Implement "form" dropdown control

osu.Game.Tests/Visual/UserInterface/TestSceneFormControls.cs

@@ -5,6 +5,7 @@
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Cursor;
+using osu.Game.Beatmaps;
 using osu.Game.Graphics.Cursor;
 using osu.Game.Graphics.UserInterfaceV2;
 using osu.Game.Localisation;
@@ -94,6 +95,11 @@ public TestSceneFormControls()
                             Instantaneous = false,
                             TabbableContentContainer = this,
                         },
+                        new FormEnumDropdown<CountdownType>
+                        {
+                            Caption = EditorSetupStrings.EnableCountdown,
+                            HintText = EditorSetupStrings.CountdownDescription,
+                        },
                     },
                 },
             }

osu.Game/Graphics/UserInterfaceV2/FormDropdown.cs

@@ -0,0 +1,251 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Framework.Allocation;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Colour;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Input.Events;
+using osu.Framework.Localisation;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Overlays;
+using osuTK;
+
+namespace osu.Game.Graphics.UserInterfaceV2
+{
+    public partial class FormDropdown<T> : OsuDropdown<T>
+    {
+        /// <summary>
+        /// Caption describing this slider bar, displayed on top of the controls.
+        /// </summary>
+        public LocalisableString Caption { get; init; }
+
+        /// <summary>
+        /// Hint text containing an extended description of this slider bar, displayed in a tooltip when hovering the caption.
+        /// </summary>
+        public LocalisableString HintText { get; init; }
+
+        private FormDropdownHeader header = null!;
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            RelativeSizeAxes = Axes.X;
+
+            header.Caption = Caption;
+            header.HintText = HintText;
+        }
+
+        protected override DropdownHeader CreateHeader() => header = new FormDropdownHeader
+        {
+            Dropdown = this,
+        };
+
+        protected override DropdownMenu CreateMenu() => new FormDropdownMenu();
+
+        private partial class FormDropdownHeader : DropdownHeader
+        {
+            public FormDropdown<T> Dropdown { get; set; } = null!;
+
+            protected override DropdownSearchBar CreateSearchBar() => SearchBar = new FormDropdownSearchBar();
+
+            private LocalisableString captionText;
+            private LocalisableString hintText;
+            private LocalisableString labelText;
+
+            public LocalisableString Caption
+            {
+                get => captionText;
+                set
+                {
+                    captionText = value;
+
+                    if (caption.IsNotNull())
+                        caption.Caption = value;
+                }
+            }
+
+            public LocalisableString HintText
+            {
+                get => hintText;
+                set
+                {
+                    hintText = value;
+
+                    if (caption.IsNotNull())
+                        caption.TooltipText = value;
+                }
+            }
+
+            protected override LocalisableString Label
+            {
+                get => labelText;
+                set
+                {
+                    labelText = value;
+
+                    if (label.IsNotNull())
+                        label.Text = labelText;
+                }
+            }
+
+            protected new FormDropdownSearchBar SearchBar { get; set; } = null!;
+
+            private FormFieldCaption caption = null!;
+            private OsuSpriteText label = null!;
+            private SpriteIcon chevron = null!;
+
+            [Resolved]
+            private OverlayColourProvider colourProvider { get; set; } = null!;
+
+            [BackgroundDependencyLoader]
+            private void load()
+            {
+                RelativeSizeAxes = Axes.X;
+                AutoSizeAxes = Axes.None;
+                Height = 50;
+
+                Masking = true;
+                CornerRadius = 5;
+
+                Foreground.AutoSizeAxes = Axes.None;
+                Foreground.RelativeSizeAxes = Axes.Both;
+                Foreground.Padding = new MarginPadding(9);
+                Foreground.Children = new Drawable[]
+                {
+                    caption = new FormFieldCaption
+                    {
+                        Anchor = Anchor.TopLeft,
+                        Origin = Anchor.TopLeft,
+                        Caption = Caption,
+                        TooltipText = HintText,
+                    },
