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Respond to a user sliding a finger up quickly on the screen

  1. Import the following classes:
    • net.rim.device.api.ui.TouchEvent
    • net.rim.device.api.ui.TouchGesture
    • net.rim.device.api.ui.Field
    • net.rim.device.api.ui.Manager
    • net.rim.device.api.ui.Screen
    • net.rim.device.api.ui.component.Dialog
  2. Create a class that extends the Manager class, the Screen class, the Field class, or one of the Field subclasses. 
    public class newButtonField extends ButtonField {
  3. In your implementation of the touchEvent(TouchEvent message) method, invoke TouchEvent.getEvent().
  4. Check if the value that TouchGesture.getSwipeDirection() returns is equal to TouchGesture.SWIPE_NORTH. 
    protected boolean touchEvent(TouchEvent message) {
   switch(message.getEvent()) {
      case TouchEvent.GESTURE:
         TouchGesture gesture = message.getGesture();
         switch(gesture.getEvent()) {
            case TouchGesture.SWIPE:
               if(gesture.getSwipeDirection() == TouchGesture.SWIPE_NORTH) {
                  Dialog.alert("Upward swipe occurred");
                  return true;
               }
         }
         return false;
   }  
}
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