Change the "reference position" of an elastic scroll rect

Questions & Answers
1

Hello,

I meet a problem with a Unity ScrollRect :

  • I have a looooong item list hidden with a Mask. At the beginning, the local position of the ScrollRect content (my item bar) is Pos X=0.
  • If the user scroll to left to see the hidden items, the movement is Unrestricted
  • If the user scroll to right before the first item (where there is nothing to see), the movement switch to Elastic then the bar reset its position to 0 with a nice elastic movement.

The problem comes on the other side, when the user scroll to left after the last item (where there is nothing to see). The movement switch to Elastic, but I would like the bar to reset its position not to 0, but to the maximum allowed position I set to turn the movement to Elastic (so not reset to the first item but stay on the last item).

I can’t find a simple way to do this. The documentation says :

“Use Elastic or Clamped to force the content to remain within the bounds of the Scroll Rect”

But I am not sure about what it’s mean and if there is a simple way to control this.
How should I deal with this ?

2

Ok, I didn’t find any simple solution to this porblem. By “simple” I mean something that you do easily with the editor and a few lines of code.

So this is the approach I eventually use :

  • No switch to the “Elastic” movement

  • A custom code to make the elastic effect on each side, using a slerp function

     /**
  * Let's say that as long as you are touching the screen, you can scroll 
  * (just slow down the speed when you are out of bounds).
  * This piece of code show what happen when the screen is not touched
  * and we are out of bounds on one of the side.
  */ 
 float vSpeed = 10.0f;
 if (vPosX > _maxPosScrollable)  // Out of bounds
 {
 	if( vPosX -_maxPosScrollable <= 0.05 ) // consider the movement finished
 	{
 		_scrollableRect.localPosition = new Vector3 (0.1f, 0f, 0f);
 		_scrollRect.velocity = Vector2.zero; // stop the scroll
 	}
 	else // the elastic effect
 	{
 		vSlerp = Vector3.Slerp(vX, vTarget, Time.deltaTime * vSpeed);
 		vPosX = vSlerp.x; // set the current position of the bar with a slerp between the previous position and the wanted position
 	}
 }

Something like this, adapted to your own case (I guess there is a way to do something cleaner but I didn’t have more time to spend on this).

If someone need this one day, I can give more precisions.