For the second time in less than a year, Android has suffered a major executive loss.
Barra was an increasingly public face for Android, demonstrating new Android devices such as the July debut of the second Nexus 7 tablet throughout his five years at the company.
A Google spokesperson said that Barra would be missed at the company.
Android co-founder Andy Rubin relinquished leadership of the division in March to longtime Googler and Chrome honcho Sundar Pichai, although Rubin has stayed on at Google. Pichai congratulated Barra on his new job in a Google+ post, while Barra himself wrote that he would be joining the Xioami team in China "in a few weeks" as the vice president of Xioami's global operations.
His new employer is known for its enthusiastic embrace of Android, its charismatic chief executive who has been compared to Steve Jobs, and its skyrocketing value. The company has leapt from being valued to $4 billion at the end of last year to $10 billion earlier this month.
According to All Things D, Barra's resignation is rumored to have occurred before he ended a relationship with a Google employee who is reportedly now dating the company's co-founder, Sergey Brin.
While Xiaomi did not respond to a request for comment before publishing this story, the company did send out a tweet Wednesday evening.
Hugo will be responsible for Xiaomi's international business development and Android strategic partnerships.Welcome and let's do sth big!— Xiaomi (@XiaomiChina) August 29, 2013
Updated at 9:11 p.m. PDT with comments from Pichai and Barra, and at 9:23 p.m. PDT with Xiaomi's tweet.