PropertyField problem

Questions & Answers
1

I want to show some properties in an inspector only if I select a specific enum index, so if I don’t select that enum index these properties will be hidden.
I found a script in internet and edited in this way:
using UnityEngine;
using UnityEditor;

[CustomEditor(typeof(Trigger_DoorState)), CanEditMultipleObjects]
public class TriggerScriptsEditor : Editor {

	public SerializedProperty
	TriggerInteraction_prop,
	itemTrigger_prop,
	useItemArea_prop,
	switchObject_prop;

	void OnEnable () {
		TriggerInteraction_prop = serializedObject.FindProperty ("type");
		itemTrigger_prop = serializedObject.FindProperty ("pickUpItem");
		useItemArea_prop = serializedObject.FindProperty("useItem");
		switchObject_prop = serializedObject.FindProperty ("switch");   
	}

	public override void OnInspectorGUI() {
		serializedObject.Update ();

		EditorGUILayout.PropertyField(TriggerInteraction_prop);

		Trigger_DoorState.InteractionType st = (Trigger_DoorState.InteractionType)TriggerInteraction_prop.intValue;

		switch( st ) {
		case Trigger_DoorState.InteractionType.OnPickUpItem:            
			EditorGUILayout.PropertyField( itemTrigger_prop, new GUIContent("pickUpItem") );            
			break;

		case Trigger_DoorState.InteractionType.OnUseItem:            
			EditorGUILayout.PropertyField( useItemArea_prop, new GUIContent("useItem") );    
			break;

		case Trigger_DoorState.InteractionType.OnSwitch:            
			EditorGUILayout.PropertyField( switchObject_prop, new GUIContent("switch") );    
			break;
		}
		serializedObject.ApplyModifiedProperties ();
	}
}

Anyway, this script doesn’t work and an error message appears:

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.PropertyHandler.OnGUILayout (UnityEditor.SerializedProperty property, UnityEngine.GUIContent label, Boolean includeChildren, UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Editor/Mono/ScriptAttributeGUI/PropertyHandler.cs:190)
UnityEditor.EditorGUILayout.PropertyField (UnityEditor.SerializedProperty property, UnityEngine.GUIContent label, Boolean includeChildren, UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Editor/Mono/EditorGUI.cs:7296)
UnityEditor.EditorGUILayout.PropertyField (UnityEditor.SerializedProperty property, UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Editor/Mono/EditorGUI.cs:7278)
TriggerScriptsEditor.OnInspectorGUI () (at Assets/Editor/TriggerScriptsEditor.cs:23)
UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor editor, Int32 editorIndex, Boolean rebuildOptimizedGUIBlock, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1235)
UnityEditor.DockArea:OnGUI()

Please help me, i don’t understand the problem.

2

Your problem is on line 23 of TriggerScriptsEditor.cs. I don’t know if your line numbers here match up exactly, but juts verify in OnEnable that each of those SerializedProperty fields you initialize is not null.