+                    label = new OsuSpriteText
+                    {
+                        RelativeSizeAxes = Axes.X,
+                        Anchor = Anchor.BottomLeft,
+                        Origin = Anchor.BottomLeft,
+                    },
+                    chevron = new SpriteIcon
+                    {
+                        Icon = FontAwesome.Solid.ChevronDown,
+                        Anchor = Anchor.CentreRight,
+                        Origin = Anchor.CentreRight,
+                        Size = new Vector2(16),
+                    },
+                };
+
+                AddInternal(new HoverClickSounds());
+            }
+
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+
+                Dropdown.Current.BindDisabledChanged(_ => updateState());
+                SearchBar.SearchTerm.BindValueChanged(_ => updateState(), true);
+                Dropdown.Menu.StateChanged += _ =>
+                {
+                    updateState();
+                    updateChevron();
+                };
+                SearchBar.TextBox.OnCommit += (_, _) =>
+                {
+                    Background.FlashColour(ColourInfo.GradientVertical(colourProvider.Background5, colourProvider.Dark2), 800, Easing.OutQuint);
+                };
+            }
+
+            protected override bool OnHover(HoverEvent e)
+            {
+                updateState();
+                return true;
+            }
+
+            protected override void OnHoverLost(HoverLostEvent e)
+            {
+                base.OnHoverLost(e);
+                updateState();
+            }
+
+            private void updateState()
+            {
+                label.Alpha = string.IsNullOrEmpty(SearchBar.SearchTerm.Value) ? 1 : 0;
+
+                caption.Colour = Dropdown.Current.Disabled ? colourProvider.Foreground1 : colourProvider.Content2;
+                label.Colour = Dropdown.Current.Disabled ? colourProvider.Foreground1 : colourProvider.Content1;
+                chevron.Colour = Dropdown.Current.Disabled ? colourProvider.Foreground1 : colourProvider.Content1;
+                DisabledColour = Colour4.White;
+
+                bool dropdownOpen = Dropdown.Menu.State == MenuState.Open;
+
+                if (!Dropdown.Current.Disabled)
+                {
+                    BorderThickness = IsHovered || dropdownOpen ? 2 : 0;
+                    BorderColour = dropdownOpen ? colourProvider.Highlight1 : colourProvider.Light4;
+
+                    if (dropdownOpen)
+                        Background.Colour = ColourInfo.GradientVertical(colourProvider.Background5, colourProvider.Dark3);
+                    else if (IsHovered)
+                        Background.Colour = ColourInfo.GradientVertical(colourProvider.Background5, colourProvider.Dark4);
+                    else
+                        Background.Colour = colourProvider.Background5;
+                }
+                else
+                {
+                    Background.Colour = colourProvider.Background4;
+                }
+            }
+
+            private void updateChevron()
+            {
+                bool open = Dropdown.Menu.State == MenuState.Open;
+                chevron.ScaleTo(open ? new Vector2(1f, -1f) : Vector2.One, 300, Easing.OutQuint);
+            }
+        }
+
+        private partial class FormDropdownSearchBar : DropdownSearchBar
+        {
+            public FormTextBox.InnerTextBox TextBox { get; private set; } = null!;
+
+            protected override void PopIn() => this.FadeIn();
+            protected override void PopOut() => this.FadeOut();
+
+            protected override TextBox CreateTextBox() => TextBox = new FormTextBox.InnerTextBox();
+
+            [BackgroundDependencyLoader]
+            private void load()
+            {
+                TextBox.Anchor = Anchor.BottomLeft;
+                TextBox.Origin = Anchor.BottomLeft;
+                TextBox.RelativeSizeAxes = Axes.X;
+                TextBox.Margin = new MarginPadding(9);
+            }
+        }
+
+        private partial class FormDropdownMenu : OsuDropdownMenu
+        {
+            [BackgroundDependencyLoader]
+            private void load(OverlayColourProvider colourProvider)
+            {
+                ItemsContainer.Padding = new MarginPadding(9);
+                Margin = new MarginPadding { Top = 5 };
+
+                MaskingContainer.BorderThickness = 2;
+                MaskingContainer.BorderColour = colourProvider.Highlight1;
+            }
+        }
+    }
+
+    public partial class FormEnumDropdown<T> : FormDropdown<T>
+        where T : struct, Enum
+    {
+        public FormEnumDropdown()
+        {
+            Items = Enum.GetValues<T>();
+        }
+    }
+}