Instantiating many UI elements is incredibly slow

I want to instantiate many items to be placed in a ScrollRect. Each item is a button, has six Panel children, and each of those has a Text child. It's basically a list of people's attributes (Name, Gender, Age, etc). I have a prefab of this item that, within a for loop, I want to instantiate many times as a RectTransform and attach to the ScrollRect's content.

However, this gets to be very slow. I try to instantiate 100 list items and the game freezes for a couple seconds while it works. This doesn't even include parenting the item to the content panel or finding the item's children to modify text values.

Is there a different way I should be going about this?

 

You'd probably have to profile it to figure out which functions are actually taking up the bulk of the time to figure out what's going on. There are way too many moving parts to just sift through logically.

 

There's no extra logic to it, it's simply instantiating these UI elements. The problem is there are just too many objects I guess. And at some point Unity reaches it's vertex limit. I can sort of circumvent these problems by populating the scrollview in a coroutine, and disabling components of list items outside the viewport, but eventually it will get to be too much and the FPS will drop dramatically.

Is there another method to create large detailed lists in Unity?

 

Ditto, I'm in the same. A grid with multiple buttons- 100-200. Coroutine is one option for splitting into frames.

Have you tested your grid on low-end android devices? It appears that dynamic grid/scroll-rect item creation does not work on low-end devices.

 

Instantiating is "slow" for all objects. By your accounts it seems to be even slower for UI elements, which makes sense as there are probably more things going on behind the scenes than for a simple mesh.

The best way to handle situations when you know you will be instantiating a lot of items is to instantiate a pool of them ahead of time when a pause is not as noticeable, or to create the pool over a second or two.

 

I haven't tested it on Android, but it's slow on my relatively powerful machine so I imagine it won't fare much better on a phone. It does seem like this isn't an easily solvable issue in Unity, especially if you list changes constantly through filters and sorting, as I would like mine to do.

For now I've put a hard cap on the number of items in my lists, though it's a shame that the knowledge of that cap will dominate my design process as I continue.

One idea I haven't yet tried is to set the size of the ScrollRect's content manually (so that the scrollbar is correct), and only instantiate list items that would be present given the scrollbar's current value... but I haven't worked out the specifics, or whether that would even be a better method.

 

Hi. We've ran into the same issue and developed our own utility that greatly increases performance.
It's 5 bucks on asset store(see the video for comparisons): https://www.assetstore.unity3d.com/en/#!/content/58158

EDIT 27.08.2016: happy to announce V2.0 is out, improved and with horizontal scrolling support: http://u3d.as/xXQ