[Solved] Setting the position of UIDraggablePanel

[Aki Kanerva]

I am developing a level selection menu that's essentially a long, scrollable list of items using UIDraggablePanel and UIGrid. I'm trying to find a way to initialize the scroll position so that the last played level is visible. However, calling SetDragAmount() on the UIDraggablePanel seems to do weird things: it moves the entire panel as well as the contents.

To test this, open NGUI/Examples/Scenes/Example 7 - Scroll View (Panel).unity, then add the following script to the Click Me button (and disable the UIButton Tween component):

TestDragPanel.cs

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class TestDragPanel : MonoBehaviour {
5.     void Start() {
6.         UIEventListener.Get(this.gameObject).onClick += onButtonClick;
7.     }
8.  
9.     void onButtonClick(GameObject button) {
10.         GameObject gob = GameObject.Find("UIPanel (Clipped View)");
11.         UIDraggablePanel draggablePanel = gob.GetComponent<UIDraggablePanel>();
12.         draggablePanel.SetDragAmount(0.25f, 0f, true);
13.     }
14. }

I would assume that the code would move the scroll position to 25%. And that seems to happen, since in the second picture the scrollbar has moved to the right - but so has the panel itself. See the attachments for screenshots before and after calling the method.

I'm using NGUI 2.3.4 and Unity 4.0.1f2.

Edit: Marked as solved, and clarified subject to match with the solution.

[ArenMook]

To move a panel, you need to adjust its position, then adjust its clipping rect by the inverse of the position.

Look at what I do in SpringPanel -- which, coincidently, is pretty much the script you want to be using in your case anyway.

[Aki Kanerva]

Okay, thanks, that got it working. Bit of a roundabout way of doing it though - I was looking for a shorthand to avoid having to do calculations with the panel's bounds.

Now I'm curious, though. What is SetDragAmount() used for?

[ArenMook]

Callbacks used by scroll bars.

[Aki Kanerva]

Ah, that makes sense. Thanks again for the speedy help!

[taikuukaits]

Hey Aki,

I was wondering if you could share your final solution for saving the scroll position of the UIScrollView. I am trying to do the same thing and automatically scroll it to the last level you selected.

Thanks!

[taikuukaits]

I just realized this is really old and is using UIDraggable instead of UIScrollView. I was looking for UIScrollView so if your code no longer applies, disregard!