Seperated DragBar class.

osu.Game/Overlays/DragBar.cs

@@ -0,0 +1,69 @@
+//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.Sprites;
+using osu.Framework.Input;
+
+namespace osu.Game.Overlays
+{
+    public class DragBar : Container
+    {
+        private Box fill;
+
+        public Action<float> SeekRequested;
+        private bool isDragging;
+
+        public DragBar()
+        {
+            RelativeSizeAxes = Axes.X;
+
+            Children = new Drawable[]
+            {
+                fill = new Box()
+                {
+                    Origin = Anchor.CentreLeft,
+                    Anchor = Anchor.CentreLeft,
+                    RelativeSizeAxes = Axes.Both,
+                    Width = 0
+                }
+            };
+        }
+
+        public void UpdatePosition(float position)
+        {
+            if (isDragging) return;
+
+            fill.Width = position;
+        }
+
+        private void seek(InputState state)
+        {
+            float seekLocation = state.Mouse.Position.X / DrawWidth;
+            SeekRequested?.Invoke(seekLocation);
+            fill.Width = seekLocation;
+        }
+
+        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
+        {
+            seek(state);
+            return true;
+        }
+
+        protected override bool OnDrag(InputState state)
+        {
+            seek(state);
+            return true;
+        }
+
+        protected override bool OnDragStart(InputState state) => isDragging = true;
+
+        protected override bool OnDragEnd(InputState state)
+        {
+            isDragging = false;
+            return true;
+        }
+    }
+}

osu.Game/osu.Game.csproj

@@ -63,6 +63,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Overlays\DragBar.cs" />
     <Compile Include="Overlays\MusicController.cs" />
     <Compile Include="Beatmaps\Beatmap.cs" />
     <Compile Include="Beatmaps\Drawable\BeatmapSetHeader.cs" />