ReadOnly property drawer for Unity~ Add a [ReadOnly] attribute to a property to make it show up as read only in the inspector

ReadOnlyAttribute.cs

// NOTE DONT put in an editor folder

using UnityEngine;
public class ReadOnlyAttribute : PropertyAttribute { }

ReadOnlyPropertyDrawer.cs

// NOTE put in a Editor folder

using UnityEngine;
using UnityEditor;
using System.Collections;

[CustomPropertyDrawer(typeof(ReadOnlyAttribute))]
public class ReadOnlyPropertyDrawer : PropertyDrawer 
{
	public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
	{
		GUI.enabled = false;
		EditorGUI.PropertyField(position, property, label);
		GUI.enabled = true;
	}
}

@ZiadJ

clutter things up with additional files

It is actually better/cleaner coding to have one file for each class instead of having multiple classes in one single file ;)

Unfortunately it doesn't fully work for Lists:

[ReadOnly] public List<int> test = new List<int>(){ 1,2,3};

The most "dangerous" value to change is till available.

---

And it especially doesn't work for nested elements:

where the elements are of type

[Serializable]
public class TestClass
{
    public int num;
    public string text;
}

[ReadOnly] public List<TestClass> test = new List<TestClass>(){
    new TestClass(),
    new TestClass{num = 2, text = "Hi"},
    new TestClass{num = 3, text = "asd"}
};

also if it is not in a list like

[ReadOnly] public TestClass test = new TestClass();

Paste this code into ReadOnlyPropertyDrawer and it will fix, worked in my case btw.

`

public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
{
    GUI.enabled = false;
    EditorGUI.PropertyField(position, property, label, true);
    GUI.enabled = true;
}

public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
{
    return EditorGUI.GetPropertyHeight(property, label, true);
}

`

Here is the inspector after modification