Why doesn't work the calling to a method in JAVA (Single example)

Question

I'm working with LeapMotion. I have this code in my main class:

public void onFrame(Controller controller) {
    Frame frame = controller.frame();
    GestoPistola gesto;

    if (!frame.hands().isEmpty()) 
    {
        System.out.println("ENTER");
        gesto.reconocer(frame);
    }
…
}

And then, this is the class GestoPistola, which is the one that has to make all the job.

    public class GestoPistola {
       public enum ESTADO{
           DESCARGADA, CARGADA
       }

       ESTADO _estado;

       public void GestoPistola(){
           _estado = ESTADO.DESCARGADA;
       }

       public void reconocer(Frame f)
       {
           System.out.println("LET'S START");

           if (!f.hands().isEmpty()) {
               System.out.println("Hay mano");
               Hand hand = f.hands().get(0);
               FingerList fingers = hand.fingers();

               switch(_estado)
               {
                     …
               }
           }
        }
   }

So, the consol shows "ENTER", but never "LET'START".

I know it's a really simple question, but I'm not such an expert with JAVA.

Hope someone can help me!

You probably have a Null Pointer Exception in the line `gesto.reconocer(frame);`, correct? — Dherik, Nov 25 '15 at 12:37

score 3 · Accepted Answer · answered Nov 25 '15 at 12:36

3

You never initialize gesto, so you probably get a NullPointerException when you attempt to call reconocer.

Change

GestoPistola gesto;

to

GestoPistola gesto = new GestoPistola ();

answered Nov 25 '15 at 12:36

Eran

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That's it! Thanks a lot! – user3529582 Nov 25 '15 at 12:38

score 2 · Answer 2 · answered Nov 25 '15 at 12:37

2

You never initialize your gesto variable, so there's a NullPointerException.

Change GestoPistola gesto; to GestoPistola gesto = new GestoPistola();

answered Nov 25 '15 at 12:37

Stultuske

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Why doesn't work the calling to a method in JAVA (Single example)

2 Answers2