让Unity的Inspector面板支持字符限制(restrict)功能

今天在优化红点组件，笔者打算将红点id由10进制改成16进制处理，就打算将红点id字段由uint类型改为string类型，用于填写16进制的字符（由于在Inspector面板里，uint/int类型字段不能直接填写16进制表示的数字），且但愿限制该字段的输入限制，仅限于填写0-9A-Fa-f等16进制字符串，但unity并无提供任何PropertyAttribute类来限制字符输入，达到相似于as3 text组件的restrict效果。所以笔者自定义了一个RestrictAttribute类，用于实现字符限制效果。

/* ==============================================================================
     * 功能描述：限制string字段的输入类型
     * 创 建 者：shuchangliu
     * ==============================================================================*/

    using System.Text.RegularExpressions;
    using UnityEngine;
    #if UNITY_EDITOR
    using UnityEditor;
    #endif

    public class RestrictAttribute : PropertyAttribute
    {
        public string restrict;
        // Use this for initialization
        public RestrictAttribute(string restrict)
        {
            this.restrict = restrict;
        }
    }

    #if UNITY_EDITOR
    [CustomPropertyDrawer(typeof(RestrictAttribute))]
    public class RestrictDrawer : PropertyDrawer
    {
        public override float GetPropertyHeight(SerializedProperty property,
                                                GUIContent label)
        {
            return EditorGUI.GetPropertyHeight(property, label, true);
        }

        public override void OnGUI(Rect position,
                                   SerializedProperty property,
                                   GUIContent label)
        {
            RestrictAttribute a = attribute as RestrictAttribute;

            EditorGUI.PropertyField(position, property, label, true);
            string v = property.stringValue;
            v = Regex.Replace(v, @"[^" + a.restrict + "]*", "");
            property.stringValue = v;
        }

    }
    #endif

---

public class Test : MonoBehaviour
    {
        [Restrict("0-9a-fA-F")]
        public string pid;
    }

在字段前加上[Restrict(string str)]参数，pid就只能够输入16进制数字(0-9及a-f的大小英文)了