartRadio Awards became the iHeartTaylorSwift show.
Swift, who swept the awards last year, won the first and last prize Sunday night — female artist and album of the year. In between, she claimed best tour honors for her star-studded "1989 World Tour," thanking boyfriend Calvin Harris (real name: Adam Wiles) from the stage.
"For the first time, I had the most amazing person to come home to when the spotlight went out and when the crowds were all gone," Swift said. "So I want to thank my boyfriend Adam for that."
Harris won dance artist of the year. Gomez took the "biggest triple threat" award.
Bono and the Edge from U2 accepted the show's Innovator Award, presented by last year's winner, Pharrell Williams.
"The thing that might be the most innovative about our band is we are a real band," Edge said. "We are still in our high school band."
Song of the year went to Adele for "Hello." She accepted via video from a performance in Birmingham, England. Other winners at the fan-voted show included Fetty Wap (best new artist), Pitbull (Latin artist of the year), and Chris Brown (R&B artist of the year). All three men also performed during the show.
Brown thanked "everybody who supported me through all the worst times in my life and the positive times in my life."
"I tend to not have a filter sometimes, and I go off on a lot of people," said Brown, who has been dogged by legal troubles since pleading guilty to felony charges in 2009 for beating then-girlfriend Rihanna. "But the music stays the same."
There were as many performances as awards presented during the three-hour show, hosted by Jason Derulo and broadcast live on TNT and TBS from the Forum in Inglewood, California.
Justin Bieber was the first to perform, showing off his new dreadlocks during a mash-up of "Love Yourself" and "Company." He returned to the stage twice as a winner, claiming male artist of the year and sharing in the dance song of the year award with Diplo and Skrillex for "Where Are U Now."
Bieber thanked his fans for standing by him through what he described as "tough times."
"It's just about our growth and learning," he said.
Meghan Trainor performed her new single, "No."
Demi Lovato also took the stage and she was joined by an unlikely accompanist: Brad Paisley, reported People Magazine.
The country star, 43, backed Lovato, 23, on guitar as she sang "Stone Cold," the latest single off her smash album Confident.
Iggy Azalea unveiled her new song, "Team," during the ceremony, while Zayn Malik made his solo awards show performance debut, performing "Like I Would" from his new album, "Mind of Mine."
Other performers included DNCE, The Weeknd, show host Jason Derulo, and Maroon 5, which was named duo or group of the year.