Unity编辑器拓展之六：利用反射打开Unity Preferences Window

如何利用反射打开Unity Preferences Window

Unity Preferences Window如下图所示：

作为Unity 的参数设置窗口，这个窗口支持新增项，当然本文不介绍这个内容，本次介绍如何利用反射、以及Unity Editor代码来实现用代码打开Preferences Window以及设置选中项。

使用ILSpy工具反编译UnityEditor.dll后呢，在下图目录中的PreferencesWinndow.cs脚本

里面有一个接口是”ShowPreferencesWindow”，从字面上就可以理解到是用来打开PreferencesWindow的。

private static void ShowPreferencesWindow()
{
    EditorWindow window = EditorWindow.GetWindow<PreferencesWindow>(true, "Unity Preferences");
    window.minSize = new Vector2(500f, 400f);
    window.maxSize = new Vector2(window.minSize.x, window.maxSize.y);
    window.position = new Rect(new Vector2(100f, 100f), window.minSize);
    window.m_Parent.window.m_DontSaveToLayout = true;
}

该函数是私有的，没办法直接调，利用反射试一下。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.Reflection;
using System;

public class OpenPreferencesWindow : EditorWindow
{
    [MenuItem("Tool/OpenPreferencesWindow")]
    public static void Open()
    {
        OpenPreferencesWindow editor = EditorWindow.GetWindow<OpenPreferencesWindow>();
    }

    private void OnGUI()
    {
        if (GUILayout.Button("打开PerferencesWindow"))
        {
            Assembly assembly = Assembly.GetAssembly(typeof(UnityEditor.EditorWindow));
            Type type = assembly.GetType("UnityEditor.PreferencesWindow");
            type.GetMethod("ShowPreferencesWindow", BindingFlags.NonPublic | BindingFlags.Static).Invoke(null, null);
        }
    }
}

效果图：

接下来，就是如何实现在打开window之后直接选中某一项。

查看一下OnEnable函数，初始化里面做了啥？

private void OnEnable()
{
    this.prefWinExtensions = ModuleManager.GetPreferenceWindowExtensions();
    this.ReadPreferences();
    this.m_Sections = new List<PreferencesWindow.Section>();
    this.m_Sections.Add(new PreferencesWindow.Section("General", new PreferencesWindow.OnGUIDelegate(this.ShowGeneral)));
    this.m_Sections.Add(new PreferencesWindow.Section("External Tools", new PreferencesWindow.OnGUIDelegate(this.ShowExternalApplications)));
    this.m_Sections.Add(new PreferencesWindow.Section("Colors", new PreferencesWindow.OnGUIDelegate(this.ShowColors)));
    this.m_Sections.Add(new PreferencesWindow.Section("Keys", new PreferencesWindow.OnGUIDelegate(this.ShowKeys)));
    this.m_Sections.Add(new PreferencesWindow.Section("GI Cache", new PreferencesWindow.OnGUIDelegate(this.ShowGICache)));
    this.m_Sections.Add(new PreferencesWindow.Section("2D", new PreferencesWindow.OnGUIDelegate(this.Show2D)));
    if (Unsupported.IsDeveloperBuild() || UnityConnect.preferencesEnabled)
    {
        this.m_Sections.Add(new PreferencesWindow.Section("Unity Services", new PreferencesWindow.OnGUIDelegate(this.ShowUnityConnectPrefs)));
    }
    this.m_RefreshCustomPreferences = true;
}

与PreferencesWindow图对比之后发现，m_Sections这个集合里存的Section对象应该就是Window左侧的可选项了。

接着看看Section这个类

private class Section
{
    public GUIContent content;
    public PreferencesWindow.OnGUIDelegate guiFunc;
    public Section(string name, PreferencesWindow.OnGUIDelegate guiFunc)
    {
        this.content = new GUIContent(name);
        this.guiFunc = guiFunc;
    }
    public Section(string name, Texture2D icon, PreferencesWindow.OnGUIDelegate guiFunc)
    {
        this.content = new GUIContent(name, icon);
        this.guiFunc = guiFunc;
    }
    public Section(GUIContent content, PreferencesWindow.OnGUIDelegate guiFunc)
    {
        this.content = content;
        this.guiFunc = guiFunc;
    }
}

PreferencesWindow在OnEnable的时候，就有实例化几个对象，其中传入的第一个参数，例如“Colors”,就存在类的content中，那么只需要反射到这个content的，再遍历这个m_Sections，就可以实现选中左侧了。

完整代码，如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.Reflection;
using System;

public class OpenPreferencesWindow : EditorWindow
{
    [MenuItem("Tool/OpenPreferencesWindow")]
    public static void Open()
    {
        OpenPreferencesWindow editor = EditorWindow.GetWindow<OpenPreferencesWindow>();
    }

    private void OnGUI()
    {
        if (GUILayout.Button("打开PerferencesWindow"))
        {
            Assembly assembly = Assembly.GetAssembly(typeof(UnityEditor.EditorWindow));
            Type type = assembly.GetType("UnityEditor.PreferencesWindow");
            type.GetMethod("ShowPreferencesWindow", BindingFlags.NonPublic | BindingFlags.Static).Invoke(null, null);

            EditorWindow window = EditorWindow.GetWindow(type);

            FieldInfo sectionsField = type.GetField("m_Sections", BindingFlags.Instance | BindingFlags.NonPublic);
            IList sections = sectionsField.GetValue(window) as IList;

            Type sectionType = sectionsField.FieldType.GetGenericArguments()[0];
            FieldInfo sectionContentField = sectionType.GetField("content", BindingFlags.Instance | BindingFlags.Public);
            for (int i = 0; i < sections.Count; i++)
            {
                GUIContent sectionContent = sectionContentField.GetValue(sections[i]) as GUIContent;
                if (sectionContent.text == "Colors")
                {
                    FieldInfo sectionIndexField = type.GetField("m_SelectedSectionIndex", BindingFlags.Instance | BindingFlags.NonPublic);
                    sectionIndexField.SetValue(window, i);
                    return;
                }
            }
        }
    }
}

效果图：

如果插件中有在PreferencesWindow中添加项，就可以通过这个让用户快捷打开了。

通过这篇文章，希望可以帮助大家学会如何分析反编译出的代码，分析UnityEditor如何实现的编辑器，以此来写出更加实用的插件

以上知识分享，如有错误，欢迎指出，共同学习，共同进步。