PropertyDrawer To UI Toolkit: Tracking Object Changes

by SLV Team 54 views

Hey guys! So, you're diving into the Unity world, and you've got this awesome collection of PropertyDrawer scripts you've been rocking for ages. Now, with the new UI Toolkit, you might be wondering, "How can I translate my old PropertyDrawer magic into this new system, and how do I keep tabs on changes in my objects, like those pesky AssetBundles?" Well, let's break it down! We'll explore transitioning from PropertyDrawer to the UI Toolkit and discuss how to effectively monitor object modifications in your Unity editor. This is crucial for keeping your editor tools snappy and responsive!

Transitioning from PropertyDrawer to UI Toolkit

Alright, so you've got your trusty PropertyDrawer scripts. They're probably doing a fantastic job of customizing how your data appears in the Inspector. But now, UI Toolkit is here, and it's time to consider the switch. Think of it like moving from an old, comfy house to a sleek, modern apartment. You might miss some of the old charm, but the new place offers some serious upgrades. With UI Toolkit, you'll gain access to a more modern and flexible system for creating custom editor interfaces. So, let's explore how to get your PropertyDrawer scripts ready for the UI Toolkit!

  • Understanding the Basics: First things first, get familiar with the core concepts of UI Toolkit. The UI Toolkit uses a different set of classes and methods compared to the old Editor GUI system. Instead of EditorGUI.PropertyField, you'll be dealing with VisualElement and IMGUIContainer, among other things. UI Toolkit builds interfaces with a hierarchical structure of elements, similar to HTML and CSS. You'll create and arrange UI elements using code or by defining them in a UXML file. This can lead to a more organized and maintainable editor UI.

  • Replacing PropertyDrawer Logic: Your existing PropertyDrawer scripts likely handle displaying and editing properties within the Inspector. In the UI Toolkit, you will need to create a VisualElement-based custom editor to display your properties. This involves the following:

    • Create a Custom Editor: You'll need to write an editor script. This script will determine how a specific component or asset appears and behaves in the Inspector.
    • Implement a CreateInspectorGUI() Method: This is where you'll build your UI. You'll create and arrange visual elements, such as labels, text fields, buttons, and other controls, to display and edit your properties. You can use code, UXML files, or a mix of both to design the user interface.
    • Bind Properties to UI Elements: You'll need to bind your properties (from the inspected object) to your UI elements. This will allow you to display and modify the values in the inspector. You can use methods to read values from the serialized object.

  • Example: From PropertyDrawer to UI Toolkit: Let's say your PropertyDrawer displays a custom Color field. Here’s a basic idea of how you could adapt it to UI Toolkit:

    // Old PropertyDrawer (Simplified)
[CustomPropertyDrawer(typeof(MyCustomClass))]
public class MyCustomClassDrawer : PropertyDrawer
{
    public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
    {
        EditorGUI.BeginProperty(position, label, property);
        // Display your custom controls here
        EditorGUI.EndProperty();
    }
}

// New UI Toolkit Editor (Simplified)
[CustomEditor(typeof(MyCustomClass))]
public class MyCustomClassEditor : Editor
{
    public override VisualElement CreateInspectorGUI()
    {
        var root = new VisualElement();
        // Build your UI using VisualElements, e.g., TextField, ColorField
        var myColorProperty = serializedObject.FindProperty("myColor");
        var colorField = new ColorField{ label = "My Color" };
        colorField.BindProperty(myColorProperty);
        root.Add(colorField);
        return root;
    }
}

    In the UI Toolkit example, we replace the OnGUI method with CreateInspectorGUI. We build the UI using VisualElement objects. We also retrieve the SerializedProperty and bind it to UI elements like ColorField to edit properties.

Challenges and Considerations

  • Learning Curve: UI Toolkit has a learning curve. You'll need to familiarize yourself with the new API and concepts, such as VisualElement, UXML, and USS (UI Style Sheets).
  • Compatibility: While Unity is working on making UI Toolkit compatible with various aspects of the editor, there might be some limitations. Make sure the features you need are fully supported.
  • Complexity: As your custom editor becomes more complex, maintaining it in the UI Toolkit might seem challenging. Consider breaking down your custom UI elements into smaller, reusable components to improve the code organization.

By carefully refactoring your existing PropertyDrawer scripts and embracing the power of UI Toolkit, you can modernize your Unity editor tools, leading to enhanced customization, improved performance, and a more user-friendly workflow for your team!

Tracking Changes in Linked Objects

Now, the other big question: How do you keep tabs on changes in linked objects, like those pesky AssetBundles or anything else that changes outside the immediate Inspector? This is crucial for making sure your editor tools are always up-to-date. In editor scripting, you often need to detect when the user modifies objects in the scene, project, or associated assets. Here's a breakdown of the techniques and best practices to keep your editor tools reactive and in sync with external changes.

