Rewrite a lot of Song Select to share logic between panels and consolidate logic inside classes where possible.

osu.Game/Beatmaps/Drawable/BeatmapGroup.cs

@@ -7,19 +7,14 @@ using osu.Framework;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Primitives;
-using osu.Framework.Input;
 using osu.Game.Database;
 using OpenTK;
-using OpenTK.Graphics;
 
 namespace osu.Game.Beatmaps.Drawable
 {
     class BeatmapGroup : Container, IStateful<BeatmapGroupState>
     {
-        private const float collapsedAlpha = 0.5f;
+        public BeatmapPanel SelectedPanel;
-        private const float collapsedWidth = 0.8f;
-
-        private BeatmapPanel selectedPanel;
 
         /// <summary>
         /// Fires when one of our difficulties was selected. Will fire on first expand.
@@ -44,23 +39,16 @@ namespace osu.Game.Beatmaps.Drawable
                         FadeTo(1, 250);
                         difficulties.Show();
 
-                        //todo: header should probably have a state, with this logic moved inside it.
+                        header.State = PanelSelectedState.Selected;
-                        header.Width = 1;
-                        header.GlowRadius = 5;
-                        header.BorderColour = new Color4(header.BorderColour.R, header.BorderColour.G, header.BorderColour.B, 255);
 
-                        if (selectedPanel == null)
+                        if (SelectedPanel == null)
-                            (difficulties.Children.FirstOrDefault() as BeatmapPanel).Selected = true;
+                            ((BeatmapPanel)difficulties.Children.FirstOrDefault()).State = PanelSelectedState.Selected;
-                        SelectionChanged?.Invoke(this, selectedPanel?.Beatmap);
                         break;
                     case BeatmapGroupState.Collapsed:
-                        FadeTo(collapsedAlpha, 250);
+                        FadeTo(0.5f, 250);
-                        difficulties.Hide();
 
-                        //todo: header should probably have a state, with this logic moved inside it.
+                        header.State = PanelSelectedState.NotSelected;
-                        header.Width = collapsedWidth;
+                        difficulties.Hide();
-                        header.GlowRadius = 0;
-                        header.BorderColour = new Color4(header.BorderColour.R, header.BorderColour.G, header.BorderColour.B, 0);
                         break;
                 }
             }
@@ -68,10 +56,12 @@ namespace osu.Game.Beatmaps.Drawable
 
         public BeatmapGroup(BeatmapSetInfo beatmapSet)
         {
-            this.beatmapSet = beatmapSet;
+            this.beatmapSet = beatmapSet;
+
             Alpha = 0;
             AutoSizeAxes = Axes.Y;
-            RelativeSizeAxes = Axes.X;
+            RelativeSizeAxes = Axes.X;
+
             Children = new[]
             {
                 new FlowContainer
@@ -83,8 +73,8 @@ namespace osu.Game.Beatmaps.Drawable
                     {
                         header = new BeatmapSetHeader(beatmapSet)
                         {
+                            GainedSelection = headerGainedSelection,
                             RelativeSizeAxes = Axes.X,
-                            Width = collapsedWidth,
                             Anchor = Anchor.TopRight,
                             Origin = Anchor.TopRight,
                         },
@@ -118,18 +108,21 @@ namespace osu.Game.Beatmaps.Drawable
             State = BeatmapGroupState.Collapsed;
         }
 
-        private void panelGainedSelection(BeatmapPanel panel)
+        private void headerGainedSelection(BeatmapSetHeader panel)
         {
-            if (selectedPanel != null) selectedPanel.Selected = false;
+            State = BeatmapGroupState.Expanded;
-            selectedPanel = panel;
+
-            
+            SelectionChanged?.Invoke(this, SelectedPanel.Beatmap);
-            SelectionChanged?.Invoke(this, panel.Beatmap);
         }
 
-        protected override bool OnClick(InputState state)
+        private void panelGainedSelection(BeatmapPanel panel)
         {
             State = BeatmapGroupState.Expanded;
-            return true;
+
+            if (SelectedPanel != null) SelectedPanel.State = PanelSelectedState.NotSelected;
+            SelectedPanel = panel;
+
+            SelectionChanged?.Invoke(this, panel.Beatmap);
         }
     }
 

osu.Game/Beatmaps/Drawable/BeatmapPanel.cs

@@ -6,7 +6,6 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Primitives;
 using osu.Framework.Graphics.Sprites;
-using osu.Framework.Input;
 using osu.Game.Database;
 using osu.Game.Graphics;
 using osu.Game.Graphics.UserInterface;
@@ -15,42 +14,23 @@ using OpenTK.Graphics;
 
 namespace osu.Game.Beatmaps.Drawable
 {
-    class BeatmapPanel : Container
+    class BeatmapPanel : Panel
     {
         public BeatmapInfo Beatmap;
 
