Problem with instantiate UI prefabs

When I instantiate prefab with RectTransform on it in most cases it works wrong. Usually ancoredPosition and deltaSize resets and I have to set it again from script. There are another bug that I think linked to the same. I use ReferenceResolution that in all phones interface scale and looks well. And it works well with UI elements that allready exist on scene, but when I instantiate prefab with RectTransform its not scale at all. This bug has always is reproduce (((

 

Are you making sure to set the instance's parent to the Canvas (or a Canvas element) using transform.SetParent(parent, false)?

 

I also struggled with that instantiation issue. It's not so much 'right' or 'wrong', it's just what the system does. When you use the simple version of Instantiate, the one without the position or rotation argument, then the new object just shows up at some semi-random place. I believe this is what is supposed to happen.

To instantiate an object at a specific position / rotation, you have two options:

1) Do what you've been doing, use the simple version of Instantiate, and then use anchoredPosition and localPosition to relocate the new object.

2) Use the longer call to Instantiate, the one that has both a position and a rotation argument. For example, if you want the new object to have the same position and rotation as the prefab, you do this:

Code (CSharp):

1.  
2. newobject = Instantiate (prefabobject, prefabobject.transform.position, prefabobject.transform.rotation) as GameObject;
3.  

 

I do this:
LeaderboardSlot leaderboardSlot = Instantiate(leaderboardSlotPrefab) as LeaderboardSlot;
leaderboardSlot.transform.parent = leaderbordGrid;

 

The problem isn't in "what place the object appears". Example: I have prefab, It's Image this 10,10,0 position. It have children Text this 50,0,0 local position. When I instantiate prefab Text now have 0,0,0 local position.
Another part of the problem is that the object appears in the wrong scale (it is smaller / bigger than it should be). Its scale should establish ReferenceResolution, but he don't for some reason

 

Have this problem too.. I didnt see any information on how to instantiate correctly the new UI... only how to position them staticly before the game starts..

If i have a canvas and i want to instantiate any ui to it, and the resolution doesnt stay the same as when I created the prefab of the UI, it will be positioned wrong when I instantiate it in the new resolution...
Also, when using ReferenceResolution the instantiated UI wont have the right size as it should have if the UI wouldnt be instantiated (but will be there staticly)

 

Great news and many thanks to Senshi!

I have tried using "transform.SetParent(anotherTransform, false)" instead of "transform.parent = anotherTransform" and it works perfectly now!

 

Hit this same issue and just to chime in...

Doesn't scale prefab to UI scale:
go.transform.parent = this.rows.transform;

Doesn't scale prefab to UI scale:
go.transform.SetParent(this.rows.transform);

DOES scale prefab to UI scale :
go.transform.SetParent(this.rows.transform, false);

 

With me is even weirder, the instances appears in the editor but they are no visible, as the would appear if they were not child of canvas, what isn't the case! any idea what is going on here?

 

Thanks so much for that! Was searching around for a bit, almost 0 info of how to solve these things. The 3rd option worked for me

 

This fixed my problem too. I couldn't understand why there were such huge gaps between the items in a vertical Iayout group. I spent several hours researching this. The breakthrough came after creating manually instances of my prefab before letting the code do it and then comparing the inspector output. Now instead of googling for big gaps I was googling for wrongly sized prefab instantiations and so stumbled over this page. Thank you, Senshi, you saved me yet more hours of pain.

 

That did it for me. Thanks!

 

Had to chime in on my personal problem and fix. I had a problem with the Instantiated UI Button being way too big. It does NOT follow the scale of it's parent. My background panel was at 0.73 scale and the instantiated button was at 1.0. Don't scale your UI's, readjust their widths and heights.

 

So I'm always makin simple mistakes... here's what I finally realized when none of these worked..... my prefab texts were children of another canvas in my project folder.... when it was reading the transform for instantiation, it was pickin up the 0,0,0 even though I had put texts all over the place...(that's what I'm guessin...) Since I had my stuff right where I wanted it (and de-parenting messed up the positions, and readjusting those was gonna take a while) I instantiated at the prefab's transform.localPosition instead of position and they all came out great...

