BEIJING — In a move to quell swirling rumors about his health, China’s vice president, Xi Jinping, reappeared in public Saturday after mysteriously vanishing for two weeks, showing no outward signs of injury or illness during a leisurely stroll through a university campus.

While showing that he remains mobile and still in relatively good health, the appearance of Xi — who is slated to become China’s new top leader this fall — left many questions still unanswered.

Xi had not been seen since Sept. 1 and had canceled several appointments with foreign leaders, spawning theories that he had been injured or ill and raising the possibility that his health could jeopardize an upcoming leadership transition.

On Saturday morning, Xi arrived at China Agricultural University in Beijing to attend its celebration of National Popularization of Science Day, according to eyewitnesses and a statement by the state-run Xinhua News Service.

Xinhua also released two accompanying pictures of Xi. In one, Xi is walking outdoors on what appears to be the university’s sunny campus, flanked by other officials who, like him, were wearing dark jackets. Xi’s smile and upright posture in the photo were notable in light of an especially pervasive rumor that he had injured his back.

In recent days, speculation about Xi’s disappearance had ranged from soccer and swimming-related injuries to an attempted assassination by car crash. Most recently, however, party officials had been privately discussing two possibilities: a back injury or a mild heart attack.

This week, one man — who, like Xi, is part of the group of children of revolutionary leaders commonly called China’s ‘‘princelings’’ — said Xi’s mother told a concerned visiting princeling that her son was not feeling well but was recovering from an injury to his lower back. The man spoke on condition of anonymity because of the party’s current crackdown on discussions about Xi.

But one eyewitness at Saturday’s event, who was able to maneuver within a few feet of Xi, said he looked fit. ‘‘He was very talkative and looked very healthy. I think all those rumors about him will be dashed.’’

The man, a student at the agricultural university, spoke anonymously for fear of angering the government. He said Xi’s visit lasted more than 30 minutes and included stops at various booths showing crop and fish farming technology.

According to the student, Xi mentioned to onlookers how China’s main concern in the past was to ‘‘eat full’’ but is now to ‘‘eat well’’ and ‘‘eat healthy.’’ At one point, Xi saw a display on techniques to check melamine levels in milk — a source of some of China’s most serious recent food safety scandals, and he praised the work.