+ * A listener interface to learn when the state of a Joystick changes. + *
+ * This API is an optional feature in Nokia UI API, and depending on the device + * capabilities there may be implementations that do not support joystick + * events. The System.getProperty("com.nokia.mid.ui.joystick_event") will + * return "true" if this feature is available in the device. + *
+ * A device may support analogue joystick which detects 360 directions and + * force instead of standard 5 way key navigation. + * (Up, Down, Left, Right and Centre). + *
+ * The joystick sends events every time its position or force changes. + * This events are represented by x (horizontal) and y (vertical) vector + * components. In its original position (centre), the value for (x, y) + * are (0,0). As an example, suppose that the (-5,5) event was received. + * It means that the joystick is held in the left and up diagonal. + * Now, if the (-25,25) event is sent, it means that the Joystick is still + * in the same direction of (-5,5), however more force were applied. + *
+ * The maximum and minimum values of x and y are -127 and 127. + *
+ * If the MIDlet needs to receive joystick events, it must provide + * an implementation of this interface from a Canvas class or subclass thereof. + * The Canvas will still receive standard key / game key events too. + * The Joystick events are sent only if the Canvas is in visible state. + */ +public interface JoystickEventListener +{ + + /** + * Called when the Joystick sends an event. + *
+ * The events are relative to its original position (0,0) + * + * @param x the horizontal component. The value is negative if the + * joystick is moved to the left direction and positive if moved + * to right direction. + * @param y the vertical component. The value is negative if the joystick + * is moved to the down direction and positive if moved + * to up direction. + */ + void joystickEvent(int x, int y); +}