UIToolkit, QoL extension methods that should be built-in

ExtensionMethods_UIToolkit.cs

// src* = https://gist.github.com/andrew-raphael-lukasik/d38a11bf0559a723617b9deaeedb2eac
using UnityEngine;
using UnityEngine.UIElements;

public static class ExtensionMethods_UIToolkit
{

	public static bool Q<T>(this VisualElement root, string name, out T result, params string[] classes)
		where T : VisualElement
	{
		result = root.Find<T>(name, classes);
		bool found = result != null;
		
		if( !found ) Debug.LogWarning($"no <{typeof(T).Name}> name:{name} classes:{JsonUtility.ToJson(classes)} found!");
		
		return found;
	}
	public static bool Q<T>(this VisualElement root, out T result, params string[] classes)
		where T : VisualElement
	{
		result = root.Find<T>(null, classes);
		bool found = result != null;
		
		if( !found ) Debug.LogWarning($"no <{typeof(T).Name}> classes:{JsonUtility.ToJson(classes)} found!");
		
		return found;
	}

	public static T For<T>(this VisualElement root, string name, System.Action<T> action, params string[] classes)
		where T : VisualElement
	{
		T result = root.Find<T>(name, classes);
		if (result != null)
		{
			if (action != null)
				action(result);

			int numFound = root.Query<T>(name, classes).ToList().Count;
			if (numFound == 0) Debug.LogWarning($"no <{typeof(T).Name}> name:{name} classes:{JsonUtility.ToJson(classes)} found!");
			else if (numFound != 1) Debug.LogWarning($"number of <{typeof(T).Name}> name:{name} classes:{JsonUtility.ToJson(classes)} found is {numFound} where only 1 was expected");
		}
		return result;
	}

	public static T Find<T>(this VisualElement root, string name, params string[] classes)
		where T : VisualElement
	{
		T result = default(T);
		if (root != null)
		{
			result = UQueryExtensions.Q<T>(root, name, classes);
			if (result == null) Debug.LogWarning($"{root.name}.'{name}'<{typeof(T).Name}> classes:{JsonUtility.ToJson(classes)} not found");
		}
		else Debug.LogWarning($"given {nameof(root)} is null!");
		return result;
	}
	public static T Find<T>(this VisualElement root, params string[] classes)
		where T : VisualElement
		=> Find<T>(root, null, classes);

	public static void Foreach<T>(this VisualElement root, string name, System.Action<T> action, params string[] classes)
		where T : VisualElement
	{
		var query = root.Query<T>(name, classes);
		int numFound = query.ToList().Count;
		if (numFound == 0) Debug.LogWarning($"no <{typeof(T).Name}> name:{name} classes:{JsonUtility.ToJson(classes)} found!");
		else if (numFound != 1) Debug.LogWarning($"number of <{typeof(T).Name}> name:{name} classes:{JsonUtility.ToJson(classes)} found is {numFound} where only 1 was expected");
		query.ForEach(action);
	}
	public static void Foreach<T>(this VisualElement root, System.Action<T> action, params string[] classes)
		where T : VisualElement
		=> Foreach<T>(root, action, classes);

}

if( ROOT.Q<Button>( "button-name" , out var button ) )
	button.clicked += () => Debug.Log("button clicked");

Main utility here is that when this Q fails it won't throw exceptions (breaking everything) and will log you an informative message about it so you don't need to write a code to handle that detail everywhere.

Thanks for sharing this. It's a great idea and fits nicely into all my current usages and they just start taking advantage of it right away. 👍

Hi, happy to hear it's useful!

I feel obliged to note that one cool thing I totally missed while writing this piece was a ForEach query present in the API. It's very easy to miss if you ask me:

ROOT.Query<Button>( "button-name" ).ForEach( (button) =>
{
	button.clicked += () => Debug.Log("button clicked");
} );

It executes for each matching element (if found any), which is irreplaceable in some cases.

Yes, I am very much a fan of that one. I use it quite often when setting up animations on a large number of elements and things of that nature. Or, at least a "close enough" approach.

https://github.com/instance-id/ElementAnimationToolkit/blob/9174582bad733f90626810055dca2f149e883477/Assets/instance.id/ElementAnimationToolkit/Runtime/Scripts/UI/EATKEditor.cs#L887