added radio group buttons

MLEM.Ui/Elements/RadioGroupButton.cs

@@ -0,0 +1,66 @@
+using Microsoft.Xna.Framework;
+using MLEM.Ui.Style;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace MLEM.Ui.Elements {
+    /// <summary>
+    /// A radio button element to use inside of a <see cref="UiSystem"/>.
+    /// A radio button is a variation of a <see cref="Checkbox"/> that causes all other radio buttons in the same <see cref="RadioGroup"/> to be deselected upon selection.
+    /// </summary>
+    public class RadioGroupButton:Checkbox {
+
+        /// <summary>
+        /// The group that this radio button has.
+        /// All other radio buttons in the same <see cref="RadioGroup"/> that have the same group will be deselected when this radio button is selected.
+        /// </summary>
+        public RadioGroup Group;
+
+        /// <summary>
+        /// Creates a new radio button with the given settings
+        /// </summary>
+        /// <param name="anchor">The radio button's anchor</param>
+        /// <param name="size">The radio button's size</param>
+        /// <param name="label">The label to display next to the radio button</param>
+        /// <param name="defaultChecked">If the radio button should be checked by default</param>
+        /// <param name="group">The group that the radio button has</param>
+        public RadioGroupButton(Anchor anchor, Vector2 size, string label, bool defaultChecked = false, RadioGroup? group = null) :
+            base(anchor, size, label, defaultChecked) {
+            this.Group = group;
+
+            // don't += because we want to override the checking/unchecking behavior of Checkbox
+            this.OnPressed = element => {
+                this.Checked = true;
+                this.Root.Element.AndChildren(e => {
+                    group.Selection = this;
+                });
+            };
+        }
+
+        /// <inheritdoc />
+        protected override void InitStyle(UiStyle style) {
+            base.InitStyle(style);
+            this.Texture = this.Texture.OrStyle(style.RadioTexture);
+            this.HoveredTexture = this.HoveredTexture.OrStyle(style.RadioHoveredTexture);
+            this.HoveredColor = this.HoveredColor.OrStyle(style.RadioHoveredColor);
+            this.Checkmark = this.Checkmark.OrStyle(style.RadioCheckmark);
+        }
+    }
+    /// <summary>
+    /// A group of radio group buttons
+    /// </summary>
+    public class RadioGroup {
+        private RadioGroupButton? selection;
+        public RadioGroupButton? Selection{ get => selection; set {
+            if (selection != null) this.selection.Checked = false;
+            selection = value;
+            if(selection != null) {
+                this.selection.Group = this;
+                this.selection.Checked = true;
+            }
+        }}
+    }
+}