[SOLVED] UI CANVAS : GameObject.GetComponentsInChildren

Hi,

The code I use allows to enabled/disable a canvas when the camera see a QRCode, until now I used the code below:

Code (CSharp):

1.         //enable canvas
2.         Canvas canvasObject = (Canvas) FindObjectOfType(typeof(Canvas));
3.         {
4.             canvasObject.enabled = true;
5.         }

Code (CSharp):

1.         //disable canvas
2.         Canvas canvasObject = (Canvas) FindObjectOfType(typeof(Canvas));
3.         {
4.             canvasObject.enabled = false;
5.         }

The problem is with several different canvas, Unity enabled/disable just the first canvas found...

I would like to use the function GameObject.GetComponentsInChildren with the canvas instead of the function FindObjectOfType ?

I tried with the help offered by Unity3D website, but without success. Thank you in advance for your help !

 

if you put all your canvases under a single game object, and your script knows about that parent gameobject then the GetComponentInChildren will work for you.

The other option is to specify a list of Canvases to run through. if you know them all at edit time you can do it via the inspector. If you need it at run time you will need to come up with a way to gather all the canvases

 

Thanks @phil-Unity for you answer, but i don't understand your second sentence, i started in Unity3D I would like use the function GetComponentsInChildren with canvasses, but i don't know write the code...

If i put my canvas in a empty "GameObject", this code is correct ?

Code (CSharp):

1.     private void OnTrackingFound()
2.     {
3.         Renderer[] rendererComponents = GetComponentsInChildren<Renderer>(true);
4.         Collider[] colliderComponents = GetComponentsInChildren<Collider>(true);
5.  
6.         //enable canvas
7.                public GameObject[] GameObject;
8.                void Example() {
9.                         GameObject = gameObject.GetComponentsInChildren<GameObject>();
10.         {
11.             gameObject.enabled = true;
12.         }
13.         }
14.     }

 

I usually dont do this as it tends to come back as i dont test the example code i write but something like the following should do what you need.

Code (CSharp):

1. public class MyClass
2. {
3.     public GameObject parentObject;
4.  
5.     public void MyFunction()
6.     {
7.         Canvas[] canvasObjects = parentObject.GetComponentInChildren<Canvas>();
8.        
9.         foreach(Canvas canvas in canvasObjects)
10.         {
11.             canvas.gameobject.enabled = true;
12.         }
13.     }
14. }

 

Thanks @phil-Unity but it doesn't work There are 2 error messages for each "Canvas function" :

Assets/Qualcomm Augmented Reality/Scripts/DefaultTrackableEventHandler.cs(72,26): error CS0029: Cannot implicitly convert type `UnityEngine.Canvas' to `UnityEngine.Canvas[]'

Assets/Qualcomm Augmented Reality/Scripts/DefaultTrackableEventHandler.cs(77,32): error CS1061: Type `UnityEngine.Canvas' does not contain a definition for `gameobject' and no extension method `gameobject' of type `UnityEngine.Canvas' could be found (are you missing a using directive or an assembly reference?)

COMPLETE CODE

Code (CSharp):

