Change the position of the Joystick by tap

So I found a solution for this : I worked with Input.touches, get the last touch position, if it's in the restricted area of the joystick, I move the Joystick to that position, in the Began and Stationary phases, and return it to the central position if the phase is Ended.

If anyone is interested, here's the code to that part:

 if (Application.platform == RuntimePlatform.Android)
 {
       Touch[] taps = Input.touches;
        if (taps.Length > 0)
        {
             Touch lastTap = taps[taps.Length - 1];
              if (InRistrictedArea(new Vector3(lastTap.position.x, lastTap.position.y, 0)))
              {
                   if (lastTap.phase == TouchPhase.Began || lastTap.phase == TouchPhase.Stationary)
                         {
                          Vector3 newPos = new Vector3(lastTap.position.x - m_StartPos.x, lastTap.position.y - m_StartPos.y);
                             transform.position = Vector3.ClampMagnitude(newPos, MovementRange) + m_StartPos;
                             UpdateVirtualAxes(transform.position);
                         }
                         if (lastTap.phase == TouchPhase.Ended)
                         {
                             HandleRoll();
                             lastDragTime = Time.time;
                             lastDragPos = transform.position;
 
                             transform.position = m_StartPos;
                             UpdateVirtualAxes(m_StartPos);
                         }
                     }
                 }
 
             }
             else // to test on pc
             {
                 if (Input.GetMouseButtonDown(0))
                 {
                     Vector2 clickPos = Input.mousePosition;
 
                     if (InRistrictedArea(clickPos))
                     {
                         Vector3 newPos = new Vector3( clickPos.x - m_StartPos.x, clickPos.y - m_StartPos.y);
                         transform.position = Vector3.ClampMagnitude(newPos, MovementRange) + m_StartPos;
                         UpdateVirtualAxes(transform.position);
                     }
                 }
                 if (Input.GetMouseButtonUp(0))
                 {
                     HandleRoll();
                     lastDragTime = Time.time;
                     lastDragPos = transform.position;
 
                     transform.position = m_StartPos;
                     UpdateVirtualAxes(m_StartPos);
                 }
             }
         }