Move back button to OsuGame

osu.Game/OsuGame.cs

@@ -29,6 +29,7 @@ using osu.Framework.Threading;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.UserInterface;
 using osu.Game.Input;
 using osu.Game.Overlays.Notifications;
 using osu.Game.Screens.Play;
@@ -82,6 +83,7 @@ namespace osu.Game
         private OsuScreenStack screenStack;
         private VolumeOverlay volume;
         private OsuLogo osuLogo;
+        private BackButton backButton;
 
         private MainMenu menuScreen;
         private Intro introScreen;
@@ -402,6 +404,13 @@ namespace osu.Game
                         logoContainer = new Container { RelativeSizeAxes = Axes.Both },
                     }
                 },
+                backButton = new BackButton
+                {
+                    Anchor = Anchor.BottomLeft,
+                    Origin = Anchor.BottomLeft,
+                    Alpha = 0,
+                    Action = screenStack.Exit
+                },
                 overlayContent = new Container { RelativeSizeAxes = Axes.Both },
                 rightFloatingOverlayContent = new Container { RelativeSizeAxes = Axes.Both },
                 leftFloatingOverlayContent = new Container { RelativeSizeAxes = Axes.Both },
@@ -795,6 +804,8 @@ namespace osu.Game
                     CloseAllOverlays();
                 else
                     Toolbar.Show();
+
+                backButton.Alpha = newOsuScreen.ShowBackButton ? 1 : 0;
             }
         }
 

osu.Game/Screens/Edit/Editor.cs

@@ -32,6 +32,8 @@ namespace osu.Game.Screens.Edit
     {
         protected override BackgroundScreen CreateBackground() => new BackgroundScreenCustom(@"Backgrounds/bg4");
 
+        public override bool AllowBackButton => false;
+
         public override bool HideOverlaysOnEnter => true;
 
         public override bool DisallowExternalBeatmapRulesetChanges => true;

osu.Game/Screens/IOsuScreen.cs

@@ -17,6 +17,16 @@ namespace osu.Game.Screens
         /// </summary>
         bool DisallowExternalBeatmapRulesetChanges { get; }
 
+        /// <summary>
+        /// Whether a visual display for the back button should be shown.
+        /// </summary>
+        bool ShowBackButton { get; }
+
+        /// <summary>
+        /// Whether the user can exit this this <see cref="IOsuScreen"/> by pressing the back button.
+        /// </summary>
+        bool AllowBackButton { get; }
+
         /// <summary>
         /// Whether a top-level component should be allowed to exit the current screen to, for example,
         /// complete an import. Note that this can be overridden by a user if they specifically request.

osu.Game/Screens/Loader.cs

@@ -23,7 +23,7 @@ namespace osu.Game.Screens
 
         public override bool CursorVisible => false;
 
-        protected override bool AllowBackButton => false;
+        public override bool AllowBackButton => false;
 
         public Loader()
         {

osu.Game/Screens/Menu/Intro.cs

@@ -32,6 +32,8 @@ namespace osu.Game.Screens.Menu
         private SampleChannel welcome;
         private SampleChannel seeya;
 
+        public override bool AllowBackButton => false;
+
         public override bool HideOverlaysOnEnter => true;
         public override OverlayActivation InitialOverlayActivationMode => OverlayActivation.Disabled;
 

osu.Game/Screens/Menu/MainMenu.cs

@@ -27,7 +27,9 @@ namespace osu.Game.Screens.Menu
 
         public override bool HideOverlaysOnEnter => buttons == null || buttons.State == ButtonSystemState.Initial;
 
-        protected override bool AllowBackButton => buttons.State != ButtonSystemState.Initial && host.CanExit;
+        public override bool ShowBackButton => false;
+
+        public override bool AllowBackButton => buttons.State != ButtonSystemState.Initial && host.CanExit;
 
         public override bool AllowExternalScreenChange => true;
 

osu.Game/Screens/OsuScreen.cs

@@ -36,7 +36,9 @@ namespace osu.Game.Screens
 
         public string Description => Title;
 
