Add Dropdown attribute

Editor.Extras/Drawers/DropdownDrawer.cs

@@ -0,0 +1,190 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using TriInspector;
+using TriInspector.Drawers;
+using TriInspector.Resolvers;
+using UnityEditor;
+using UnityEngine;
+
+[assembly: RegisterTriAttributeDrawer(typeof(DropdownDrawer), TriDrawerOrder.Decorator)]
+
+namespace TriInspector.Drawers
+{
+    public class DropdownDrawer : TriAttributeDrawer<DropdownAttribute>
+    {
+        private DropdownResolver _resolver;
+
+        public override TriExtensionInitializationResult Initialize(TriPropertyDefinition propertyDefinition)
+        {
+            _resolver = DropdownResolver.Create(typeof(DropdownValueResolver<>), propertyDefinition, Attribute.Values);
+
+            if (_resolver.TryGetErrorString(out var error))
+            {
+                _resolver = DropdownResolver.Create(typeof(DropdownItemResolver<>), propertyDefinition,
+                    Attribute.Values);
+
+                if (_resolver.TryGetErrorString(out error))
+                {
+                    return error;
+                }
+            }
+
+            return TriExtensionInitializationResult.Ok;
+        }
+
+        public override TriElement CreateElement(TriProperty property, TriElement next)
+        {
+            return new DropdownElement(property, _resolver);
+        }
+
+        private class DropdownElement : TriElement
+        {
+            private readonly TriProperty _property;
+            private readonly DropdownResolver _resolver;
+
+            private string _currentText;
+
+            public DropdownElement(TriProperty property, DropdownResolver resolver)
+            {
+                _property = property;
+                _resolver = resolver;
+            }
+
+            protected override void OnAttachToPanel()
+            {
+                base.OnAttachToPanel();
+
+                _property.ValueChanged += OnValueChanged;
+
+                RefreshCurrentText();
+            }
+
+            protected override void OnDetachFromPanel()
+            {
+                _property.ValueChanged -= OnValueChanged;
+
+                base.OnDetachFromPanel();
+            }
+
+            public override float GetHeight(float width)
+            {
+                return EditorGUIUtility.singleLineHeight;
+            }
+
+            public override void OnGUI(Rect position)
+            {
+                var controlId = GUIUtility.GetControlID(FocusType.Passive);
+                position = EditorGUI.PrefixLabel(position, controlId, _property.DisplayNameContent);
+
+                if (GUI.Button(position, _currentText, EditorStyles.popup))
+                {
+                    ShowDropdown(position);
+                }
+            }
+
+            private void OnValueChanged(TriProperty property)
+            {
+                RefreshCurrentText();
+            }
+
+            private void RefreshCurrentText()
+            {
+                var items = _resolver.GetDropdownItems(_property);
+
+                _currentText = items
+                    .FirstOrDefault(it => _resolver.EqualityComparer.Equals(it.Value, _property.Value))
+                    ?.Text ?? "";
+            }
+
+            private void ShowDropdown(Rect position)
+            {
+                var items = _resolver.GetDropdownItems(_property);
+                var menu = new GenericMenu();
+
+                foreach (var item in items)
+                {
+                    var isOn = _resolver.EqualityComparer.Equals(item.Value, _property.Value);
+                    menu.AddItem(new GUIContent(item.Text), isOn, _property.SetValue, item.Value);
+                }
+
+                menu.DropDown(position);
+            }
+        }
+
+        private abstract class DropdownResolver
+        {
+            public abstract IEqualityComparer EqualityComparer { get; }
+
+            public abstract void Initialize(TriPropertyDefinition propertyDefinition, string expression);
+
+            public abstract bool TryGetErrorString(out string error);
+
+            public abstract IEnumerable<ITriDropdownItem> GetDropdownItems(TriProperty property);
+
+            public static DropdownResolver Create(Type resolverType,
+                TriPropertyDefinition propertyDefinition, string expression)
+            {
+                var elementType = propertyDefinition.FieldType;
+                var resolver = (DropdownResolver) Activator.CreateInstance(resolverType.MakeGenericType(elementType));
+                resolver.Initialize(propertyDefinition, expression);
+                return resolver;
+            }
+        }
+
+        private class DropdownItemResolver<T> : DropdownResolver
+        {
+            private ValueResolver<IEnumerable<TriDropdownItem<T>>> _resolver;
+
+            public override IEqualityComparer EqualityComparer { get; } = EqualityComparer<T>.Default;
+
+            public override void Initialize(TriPropertyDefinition propertyDefinition, string expression)
+            {
+                _resolver = ValueResolver.Resolve<IEnumerable<TriDropdownItem<T>>>(propertyDefinition, expression);
+            }
+
+            public override bool TryGetErrorString(out string error)
+            {
+                return _resolver.TryGetErrorString(out error);
+            }
+
+            public override IEnumerable<ITriDropdownItem> GetDropdownItems(TriProperty property)
+            {
+                var values = _resolver.GetValue(property, Enumerable.Empty<TriDropdownItem<T>>());
+
+                foreach (var value in values)
+                {
+                    yield return value;
+                }
+            }
+        }
+
+        private class DropdownValueResolver<T> : DropdownResolver
+        {
+            private ValueResolver<IEnumerable<T>> _resolver;
+
+            public override IEqualityComparer EqualityComparer { get; } = EqualityComparer<T>.Default;
+
+            public override void Initialize(TriPropertyDefinition propertyDefinition, string expression)
+            {
+                _resolver = ValueResolver.Resolve<IEnumerable<T>>(propertyDefinition, expression);
+            }
+
+            public override bool TryGetErrorString(out string error)
+            {
+                return _resolver.TryGetErrorString(out error);
+            }
+
+            public override IEnumerable<ITriDropdownItem> GetDropdownItems(TriProperty property)
+            {
+                var values = _resolver.GetValue(property, Enumerable.Empty<T>());
+
+                foreach (var value in values)
+                {
+                    yield return new TriDropdownItem {Text = $"{value}", Value = value,};
+                }
+            }
+        }
+    }
+}

