Android: Get Direction from touch

Hi,

I am trying to make a game like "PaperToss".

For the moment i can launch a ball in a trash, but only if i touch it.

 public int angle = 50;
 public int speed = 100;
 public int dir = 0;
 
 ball.rigidoby.AddRelativeForce(new Vector3(dir, angle, speed));

But i want to get the direction from the user fingers.

Somebody can help me on how to do that ?

Thanks.