Reorderable list of UnityEvents

Question

Hi! I'm a bit of a novice with C# but I'm very familiar with many of the Unity tools and concepts. I'd appreciate some help!

I've been following this tutorial, but it doesn't work well when I swap simple variables like floats and strings out for Unity Events.

My goal:

I'm making a scripted event system which could be triggered from anything. It should fire off a list of Unity Events with delays between each one. It should have a custom inspector component so that the list is reorderable.

My problem:

Correctly displaying this list as a Reorderable List in a custom Inspector component.

My setup:

I've created a struct, which uses a UnityEvent (the action) and a float (the delay) for each object in the list.

I then have another script as a container (I think? not too sure of the correct terminology there) which iterates through the list and calls each event in order.

This works exactly how I want it to, but the Inspector tools for this are a bit difficult to work with because it's not reorderable. Here's how it looks by default:

alt text

When I add the custom editor script, everything overlaps each other. Here's the same list with the custom inspector:

alt text

Here's all the code:

The event struct:

 using UnityEngine;
 using UnityEngine.Events;
 using System;
 
 // An event which can be called as part of a Scripted Sequence
 
 [Serializable]
 public struct ScriptedSequenceEvent {
     public float delay;
     public UnityEvent scriptedEvent;
 }

Container for the events. Also processes the list when I call the Scripted Sequence:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 // A container for the events
 
 public class ScriptedSequence : MonoBehaviour {
 
     private IEnumerator sequenceCoroutine;
 
     public bool startAutomatically;
     public bool onlyTriggerOnce;
     private bool started = false;
 
     // The list of events
     public List<ScriptedSequenceEvent> events = new List<ScriptedSequenceEvent>();
 
     void Start () {
         if (startAutomatically)
             StartScriptedSequence ();        
     }
 
     public void StartScriptedSequence () {
         if (!onlyTriggerOnce) {
             BeginSequence ();
         } else {
             if (!started) {
                 BeginSequence ();
             }
         }
     }
 
     void BeginSequence () {
         started = true;
         sequenceCoroutine = ProcessSequence ();
         StartCoroutine (sequenceCoroutine);
     }
         
     private IEnumerator ProcessSequence () {
         int i = 0;
         // Iterate through each item in the list.
         foreach(ScriptedSequenceEvent currentEvent in events) {
             // Wait for the delay, if it's > 0.
             if (currentEvent.delay > 0f)
                 yield return new WaitForSeconds (currentEvent.delay);
             // Invoke the event.
             currentEvent.scriptedEvent.Invoke ();
             // Increase the current iteration number so we move on to the next one in the next loop.
             i++;
         }
     }
 }

Custom Inspector code:

 using UnityEngine;
 using UnityEditor;
 using UnityEditorInternal;
 
 // The custom inspector script which lets use make the list of events reorderable, and lets us draw it how we want.
 
 [CustomEditor(typeof(ScriptedSequence))]
 public class ScriptedSequence_Editor : Editor {
 
     private ReorderableList list;
 
     private void OnEnable() {
 
         // Create the list
         list = new ReorderableList (serializedObject, serializedObject.FindProperty ("events"), true, true, true, true);
 
         // Draw header label
         list.drawHeaderCallback = (Rect rect) => {
             EditorGUI.LabelField(rect, "Events");
         };
 
         // Draw each element in the list
         list.drawElementCallback = 
             (Rect rect, int index, bool isActive, bool isFocused) => {
             var element = list.serializedProperty.GetArrayElementAtIndex(index);
             rect.y += 2;
             
             EditorGUI.PropertyField (
                 new Rect(rect.x, rect.y, rect.width - 30, EditorGUIUtility.singleLineHeight),
                 element.FindPropertyRelative("scriptedEvent"), GUIContent.none);
 
             EditorGUI.PropertyField (
                 new Rect(rect.x + rect.width - 25, rect.y, 25, EditorGUIUtility.singleLineHeight),
                 element.FindPropertyRelative("delay"), GUIContent.none);
         };
     }
 
     public override void OnInspectorGUI() {
         serializedObject.Update ();
         list.DoLayoutList ();
         serializedObject.ApplyModifiedProperties ();
     }
 }

Thanks in advance! :)

Answer 1

Best Answer

Answer by Adam-Mechtley · May 01, 2017 at 05:19 PM

On your ReorderableList instance, you need to assign something to either elementHeight (when everything has the same height) or elementHeightCallback (when individual elements may have different heights).