Editor.Extras/Drawers/DropdownDrawer.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 355fb8aedd1f4aca846a8bbf96558a5d
+timeCreated: 1656941791

Editor.Samples/Decorators.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: f3a78924b3514722b6a7e06f0c77121d
+timeCreated: 1656933680

Editor.Samples/Decorators/Decorators_DropdownSample.cs

@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using TriInspector;
+using UnityEngine;
+
+public class Decorators_DropdownSample : ScriptableObject
+{
+    [Dropdown(nameof(_intValues))]
+    public int intValue = 1;
+
+    [Dropdown(nameof(GetStringValues))]
+    public string stringValue;
+
+    [Dropdown(nameof(GetVectorValues))]
+    public Vector3 vectorValue;
+
+    private int[] _intValues = {1, 2, 3, 4, 5,};
+
+    private IEnumerable<string> GetStringValues()
+    {
+        yield return "One";
+        yield return "Two";
+        yield return "Three";
+    }
+
+    private IEnumerable<TriDropdownItem<Vector3>> GetVectorValues()
+    {
+        return new TriDropdownList<Vector3>
+        {
+            {"Zero", Vector3.zero},
+            {"One/Forward", Vector3.forward},
+            {"One/Backward", Vector3.back},
+            {"One/Left", Vector3.left},
+            {"One/Right", Vector3.right},
+        };
+    }
+}

Editor.Samples/Decorators/Decorators_DropdownSample.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 69374eab3b684d3babd15136620a9862
+timeCreated: 1656933689

README.md

@@ -10,6 +10,7 @@ _Advanced inspector attributes for Unity_
 - [Attributes](#Attributes)
     - [Misc](#Misc)
     - [Validation](#Validation)
+    - [Decorators](#Decorators)
     - [Styling](#Styling)
     - [Collections](#Collections)
     - [Conditionals](#Conditionals)
@@ -170,6 +171,32 @@ private bool VisibleInEditMode => !Application.isPlaying;
 public GameObject obj;
 ```
 
+### Decorators
+
+#### Dropdown
+
+![Dropdown](https://user-images.githubusercontent.com/26966368/177182904-8bb40579-3dc5-441b-8f6b-3ff3d274f71f.png)
+
+```csharp
+[Dropdown(nameof(intValues))]
+public int intValue = 1;
+
+[Dropdown(nameof(GetVectorValues))]
+public Vector3 vectorValue;
+
+private int[] intValues = {1, 2, 3, 4, 5};
+
+private IEnumerable<TriDropdownItem<Vector3>> GetVectorValues()
+{
+    return new TriDropdownList<Vector3>
+    {
+        {"Zero", Vector3.zero},
+        {"One/Forward", Vector3.forward},
+        {"One/Backward", Vector3.back},
+    };
+}
+```
+
 ### Styling
 
 #### Title

Runtime/Attributes/DropdownAttribute.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Diagnostics;
+
+namespace TriInspector
+{
+    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
+    [Conditional("UNITY_EDITOR")]
+    public sealed class DropdownAttribute : Attribute
+    {
+        public string Values { get; }
+
+        public DropdownAttribute(string values)
+        {
+            Values = values;
+        }
+    }
+}

Runtime/Attributes/DropdownAttribute.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 715d2fca9b1e4330be5d88eddbbdd801
+timeCreated: 1656933469

Runtime/TriDropdownList.cs

@@ -0,0 +1,33 @@
+using System.Collections.Generic;
+
+namespace TriInspector
+{
+    public class TriDropdownList<T> : List<TriDropdownItem<T>>
+    {
+        public void Add(string text, T value)
+        {
+            Add(new TriDropdownItem<T> {Text = text, Value = value,});
+        }
+    }
+
+    public interface ITriDropdownItem
+    {
+        string Text { get; }
+        object Value { get; }
+    }
+
+    public struct TriDropdownItem : ITriDropdownItem
+    {
+        public string Text { get; set; }
+        public object Value { get; set; }
+    }
+
+    public struct TriDropdownItem<T> : ITriDropdownItem
+    {
+        public string Text;
+        public T Value;
+
+        string ITriDropdownItem.Text => Text;
+        object ITriDropdownItem.Value => Value;
+    }
+}

Runtime/TriDropdownList.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: bdeda5f861ce4f359c0a25554ffe70bf
+timeCreated: 1656937692