-        public Action<BeatmapPanel> GainedSelection;
+        public Action<BeatmapPanel> GainedSelection;
-        
+
-        private bool selected;
+        protected override void Selected()
-
+        {
-        public bool Selected
+            base.Selected();
-        {
+            GainedSelection?.Invoke(this);
-            get { return selected; }
-            set
-            {
-                if (selected == value)
-                    return;
-                selected = value;
-                BorderColour = new Color4(
-                    BorderColour.R,
-                    BorderColour.G,
-                    BorderColour.B,
-                    selected ? 255 : 0);
-                GlowRadius = selected ? 3 : 0;
-
-                if (selected) GainedSelection?.Invoke(this);
-            }
         }
 
         public BeatmapPanel(BeatmapSetInfo set, BeatmapInfo beatmap)
-        {
+        {
-            Beatmap = beatmap;
+            Beatmap = beatmap;
-            AutoSizeAxes = Axes.Y;
+            Height *= 0.75f;
-            Masking = true;
+
-            CornerRadius = 5;
-            BorderThickness = 2;
-            BorderColour = new Color4(221, 255, 255, 0);
-            GlowColour = new Color4(166, 221, 251, 0.75f); // TODO: Get actual color for this
             Children = new Framework.Graphics.Drawable[]
             {
                 new Box
@@ -87,8 +67,7 @@ namespace osu.Game.Beatmaps.Drawable
                                         },
                                         new SpriteText
                                         {
-                                            Text = string.Format(" mapped by {0}",
+                                            Text = $" mapped by {(beatmap.Metadata ?? set.Metadata).Author}",
-                                                (beatmap.Metadata ?? set.Metadata).Author),
                                             TextSize = 16,
                                         },
                                     }
@@ -99,12 +78,6 @@ namespace osu.Game.Beatmaps.Drawable
                     }
                 }
             };
-        }
+        }
-        
-        protected override bool OnClick(InputState state)
-        {
-            Selected = true;
-            return true;
-        }
     }
 }

osu.Game/Beatmaps/Drawable/BeatmapSetHeader.cs

@@ -1,6 +1,7 @@
 //Copyright (c) 2007-2016 ppy Pty Ltd <contact@ppy.sh>.
 //Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Primitives;
@@ -12,35 +13,42 @@ using OpenTK.Graphics;
 
 namespace osu.Game.Beatmaps.Drawable
 {
-    class BeatmapSetHeader : Container
+    class BeatmapSetHeader : Panel
     {
+        public Action<BeatmapSetHeader> GainedSelection;
+
+        protected override void Selected()
+        {
+            base.Selected();
+
+            Width = 1;
+            GainedSelection?.Invoke(this);
+        }
+
+        protected override void Deselected()
+        {
+            base.Deselected();
+            Width = 0.8f;
+        }
+
         public BeatmapSetHeader(BeatmapSetInfo beatmapSet)
         {
-            AutoSizeAxes = Axes.Y;
-            Masking = true;
-            CornerRadius = 5;
-            BorderThickness = 2;
-            BorderColour = new Color4(221, 255, 255, 0);
-            GlowColour = new Color4(166, 221, 251, 0.5f); // TODO: Get actual color for this
             Children = new Framework.Graphics.Drawable[]
             {
                 new Box
                 {
                     Colour = new Color4(85, 85, 85, 255),
                     RelativeSizeAxes = Axes.Both,
-                    Size = Vector2.One,
                 },
                 new Container
                 {
                     RelativeSizeAxes = Axes.Both,
-                    Size = Vector2.One,
                     Children = new Framework.Graphics.Drawable[]
                     {
                         new Box // TODO: Gradient
                         {
                             Colour = new Color4(0, 0, 0, 100),
                             RelativeSizeAxes = Axes.Both,
-                            Size = Vector2.One,
                         }
                     }
                 },
@@ -48,7 +56,7 @@ namespace osu.Game.Beatmaps.Drawable
                 {
                     Direction = FlowDirection.VerticalOnly,
                     Spacing = new Vector2(0, 2),
-                    Padding = new MarginPadding { Top = 3, Left = 20, Right = 20, Bottom = 3 },
+                    Padding = new MarginPadding { Top = 10, Left = 15, Right = 10, Bottom = 10 },
                     AutoSizeAxes = Axes.Both,
                     Children = new[]
                     {
@@ -75,6 +83,8 @@ namespace osu.Game.Beatmaps.Drawable
                     }
                 }
             };
+
+            Deselected();
         }
     }
 }

