Changing a (new) UI Image's alpha value

Hi, I am new to Unity.

I have 3 images on my UI that are set at 0.5 alpha. When the player collects a collectable in the game, I would like one of the images to turn to full alpha, then the same for collectable 2 and so on...

I'm sure it's a easy process, but I just can't seem to work it out.

Help would be very much appreciated.

Thanks.

 

Be sure to check the documentation before asking here! You'll get your answers much quicker

That being said:

Code (CSharp):

1. using UnityEngine.UI;
2.  
3. public class Example : MonoBehaviour {
4.     Image image;
5.  
6.     void Start() {
7.         image = GetComponent<Image>();
8.         image.color = Color.white; //or whatever color
9.     }
10.  
11. }

 

Wouldn't it be better to actually set the alpha, instead of changing color?

Code (CSharp):

1. using UnityEngine.UI;
2. public class Example : MonoBehaviour {
3.     Image image;
4.     void Start() {
5.         image = GetComponent<Image>();
6.  
7.         Color c = image.color;
8.         c.a = 0;
9.         image.color = c;
10.     }
11. }

 

Thanks for the replies. PGJ, yours was exactly what I wanted, cheers!

 

You can create an extension, so that you can use anywhere on your code:

Code (CSharp):

1. public static class Extensions
2. {
3.     public static void SetTransparency(this UnityEngine.UI.Image p_image, float p_transparency)
4.     {
5.         if (p_image != null)
6.         {
7.             UnityEngine.Color __alpha = p_image.color;
8.             __alpha.a = p_transparency;
9.             p_image.color = __alpha;
10.         }
11.     }
12. }

Then you can just call this from anywhere:

Code (CSharp):

1. button.GetComponent<Image>().SetTransparency(float value);

 

What version of unity is this?

 

Why doesn't this work for setting the alpha? My health bars are constantly 255 alpha. They do change to the correct colors though.

Code (CSharp):

1.   private void UpdateHpImage()
2.   {
3.     var percentHP = (float)Data.CurrentHP / Data.MaxHP;
4.     hpImage.fillAmount = percentHP;
5.     if(percentHP == 1)
6.     {
7.       hpImage.gameObject.SetActive(false);
8.     }
9.     else
10.     {
11.       hpImage.gameObject.SetActive(true);
12.     }
13.     if(percentHP > .5f)
14.     {
15.       hpImage.color = new Color(0, 255, 0, 45);
16.     }
17.     else if(percentHP <= .5f && percentHP > .25f)
18.     {
19.       hpImage.color = new Color(255, 255, 0, 45);
20.     }
21.     else if(percentHP <= .25f)
22.     {
23.       hpImage.color = new Color(255, 0, 0, 45);
24.     }
25.   }

 

I guess The a in color for some reason is a float between 0 and 1 for transparency.

 

@CrimOudin

Besides necro'ing 2 year old thread... Old internet wisdom - RTFM (read that funky manual) - it is explained in the first two lines of description:
https://docs.unity3d.com/ScriptReference/Color.html

Color values go from 0-1.

But there is also Color32 if you want to use 0-255 value range:
https://docs.unity3d.com/ScriptReference/Color32.html