Limiting Horizontal Layout Group's Slots

Greetings!

I watched a tutorial on how to do Drag&Drops a few days ago and have now a question. I have several cards in my hand and three different fields, all of them are Horizontal Layout Groups. However, I want to make it so once there's a card inside one of those Groups, you can't put anymore cards in that group until it is empty again. So basically, limit these groups to hold only one card at a time. I've already tried a few things but I can't seem to make it work. How can this be done?

Here's all the code I have at the moment:

Drag.cs

Spoiler

Code (csharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5. using UnityEngine.EventSystems;
6.  
7. public class Drag : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler {
8.  
9.     public Transform parentToReturnTo = null;
10.     public Transform placeholderParent = null;
11.  
12.     public enum Slot {Monster, Item, Spell, Impact, Set};
13.     public Slot CardType = Slot.Monster;
14.  
15.     GameObject placeholder = null;
16.  
17.     public void OnBeginDrag(PointerEventData eventData) {
18.         Debug.Log ("OnBeginDrag");
19.  
20.  
21.  
22.         placeholder = new GameObject ();
23.         placeholder.transform.SetParent (this.transform.parent);
24.  
25.         LayoutElement le = placeholder.AddComponent<LayoutElement> ();
26.  
27.         le.preferredWidth = this.GetComponent<LayoutElement> ().preferredWidth;
28.         le.preferredHeight = this.GetComponent<LayoutElement> ().preferredHeight;
29.         le.flexibleWidth = 0;
30.         le.flexibleHeight = 0;
31.  
32.         placeholder.transform.SetSiblingIndex (this.transform.GetSiblingIndex());
33.  
34.         parentToReturnTo = this.transform.parent;
35.         placeholderParent = parentToReturnTo;
36.  
37.         this.transform.SetParent (this.transform.parent.parent);
38.  
39.         GetComponent<CanvasGroup> ().blocksRaycasts = false;
40.     }
41.  
42.     public void OnDrag(PointerEventData eventData) {
43.         //Debug.Log ("OnDrag");
44.  
45.         this.transform.position = eventData.position;
46.  
47.         if (placeholder.transform.parent != placeholderParent)
48.             placeholder.transform.SetParent (placeholderParent);
49.  
50.         int newSiblingIndex = placeholderParent.childCount;
51.  
52.         for(int i=0; i < placeholderParent.childCount; i++){
53.             if (this.transform.position.x < placeholderParent.GetChild (i).position.x){
54.  
55.                 newSiblingIndex = i;
56.  
57.                 if (placeholder.transform.GetSiblingIndex () < newSiblingIndex)
58.                     newSiblingIndex--;
59.  
60.                 break;
61.             }
62.         }
63.  
64.         placeholder.transform.SetSiblingIndex (newSiblingIndex);
65.     }
66.  
67.     public void OnEndDrag(PointerEventData eventData) {
68.         Debug.Log ("OnEndDrag");
69.  
70.         this.transform.SetParent (parentToReturnTo);
71.         this.transform.SetSiblingIndex (placeholder.transform.GetSiblingIndex());
72.  
73.         GetComponent<CanvasGroup> ().blocksRaycasts = true;
74.         Destroy (placeholder);
75.     }
76. }

Field.cs

Spoiler

Code (csharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.EventSystems;
6.  
7. public class Field : MonoBehaviour, IPointerEnterHandler, IDropHandler, IPointerExitHandler{
8.  
9.     public Drag.Slot CardType = Drag.Slot.Monster;
10.  
11.     public void OnPointerEnter(PointerEventData eventData) {
12.         //Debug.Log ("OnPointerEnter");
13.         if (eventData.pointerDrag == null)
14.             return;
15.  
16.         Drag d = eventData.pointerDrag.GetComponent<Drag> ();
17.  
18.         if (d != null) {
19.             d.placeholderParent = this.transform;
20.         }
21.     }
22.  
23.     public void OnPointerExit(PointerEventData eventData) {
24.         //Debug.Log ("OnPointerExit");
25.         if (eventData.pointerDrag == null)
26.             return;
27.    
28.         Drag d = eventData.pointerDrag.GetComponent<Drag> ();
29.  
30.         if (d != null && d.placeholderParent == this.transform) {
31.             d.placeholderParent = d.parentToReturnTo;
32.         }
33.     }
34.  
35.     public void OnDrop(PointerEventData eventData) {
36.    
37.         Drag d = eventData.pointerDrag.GetComponent<Drag> ();
38.  
39.         if (d != null) {
40.             if (CardType == d.CardType) {
41.                 d.parentToReturnTo = this.transform;
42.                 Debug.Log (eventData.pointerDrag.name + " was dropped on the " + gameObject.name + " as a " + CardType);
43.  
44.             } else {
45.                 Debug.Log (eventData.pointerDrag.name + " can't be dropped on the " + gameObject.name + " as a " + d.CardType);
46.                 return;
47.             }
48.         }
49.     }
50. }

Thank you in advance,
- Nervly

 

Try setting a bool when the group has a card/not. If that bool is set, don't allow the drop to occur and return the card.to where you began dragging it or what not.

 

Thank you, that did the trick!

 

No problem, glad it worked for ya