  • Using EditorApplication.update: This is your workhorse for continuous monitoring. This method runs every frame in the editor, allowing you to check for changes.

    using UnityEditor;
using UnityEngine;

public class MyEditorScript : EditorWindow
{
    private static bool _needsRepaint;

    [MenuItem("Window/My Editor Window")]
    public static void ShowWindow()
    {
        GetWindow<MyEditorScript>("My Editor");
    }

    private void OnEnable()
    {
        EditorApplication.update -= OnEditorUpdate; // Ensure no duplicates.
        EditorApplication.update += OnEditorUpdate;
    }

    private void OnDisable()
    {
        EditorApplication.update -= OnEditorUpdate;
    }

    private void OnEditorUpdate()
    {
        // Check for changes here
        if (_needsRepaint)
        {
            Repaint(); // Force the editor window to repaint.
            _needsRepaint = false;
        }
    }

    private void OnGUI()
    {
        GUILayout.Label("Changes detected.");
    }

    // Example: Check for changes in a specific asset
    public static void CheckForAssetChanges(string assetPath)
    {
        // Use AssetDatabase.GetAssetPath and check if the asset has been changed
        // For simplicity, we just set a flag here.
        _needsRepaint = true;
    }
}
    • Inside OnEditorUpdate, you'll constantly monitor the state of your objects. This method will be called very often, so keep it optimized. Check only what's needed. If an event occurs, it sets a flag and calls Repaint().
    • Repaint() tells the editor to redraw your window or Inspector, reflecting the changes. Remember to unregister from EditorApplication.update in OnDisable to avoid memory leaks.

  • AssetDatabase Events: AssetDatabase is your friend when it comes to assets. It provides events that fire when assets are created, moved, deleted, or changed.

    using UnityEditor;
using UnityEngine;

public class AssetChangeMonitor
{
    [InitializeOnLoadMethod]
    static void Initialize()
    {
        AssetDatabase.importAssetCompleted += OnAssetImported; // For assets imported
        AssetDatabase.assetMoved += OnAssetMoved; // When assets are moved
        AssetDatabase.assetDeleted += OnAssetDeleted; // When assets are deleted
    }

    static void OnAssetImported(string assetPath)
    {
        // React to asset import completion
        Debug.Log({{content}}quot;Asset imported: {assetPath}");
        // Refresh your editor's data/display as needed
    }

    static void OnAssetMoved(string oldPath, string newPath)
    {
        Debug.Log({{content}}quot;Asset moved from {oldPath} to {newPath}");
    }

    static void OnAssetDeleted(string assetPath, RemoveAssetOptions options)
    {
        Debug.Log({{content}}quot;Asset deleted: {assetPath}");
    }
}
    • AssetDatabase.importAssetCompleted: Fires after an asset is imported (e.g., from an external file).
    • AssetDatabase.assetMoved: Fires when an asset's location changes.
    • AssetDatabase.assetDeleted: Fires when an asset is deleted. [InitializeOnLoadMethod] makes sure your static class is loaded as soon as the editor starts.

  • Scene Management Events: Use the EditorSceneManager class to hook into scene-related events.

    using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;

public class SceneChangeMonitor
{
    [InitializeOnLoadMethod]
    static void Initialize()
    {
        EditorSceneManager.sceneOpened += OnSceneOpened;
        EditorSceneManager.sceneClosed += OnSceneClosed;
        EditorSceneManager.sceneSaved += OnSceneSaved;
        EditorSceneManager.sceneLoaded += OnSceneLoaded;
    }

    static void OnSceneOpened(Scene scene, OpenSceneMode mode)
    {
        Debug.Log({{content}}quot;Scene opened: {scene.name}");
        // Update your UI as needed
    }

    static void OnSceneClosed(Scene scene)
    {
        Debug.Log({{content}}quot;Scene closed: {scene.name}");
    }

    static void OnSceneSaved(Scene scene)
    {
        Debug.Log({{content}}quot;Scene saved: {scene.name}");
    }

    static void OnSceneLoaded(Scene scene, LoadSceneMode mode)
    {
        Debug.Log({{content}}quot;Scene loaded: {scene.name}");
    }
}
    • EditorSceneManager.sceneOpened: When a scene is opened.
    • EditorSceneManager.sceneClosed: When a scene is closed.
    • EditorSceneManager.sceneSaved: When a scene is saved.
    • EditorSceneManager.sceneLoaded: When a scene is loaded.

  • Considerations and Best Practices:

    • Performance is Key: Monitoring should be efficient to avoid slowing down the editor. Avoid doing heavy operations inside event handlers. If you need to do something time-consuming, queue it up (e.g., using EditorApplication.delayCall) or use Task to run it on a separate thread (but remember that only the main thread can update Unity objects!).
    • Caching: If you're checking object properties, cache relevant data instead of constantly querying for it. Update your cache when you detect a change.
    • Filtering: Be specific about what you monitor. Don't check everything all the time. Filter your checks to the relevant objects or paths.
    • Editor Windows: Create a dedicated editor window to provide real-time information to the user. This window can display details about monitored assets or objects, allowing for visual feedback on changes.

Conclusion

So, there you have it! Transitioning from PropertyDrawer to the UI Toolkit and keeping tabs on object changes in Unity is totally achievable. With a bit of work and by leveraging the power of EditorApplication.update, AssetDatabase events, and scene management events, you can create robust editor tools. Good luck, and happy coding! Don't be afraid to experiment and to consult the Unity documentation or the Unity community for support. Creating custom editor tools can significantly improve your workflow and overall development experience. Now go forth and create some awesome stuff!