1 Show 5 · Share

CrowbarSka · May 01, 2017 at 05:51 PM 0

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Thanks!

elementHeight prevented the problem when I add more elements to the list, but the elements can change height when I add multiple events to each element, so it seems like I neeed elementHeightCallback.

Any chance you could give me some pointers for how to implement this?

Adam-Mechtley CrowbarSka · May 01, 2017 at 05:56 PM 1

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It works like any of other callback functions, and most times if you are using e.g., default PropertyDrawers it is sufficient to do something like this:

 list.elementHeightCallback = delegate(int index) {
     var element = list.serializedProperty.GetArrayElementAtIndex(index);
     var elementHeight = EditorGUI.GetPropertyHeight(element);
     // optional, depending on the situation in question and the defaults you like
     // you may want to subtract the margin out in the drawElementCallback before drawing
     var margin = EditorGUIUtility.standardVerticalSpacing;
     return elementHeight + margin;
 };

CrowbarSka Adam-Mechtley · May 01, 2017 at 11:09 PM 0

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Thank you, that code fixed the element height when I add multiple events to each element. However, I still get this issue when I add more elements to the list:

alt text

I guess what I'm looking for is some understanding of how these callbacks work, and how I can add my own and configure them to my needs.

editor5.png (89.5 kB)

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Answer 2

@CrowbarSka this should work

 using UnityEngine;
 using UnityEditor;
 using UnityEditorInternal;
 
 [CustomEditor(typeof(ScriptedSequence))]
 public class ScriptedSequence_Editor : Editor
 {
     private ReorderableList list;
     private ScriptedSequence scriptedSequence;
 
     private void OnEnable()
     {
         scriptedSequence = target as ScriptedSequence;
         // Create the list
         list = new ReorderableList(serializedObject, serializedObject.FindProperty("events"), true, true, true, true);
         
 
     }
 
     private void DrawList()
     {
         // Draw header label
         list.drawHeaderCallback = (Rect rect) =>
         {
             EditorGUI.LabelField(rect, "Events");
         };
 
         // Draw each element in the list
         list.drawElementCallback =
             (Rect rect, int index, bool isActive, bool isFocused) =>
             {
                 var element = list.serializedProperty.GetArrayElementAtIndex(index);
                 rect.y += 2;
 
                 EditorGUI.PropertyField(
                      new Rect(rect.x, rect.y, rect.width - 30, EditorGUI.GetPropertyHeight(element,true)),
                      element.FindPropertyRelative("scriptedEvent"), GUIContent.none);
 
                 EditorGUI.PropertyField(
                      new Rect(rect.x + rect.width - 25, rect.y, 25, EditorGUIUtility.singleLineHeight),
                      element.FindPropertyRelative("delay"), GUIContent.none);
             };
 
         list.elementHeightCallback = (int index) =>
         {
             var elementHeight = scriptedSequence.events[index].scriptedEvent.GetPersistentEventCount();
             if (elementHeight >= 1)
             {
                 elementHeight--;
             }
             return (EditorGUIUtility.singleLineHeight * 5) + elementHeight * (EditorGUIUtility.singleLineHeight * 2.7f);
         };
     }
 
     public override void OnInspectorGUI()
     {
         serializedObject.Update();
         DrawList();
         list.DoLayoutList();
         serializedObject.ApplyModifiedProperties();
     }
 }

Reorderable list of UnityEvents

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