-        protected virtual bool AllowBackButton => true;
+        public virtual bool ShowBackButton => AllowBackButton;
+
+        public virtual bool AllowBackButton => true;
 
         public virtual bool AllowExternalScreenChange => false;
 

osu.Game/Screens/Play/Player.cs

@@ -33,7 +33,7 @@ namespace osu.Game.Screens.Play
 {
     public class Player : ScreenWithBeatmapBackground
     {
-        protected override bool AllowBackButton => false; // handled by HoldForMenuButton
+        public override bool AllowBackButton => false; // handled by HoldForMenuButton
 
         protected override UserActivity InitialActivity => new UserActivity.SoloGame(Beatmap.Value.BeatmapInfo, Ruleset.Value);
 

osu.Game/Screens/Ranking/Results.cs

@@ -16,7 +16,6 @@ using osu.Game.Screens.Backgrounds;
 using osuTK;
 using osuTK.Graphics;
 using osu.Game.Graphics;
-using osu.Game.Graphics.UserInterface;
 using osu.Framework.Graphics.Shapes;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Scoring;
@@ -254,13 +253,7 @@ namespace osu.Game.Screens.Ranking
                             }
                         }
                     }
-                },
+                }
-                new BackButton
-                {
-                    Anchor = Anchor.BottomLeft,
-                    Origin = Anchor.BottomLeft,
-                    Action = this.Exit
-                },
             };
 
             foreach (var t in CreateResultPages())

osu.Game/Screens/ScreenWhiteBox.cs

@@ -20,8 +20,6 @@ namespace osu.Game.Screens
 {
     public class ScreenWhiteBox : OsuScreen
     {
-        private readonly BackButton popButton;
-
         private const double transition_time = 1000;
 
         protected virtual IEnumerable<Type> PossibleChildren => null;
@@ -35,10 +33,6 @@ namespace osu.Game.Screens
         {
             base.OnEntering(last);
 
-            //only show the pop button if we are entered form another screen.
-            if (last != null)
-                popButton.Alpha = 1;
-
             Alpha = 0;
             textContainer.Position = new Vector2(DrawSize.X / 16, 0);
 
@@ -144,13 +138,6 @@ namespace osu.Game.Screens
                         },
                     }
                 },
-                popButton = new BackButton
-                {
-                    Anchor = Anchor.BottomLeft,
-                    Origin = Anchor.BottomLeft,
-                    Alpha = 0,
-                    Action = this.Exit
-                },
                 childModeButtons = new FillFlowContainer
                 {
                     Direction = FillDirection.Vertical,

osu.Game/Screens/Select/Footer.cs

@@ -1,7 +1,6 @@
 // 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 System.Collections.Generic;
 using System.Linq;
 using osuTK;
@@ -25,8 +24,6 @@ namespace osu.Game.Screens.Select
 
         private const float padding = 80;
 
-        public Action OnBack;
-
         private readonly FillFlowContainer<FooterButton> buttons;
 
         private readonly List<OverlayContainer> overlays = new List<OverlayContainer>();
@@ -83,12 +80,6 @@ namespace osu.Game.Screens.Select
                     Height = 3,
                     Position = new Vector2(0, -3),
                 },
-                new BackButton
-                {
-                    Anchor = Anchor.BottomLeft,
-                    Origin = Anchor.BottomLeft,
-                    Action = () => OnBack?.Invoke()
-                },
                 new FillFlowContainer
                 {
                     Anchor = Anchor.BottomLeft,

osu.Game/Screens/Select/SongSelect.cs

@@ -186,23 +186,16 @@ namespace osu.Game.Screens.Select
 
             if (ShowFooter)
             {
-                AddInternal(FooterPanels = new Container
+                AddRangeInternal(new[]
+                {
+                    FooterPanels = new Container
                     {
                         Anchor = Anchor.BottomLeft,
                         Origin = Anchor.BottomLeft,
                         RelativeSizeAxes = Axes.X,
                         AutoSizeAxes = Axes.Y,
-                    Margin = new MarginPadding
+                        Margin = new MarginPadding { Bottom = Footer.HEIGHT },
-                    {
+                        Children = new Drawable[]
-                        Bottom = Footer.HEIGHT,
-                    },
-                });
-                AddInternal(Footer = new Footer
-                {
-                    OnBack = ExitFromBack,
-                });
-
-                FooterPanels.AddRange(new Drawable[]
                         {
                             BeatmapOptions = new BeatmapOptionsOverlay(),
                             ModSelect = new ModSelectOverlay
@@ -211,6 +204,9 @@ namespace osu.Game.Screens.Select
                                 Origin = Anchor.BottomCentre,
                                 Anchor = Anchor.BottomCentre,
                             }
+                        }
+                    },
+                    Footer = new Footer()
                 });
             }