1. using UnityEngine;
2.  
3. /// <summary>
4. /// A custom handler that implements the ITrackableEventHandler interface.
5. /// </summary>
6. public class DefaultTrackableEventHandler : MonoBehaviour,
7.                                             ITrackableEventHandler
8. {
9.     #region PRIVATE_MEMBER_VARIABLES
10.     private TrackableBehaviour mTrackableBehaviour;
11.  
12.     #endregion // PRIVATE_MEMBER_VARIABLES
13.  
14.  
15.  
16.     #region UNTIY_MONOBEHAVIOUR_METHODS
17.  
18.     void Start()
19.     {
20.         mTrackableBehaviour = GetComponent<TrackableBehaviour>();
21.         if (mTrackableBehaviour)
22.         {
23.             mTrackableBehaviour.RegisterTrackableEventHandler(this);
24.         }
25.     }
26.  
27.     #endregion // UNTIY_MONOBEHAVIOUR_METHODS
28.  
29.  
30.  
31.     #region PUBLIC_METHODS
32.  
33.     /// <summary>
34.     /// Implementation of the ITrackableEventHandler function called when the
35.     /// tracking state changes.
36.     /// </summary>
37.     public GameObject parentObject;
38.     public void OnTrackableStateChanged(
39.                                     TrackableBehaviour.Status previousStatus,
40.                                     TrackableBehaviour.Status newStatus)
41.     {
42.         if (newStatus == TrackableBehaviour.Status.DETECTED ||
43.             newStatus == TrackableBehaviour.Status.TRACKED ||
44.             newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)
45.         {
46.             OnTrackingFound();
47.         }
48.         else
49.         {
50.             OnTrackingLost();
51.         }
52.     }
53.  
54.     #endregion // PUBLIC_METHODS
55.  
56.  
57.  
58.     #region PRIVATE_METHODS
59.  
60.  
61.     private void OnTrackingFound()
62.     {
63.         Renderer[] rendererComponents = GetComponentsInChildren<Renderer>(true);
64.         Collider[] colliderComponents = GetComponentsInChildren<Collider>(true);
65.         Canvas[] canvasObjects = parentObject.GetComponentInChildren<Canvas>();
66.  
67.  
68.  
69.         //enable canvas
70.  
71.         foreach(Canvas canvas in canvasObjects)
72.  
73.         {
74.  
75.             canvas.gameobject.enabled = true;
76.  
77.         }
78.  
79.         // Enable rendering:
80.         foreach (Renderer component in rendererComponents)
81.         {
82.             component.enabled = true;
83.         }
84.  
85.         // Enable colliders:
86.         foreach (Collider component in colliderComponents)
87.         {
88.             component.enabled = true;
89.         }
90.  
91.         Debug.Log("Trackable " + mTrackableBehaviour.TrackableName + " found");
92.     }
93.  
94.  
95.     private void OnTrackingLost()
96.     {
97.         Renderer[] rendererComponents = GetComponentsInChildren<Renderer>(true);
98.         Collider[] colliderComponents = GetComponentsInChildren<Collider>(true);
99.         Canvas[] canvasObjects = parentObject.GetComponentInChildren<Canvas>();
100.  
101.  
102.  
103.         //disable canvas
104.  
105.         foreach(Canvas canvas in canvasObjects)
106.  
107.         {
108.  
109.             canvas.gameobject.enabled = false;
110.  
111.         }
112.  
113.         // Disable rendering:
114.         foreach (Renderer component in rendererComponents)
115.         {
116.             component.enabled = false;
117.         }
118.  
119.         // Disable colliders:
120.         foreach (Collider component in colliderComponents)
121.         {
122.             component.enabled = false;
123.         }
124.  
125.         Debug.Log("Trackable " + mTrackableBehaviour.TrackableName + " lost");
126.     }
127.  
128.     #endregion // PRIVATE_METHODS
129. }

 

Canvas[] canvasObjects = parentObject.GetComponentInChildren<Canvas>(); should be Canvas[] canvasObjects = parentObject.GetComponentsInChildren<Canvas>(); (notice the s on components)


canvas.gameobject.enabled=true; needs to be canvas.gameObject.enabled=true; (notice the capital O in gameObject).

This is the exact reason i dont try to write code examples as if i miss one letter or capitalization it always comes back .

 

Thanks a lot @phil-Unity, it works !

I custom a little bit your code

Code (CSharp):

1.         Canvas[] canvasObjects = GetComponentsInChildren<Canvas>();
2.  
3.         //enable canvas
4.         foreach(Canvas canvas in canvasObjects)
5.         {
6.             canvas.enabled = true;
7.         }

Code (CSharp):

1.         Canvas[] canvasObjects = GetComponentsInChildren<Canvas>();
2.  
3.         //disable canvas
4.         foreach(Canvas canvas in canvasObjects)
5.         {
6.             canvas.enabled = false;
7.         }