 

Thanks for posting this! The last variant both solved a similar problem I was having and gave me deeper insight into how Unity works. The reason that it works and the explanation to why I keep running into strange scaling and positioning issues when instantiating prefabs is in the docs:

 

Thumbs up Senshi, that did it for me! I was putting true, but I needed false.

transform.SetParent(parent, false)

 

Thanks Senshi!
i scratched my head for a while with this issue. It does make sense, but first i didn't think the issue was in the parenting, i thought it was in some canvas component paramenter.

 

Thank you Senshi!
Passing the second parameter as false solved a similar problem I had! Now the children I instantiate a run-time scale with the parent that is added in the editor.

 

Thank you, that helped!

 

I was using SetParent, just not the false setting ... sigh. Fixed everything. Thanks!

 

My HERO! I've been pulling my hair out for days following the Shop UI tutorial using their exact code and my buttons being blown out massively. And having false in the set parent fixed it so thanks so much!

 

THANKS BRO

 

THANKS this solved my problem.

 

Brilliant! This has put an end to days of debugging!!!

 

Thanks Senshi, frustration is over!

 

You are a god. Thank you!

 

I had to re-set it's position e.g.

Code (csharp):

1.  
2.             GameObject g = (GameObject)Instantiate(gameObject, transform.position, Quaternion.identity);
3.             g.transform.SetParent(transform.parent, false);
4.             g.transform.position = transform.position;
5.  

 

I've been banging my head against this for a while, too with slightly different circumstances. I have a scroll list which populates with profile names from a list of names that can be any length. I was getting all kinds of crazy sizes for my buttons, depending on the resolution at the time. The buttons were also very clearly stretched and the text, when it was the right size, was pixelated and blurry.

The code I wound up with which worked was

Code (CSharp):

1. GameObject spawnedGameObject = (GameObject)GameObject.Instantiate(panelPrefab);
2.             spawnedGameObject.transform.SetParent(contentPanel);
3.             spawnedGameObject.transform.localScale = new Vector3(1, 1, 1);

The key here was the last line to set the local scale. Once that was applied, the prefabs scaled up and filled up the space properly.

 

Below has been the most reliable way for me to position and stretch

Code (CSharp):

1.             _uiInvPanel.transform.SetParent(_playerInventoryHolder.transform);
2.             _uiInvPanel.RectTransform.sizeDelta = _playerInventoryHolder.rect.size;
3.             _uiInvPanel.RectTransform.anchoredPosition = _playerInventoryHolder.anchoredPosition;

 

I had the same in my UI scroll list. Instantiating a prefab game object - with SetParent and it's parameter: worldPositionStays set to false - was working fine.

However when I returned it to the object pool and activate it again from the pool... the damn thing shrank every time more and more. Making sure to set the transform localScale to 1 to prevent scaling madness.

Code (CSharp):

1. GameObject menuItem = _menuItemPool.GetObject();
2. menuItem.transform.SetParent(GetComponent<Transform>(), false);
3. menuItem.transform.localScale = new Vector3(1, 1, 1);

 

Workaround retains the prefab values only after activating it through code if it's instantiated inactive.

Algorithm:

1) Instantiate the prefab inactive
2) Set the object active.

Code:

public class SomeClass: MonoBehaviour {

public GameObject Prefab;

RetainPrefabParms()
{
Prefab.SetActive(false);
GameObject buttonMask = Instantiate(Prefab);
buttonMask.transform.SetParent(this.transform,false);
buttonMask.SetActive(true);
}

 

Thanks a lot for this. This is what i had to do. Im trying to add health bar on game objects on run time. I made a prefab and everything for the Health bar. But it wasn't appearing over the gameobject. I did this and the health bars were shown above the game objects.

 

This worked perfectly, thanks!

 

Thank you. This has been stressing me for a while

 

It works for me, thanks!
I used
[gameObject.transform.parent = mother.transform; ] : It doesn't work
and [gameObject.transform.SetParent(mother.transform,false); ] : It works!

 

man I didnt know that, saved my day thanks!!

 

All the way into 2022 you are still saving devs. Bless you.

My specific issue had to do with instantiating UI elements at runtime for a dynamic menu.