Add simple listing of currently playing users

osu.Game/Overlays/Dashboard/CurrentlyPlayingDisplay.cs

@@ -0,0 +1,95 @@
+// 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.Collections.Specialized;
+using System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Screens;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using osu.Game.Online.Spectator;
+using osu.Game.Screens.Play;
+using osu.Game.Users;
+using osuTK;
+
+namespace osu.Game.Overlays.Dashboard
+{
+    internal class CurrentlyPlayingDisplay : CompositeDrawable
+    {
+        private IBindableList<int> playingUsers;
+
+        private FillFlowContainer<UserPanel> userFlow;
+
+        [Resolved]
+        private SpectatorStreamingClient spectatorStreaming { get; set; }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            RelativeSizeAxes = Axes.X;
+            AutoSizeAxes = Axes.Y;
+
+            InternalChild = userFlow = new FillFlowContainer<UserPanel>
+            {
+                RelativeSizeAxes = Axes.X,
+                AutoSizeAxes = Axes.Y,
+                Spacing = new Vector2(10),
+            };
+        }
+
+        [Resolved]
+        private IAPIProvider api { get; set; }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            playingUsers = spectatorStreaming.PlayingUsers.GetBoundCopy();
+            playingUsers.BindCollectionChanged((sender, e) => Schedule(() =>
+            {
+                switch (e.Action)
+                {
+                    case NotifyCollectionChangedAction.Add:
+                        foreach (var u in e.NewItems.OfType<int>())
+                        {
+                            var request = new GetUserRequest(u);
+                            request.Success += user => Schedule(() =>
+                            {
+                                if (playingUsers.Contains((int)user.Id))
+                                    userFlow.Add(createUserPanel(user));
+                            });
+                            api.Queue(request);
+                        }
+
+                        break;
+
+                    case NotifyCollectionChangedAction.Remove:
+                        foreach (var u in e.OldItems.OfType<int>())
+                            userFlow.FirstOrDefault(card => card.User.Id == u)?.Expire();
+                        break;
+
+                    case NotifyCollectionChangedAction.Reset:
+                        userFlow.Clear();
+                        break;
+                }
+            }), true);
+        }
+
+        [Resolved]
+        private OsuGame game { get; set; }
+
+        private UserPanel createUserPanel(User user)
+        {
+            return new UserGridPanel(user).With(panel =>
+            {
+                panel.Anchor = Anchor.TopCentre;
+                panel.Origin = Anchor.TopCentre;
+                panel.Width = 290;
+                panel.Action = () => game.PerformFromScreen(s => s.Push(new Spectator(user)));
+            });
+        }
+    }
+}

osu.Game/Overlays/Dashboard/DashboardOverlayHeader.cs

@@ -1,6 +1,8 @@
 // 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.ComponentModel;
+
 namespace osu.Game.Overlays.Dashboard
 {
     public class DashboardOverlayHeader : TabControlOverlayHeader<DashboardOverlayTabs>
@@ -20,6 +22,9 @@ namespace osu.Game.Overlays.Dashboard
 
     public enum DashboardOverlayTabs
     {
-        Friends
+        Friends,
+
+        [Description("Currently Playing")]
+        CurrentlyPlaying
     }
 }

osu.Game/Overlays/DashboardOverlay.cs

@@ -130,6 +130,10 @@ namespace osu.Game.Overlays
                     loadDisplay(new FriendDisplay());
                     break;
 
+                case DashboardOverlayTabs.CurrentlyPlaying:
+                    loadDisplay(new CurrentlyPlayingDisplay());
+                    break;
+
                 default:
                     throw new NotImplementedException($"Display for {tab.NewValue} tab is not implemented");
             }