Pro Android 4

Multitouch

Now that you’ve seen single touches in action, let’s move on to multitouch. Multitouch has gained a lot of interest ever since the TED conference in 2006 at which Jeff Han demonstrated a multitouch surface for a computer user interface. Using multiple fingers on a screen opens up a lot of possibilities for manipulating what’s on the screen. For example, putting two fingers on an image and moving them apart could zoom in on the image. By placing multiple fingers on an image and turning clockwise, you could rotate the image on the screen. These are standard touch operations in Google Maps, for instance.

Android introduced support for multitouch with Android SDK 2.0. In that release you were able to (technically) use up to three fingers ...