Interacting with touch events

The most emblematic innovation of today's smart phones is the touchscreen, which has replaced the now antique mice. A touchscreen detects, as its name suggests, touches made with fingers or styluses on a device's surface. Depending on the quality of the screen, several touches (also referred to as cursors in Android) can be handled, de-multiplying interaction possibilities.

So let's start this chapter by handling touch events in DroidBlaster. To keep the example simple, we will only handle a single "touch". The goal is to move the ship in the direction of touch. The farther the touch, the faster the ship goes. Beyond a predefined range TOUCH_MAX_RANGE, the ship's speed reaches its speed limit, as shown in the following figure:

Note

The resulting project is provided with this book under the name DroidBlaster_Part13.