Merge pull request #5044 from Susko3/android-back

Add a way to exit/minimize the app on Android when back is pressed

osu.Framework.Android/AndroidGameHost.cs

@@ -44,6 +44,8 @@ protected override void SetupConfig(IDictionary<FrameworkSetting, object> defaul
 
         public override bool CanExit => false;
 
+        public override bool CanSuspendToBackground => true;
+
         public override bool OnScreenKeyboardOverlapsGameWindow => true;
 
         protected override TextInputSource CreateTextInput() => new AndroidTextInput(gameView);
@@ -89,5 +91,10 @@ public override IResourceStore<TextureUpload> CreateTextureLoaderStore(IResource
 
         public override VideoDecoder CreateVideoDecoder(Stream stream)
             => new AndroidVideoDecoder(stream);
+
+        public override bool SuspendToBackground()
+        {
+            return gameView.Activity.MoveTaskToBack(true);
+        }
     }
 }

osu.Framework.Tests.Android/TestGameActivity.cs

@@ -2,8 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using Android.App;
-using Android.OS;
-using Android.Views;
 using osu.Framework.Android;
 
 namespace osu.Framework.Tests.Android

osu.Framework/Platform/GameHost.cs

@@ -104,8 +104,17 @@ public abstract class GameHost : IIpcHost, IDisposable
         /// <summary>
         /// Whether this host can exit (mobile platforms, for instance, do not support exiting the app).
         /// </summary>
+        /// <remarks>Also see <see cref="CanSuspendToBackground"/>.</remarks>
         public virtual bool CanExit => true;
 
+        /// <summary>
+        /// Whether this host can suspend and minimize to background.
+        /// </summary>
+        /// <remarks>
+        /// This and <see cref="SuspendToBackground"/> are an alternative way to exit on hosts that have <see cref="CanExit"/> <c>false</c>.
+        /// </remarks>
+        public virtual bool CanSuspendToBackground => false;
+
         /// <summary>
         /// Whether memory constraints should be considered before performance concerns.
         /// </summary>
@@ -583,12 +592,26 @@ private set
         /// <summary>
         /// Schedules the game to exit in the next frame.
         /// </summary>
+        /// <remarks>Consider using <see cref="SuspendToBackground"/> on mobile platforms that can't exit normally.</remarks>
         public void Exit()
         {
             if (CanExit)
                 PerformExit(false);
         }
 
+        /// <summary>
+        /// Suspends and minimizes the game to background.
+        /// </summary>
+        /// <remarks>
+        /// This is provided as an alternative to <see cref="Exit"/> on hosts that can't exit (see <see cref="CanExit"/>).
+        /// Should only be called if <see cref="CanSuspendToBackground"/> is <c>true</c>.
+        /// </remarks>
+        /// <returns><c>true</c> if the game was successfully suspended and minimized.</returns>
+        public virtual bool SuspendToBackground()
+        {
+            return false;
+        }
+
         /// <summary>
         /// Schedules the game to exit in the next frame (or immediately if <paramref name="immediately"/> is true).
         /// </summary>

osu.Framework/Testing/TestBrowser.cs

@@ -129,7 +129,10 @@ private void load(Storage storage, GameHost host, AudioManager audio)
             interactive = host.Window != null;
             config = new TestBrowserConfig(storage);
 
-            exit = host.Exit;
+            if (host.CanExit)
+                exit = host.Exit;
+            else if (host.CanSuspendToBackground)
+                exit = () => host.SuspendToBackground();
 
             audio.AddAdjustment(AdjustableProperty.Frequency, audioRateAdjust);
 
@@ -320,7 +323,7 @@ protected override bool OnKeyDown(KeyDownEvent e)
                 switch (e.Key)
                 {
                     case Key.Escape:
-                        exit();
+                        exit?.Invoke();
                         return true;
                 }
             }