The White House has had an iPhone app for a while now. In fact, it’s inching toward a half million downloads. Now, the administration is branching out into the Android world. Both apps allow users to access audio, video, written briefings, White House blogs, and get alerts. The White House says almost 7 percent of the visitors to the whitehouse.gov website already come from either iPhone or Android devices. And their figures show the traffic from those mobile platforms to the president’s official site has nearly doubled in the past year.