Add ScreenBreadcrumbControl.

osu.Game.Tests/Visual/TestCaseScreenBreadcrumbs.cs

@@ -0,0 +1,108 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Screens;
+using OpenTK;
+
+namespace osu.Game.Tests.Visual
+{
+    [TestFixture]
+    public class TestCaseScreenBreadcrumbs : OsuTestCase
+    {
+        private readonly ScreenBreadcrumbControl<TestScreen> breadcrumbs;
+
+        public TestCaseScreenBreadcrumbs()
+        {
+            TestScreen startScreen;
+            OsuSpriteText titleText;
+
+            Children = new Drawable[]
+            {
+                new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.X,
+                    AutoSizeAxes = Axes.Y,
+                    Direction = FillDirection.Vertical,
+                    Spacing = new Vector2(10),
+                    Children = new Drawable[]
+                    {
+                        breadcrumbs = new ScreenBreadcrumbControl<TestScreen>
+                        {
+                            RelativeSizeAxes = Axes.X,
+                        },
+                        titleText = new OsuSpriteText(),
+                    },
+                },
+                startScreen = new TestScreenOne(),
+            };
+
+            breadcrumbs.OnScreenChanged += s => titleText.Text = $"Changed to {s.ToString()}";
+            breadcrumbs.CurrentScreen = startScreen;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            breadcrumbs.StripColour = colours.Blue;
+        }
+
+        private abstract class TestScreen : OsuScreen
+        {
+            protected abstract string Title { get; }
+            protected abstract string NextTitle { get; }
+            protected abstract TestScreen CreateNextScreen();
+
+            public override string ToString() => Title;
+
+            protected TestScreen()
+            {
+                Child = new FillFlowContainer
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    AutoSizeAxes = Axes.Both,
+                    Direction = FillDirection.Vertical,
+                    Spacing = new Vector2(10),
+                    Children = new Drawable[]
+                    {
+                        new OsuSpriteText
+                        {
+                            Anchor = Anchor.TopCentre,
+                            Origin = Anchor.TopCentre,
+                            Text = Title,
+                        },
+                        new TriangleButton
+                        {
+                            Anchor = Anchor.TopCentre,
+                            Origin = Anchor.TopCentre,
+                            Width = 100,
+                            Text = $"Push {NextTitle}",
+                            Action = () => Push(CreateNextScreen()),
+                        },
+                    },
+                };
+            }
+        }
+
+        private class TestScreenOne : TestScreen
+        {
+            protected override string Title => @"Screen One";
+            protected override string NextTitle => @"Two";
+            protected override TestScreen CreateNextScreen() => new TestScreenTwo();
+        }
+
+        private class TestScreenTwo : TestScreen
+        {
+            protected override string Title => @"Screen Two";
+            protected override string NextTitle => @"One";
+            protected override TestScreen CreateNextScreen() => new TestScreenOne();
+        }
+    }
+}

osu.Game/Graphics/UserInterface/ScreenBreadcrumbControl.cs

@@ -0,0 +1,78 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Linq;
+using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Framework.Screens;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public class ScreenBreadcrumbControl : ScreenBreadcrumbControl<Screen>
+    {
+    }
+
+    public class ScreenBreadcrumbControl<T> : BreadcrumbControl<T> where T : Screen
+    {
+        private T currentScreen;
+        public T CurrentScreen
+        {
+            get { return currentScreen; }
+            set
+            {
+                if (value == currentScreen) return;
+
+                if (CurrentScreen != null)
+                {
+                    CurrentScreen.Exited -= onExited;
+                    CurrentScreen.ModePushed -= onPushed;
+                }
+                else
+                {
+                    // this is the first screen in the stack, so call the initial onPushed
+                    currentScreen = value;
+                    onPushed(CurrentScreen);
+                }
+
+                currentScreen = value;
+
+                if (CurrentScreen != null)
+                {
+                    CurrentScreen.Exited += onExited;
+                    CurrentScreen.ModePushed += onPushed;
+                    Current.Value = CurrentScreen;
+                    OnScreenChanged?.Invoke(CurrentScreen);
+                }
+            }
+        }
+
+        public event Action<T> OnScreenChanged;
+
+        public ScreenBreadcrumbControl()
+        {
+            Current.ValueChanged += s =>
+            {
+                if (s != CurrentScreen)
+                {
+                    CurrentScreen = s;
+                    s.MakeCurrent();
+                }
+            };
+        }
+
+        private void onExited(Screen screen)
+        {
+            CurrentScreen = screen as T;
+        }
+
+        private void onPushed(Screen screen)
+        {
+            var newScreen = screen as T;
+
+            Items.ToList().SkipWhile(i => i != Current.Value).Skip(1).ForEach(RemoveItem);
+            AddItem(newScreen);
+
+            CurrentScreen = newScreen;
+        }
+    }
+}