Determine the finger for keytap gesture

[limavolt]

Hi all,

I want to determine which finger do the keytap.
I use this C# to build the code, but the result are not consistent. for example when I tap with thumb, the result was pinky.

here is my code:

case Gesture.GestureType.TYPE_KEY_TAP:
                KeyTapGesture keytap = new KeyTapGesture(gesture);


                    Pointable point = keytap.Pointable;
                    Finger finger = new Finger(point);

                    Finger.FingerType fingerType = finger.Type();

                    SafeWriteLine("Finger: " + finger.Type());

                    switch (fingerType)
                    {
                        case Finger.FingerType.TYPE_THUMB:
                            SafeWriteLine("Thumb");    
                        //do thumb stuff
                            break;
                        case Finger.FingerType.TYPE_INDEX:
                            SafeWriteLine("Index");  
                            //do index stuff 
                            break;
                        case Finger.FingerType.TYPE_PINKY:
                            //do pinky stuff 
                            SafeWriteLine("Pinky");  
                            break;
                        case Finger.FingerType.TYPE_RING:
                            //do pinky stuff 
                            SafeWriteLine("Ring");  
                            break;
                        case Finger.FingerType.TYPE_MIDDLE:
                            //do pinky stuff 
                            SafeWriteLine("Middle");  
                            break;

                    }

                                    break;

I do not know why this can be happen.

Thank you in advance.

[Apidcloud]

Pointable point = keytap.Pointable;
Finger finger = new Finger(point);

It's weird since your code should work just fine. Nevertheless, try to cast the pointable to a finger instead:

Finger finger = keytap.Pointable as Finger;

Sincerely,
Apidcloud

[limavolt]

Thank you @Apidcloud, I have tried to replace the code with your code, but there is an error when running the application, "An unhandled exception of type 'System.NullReferenceException' occurred in consoleLeapCSharp.exe" in the Finger.FingerType fingerType = finger.Type();

[Apidcloud]

That means finger is null for some reason. Try to direct cast it:

(Finger)keytap.Pointable

But the code I mentioned before should work. Pointables can be either Fingers or Tools. Either way, if that also doesn't work, try to check its type first, using is statement.

Sincerely,
Apidcloud

[Joe_Ward]

The code you used to get the Finger object from a Pointable was correct:

Pointable point = keytap.Pointable;
Finger finger = new Finger(point);

Casting doesn't work for these classes (I don't remember why).

As for the original problem, your code works fine.I suspect what you are seeing is that it is easy to tap with two fingers, even when you intend to tap with only one. Open the diagnostic visualizer and turn on the "gesture drawing" feature (press "O"). Compare the keytaps you see in the visualizer to your application printout.

[limavolt]

Thank you @Joe_ward, I have compared with the visualizer. And the results are almost the same. The tap must be not to much, but difficult to do with thumb and pinky finger, do you have suggestion how to do it with thumb and pinky?

[Joe_Ward]

You can change the config parameters to make keytaps easier to perform. This also increases the chance of false-positives. You might try decreasing the minimum speed while increasing the minimum distance. If multiple taps are still a problem, you might need to add your own logic to select the "best" tap (assuming you only want one at a time). For example, you could pick the tap with the highest velocity or the tap with the lowest tap position.