osu.Game/Beatmaps/Drawable/Panel.cs

@@ -0,0 +1,81 @@
+//Copyright (c) 2007-2016 ppy Pty Ltd <contact@ppy.sh>.
+//Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using osu.Framework;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input;
+using OpenTK.Graphics;
+
+namespace osu.Game.Beatmaps.Drawable
+{
+    class Panel : Container, IStateful<PanelSelectedState>
+    {
+        public Panel()
+        {
+            Height = 80;
+
+            Masking = true;
+            CornerRadius = 10;
+            BorderColour = new Color4(221, 255, 255, 0);
+            GlowColour = new Color4(102, 204, 255, 100);
+
+            RelativeSizeAxes = Axes.X;
+        }
+
+        private PanelSelectedState state;
+
+        public PanelSelectedState State
+        {
+            get { return state; }
+
+            set
+            {
+                if (state == value) return;
+
+                state = value;
+
+                switch (state)
+                {
+                    case PanelSelectedState.NotSelected:
+                        Deselected();
+                        break;
+                    case PanelSelectedState.Selected:
+                        Selected();
+                        break;
+                }
+            }
+        }
+
+        protected virtual void Selected()
+        {
+            BorderColour = new Color4(BorderColour.R, BorderColour.G, BorderColour.B, 255);
+            GlowRadius = 10;
+            BorderThickness = 2.5f;
+        }
+
+        protected virtual void Deselected()
+        {
+            BorderColour = new Color4(BorderColour.R, BorderColour.G, BorderColour.B, 0);
+            GlowRadius = 0;
+            BorderThickness = 0;
+        }
+
+        protected override bool OnClick(InputState state)
+        {
+            State = PanelSelectedState.Selected;
+            return true;
+        }
+    }
+
+    enum PanelSelectedState
+    {
+        NotSelected,
+        Selected
+    }
+}

osu.Game/GameModes/Play/PlaySongSelect.cs

@@ -26,7 +26,6 @@ namespace osu.Game.GameModes.Play
         private Bindable<PlayMode> playMode;
         private BeatmapDatabase database;
         private BeatmapGroup selectedBeatmapGroup;
-        private BeatmapInfo selectedBeatmap;
         // TODO: use currently selected track as bg
         protected override BackgroundMode CreateBackground() => new BackgroundModeCustom(@"Backgrounds/bg4");
         private ScrollContainer scrollContainer;
@@ -106,7 +105,7 @@ namespace osu.Game.GameModes.Play
                             Width = 100,
                             Text = "Play",
                             Colour = new Color4(238, 51, 153, 255),
-                            Action = () => Push(new Player { BeatmapInfo = selectedBeatmap }),
+                            Action = () => Push(new Player { BeatmapInfo = selectedBeatmapGroup.SelectedPanel.Beatmap }),
                         },
                     }
                 }
@@ -129,7 +128,7 @@ namespace osu.Game.GameModes.Play
             if (database == null)
                 database = (game as OsuGameBase).Beatmaps;
 
-            database.BeatmapSetAdded += s => Scheduler.Add(() => addBeatmapSet(s));
+            database.BeatmapSetAdded += s => Schedule(() => addBeatmapSet(s));
 
             Task.Factory.StartNew(addBeatmapSets);
         }
@@ -154,7 +153,6 @@ namespace osu.Game.GameModes.Play
                 selectedBeatmapGroup.State = BeatmapGroupState.Collapsed;
 
             selectedBeatmapGroup = group;
-            selectedBeatmap = beatmap;
         }
 
         private void addBeatmapSet(BeatmapSetInfo beatmapSet)
@@ -167,9 +165,7 @@ namespace osu.Game.GameModes.Play
                 var group = new BeatmapGroup(beatmapSet) { SelectionChanged = selectBeatmap };
                 setList.Add(group);
                 if (setList.Children.Count() == 1)
-                {
                     group.State = BeatmapGroupState.Expanded;
-                }
             });
         }
 

osu.Game/osu.Game.csproj

@@ -66,6 +66,7 @@
     <Compile Include="Beatmaps\Beatmap.cs" />
     <Compile Include="Beatmaps\Drawable\BeatmapSetHeader.cs" />
     <Compile Include="Beatmaps\Drawable\DifficultyIcon.cs" />
+    <Compile Include="Beatmaps\Drawable\Panel.cs" />
     <Compile Include="Beatmaps\Objects\Catch\CatchConverter.cs" />
     <Compile Include="Beatmaps\Objects\Catch\Drawable\DrawableFruit.cs" />
     <Compile Include="Beatmaps\Objects\DrawableHitObject.cs" />