Use androidx lib for backpressed callback (#20291)

* use androidx lib for backpressed callback

* Update API suppressions

---------

Co-authored-by: Julien Lebosquain <julien@lebosquain.net>

api/Avalonia.Android.nupkg.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- https://learn.microsoft.com/dotnet/fundamentals/package-validation/diagnostic-ids -->
+<Suppressions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
+  <Suppression>
+    <DiagnosticId>CP0008</DiagnosticId>
+    <Target>T:Avalonia.Android.AvaloniaActivity</Target>
+    <Left>baseline/Avalonia.Android/lib/net10.0-android36.0/Avalonia.Android.dll</Left>
+    <Right>current/Avalonia.Android/lib/net10.0-android36.0/Avalonia.Android.dll</Right>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0008</DiagnosticId>
+    <Target>T:Avalonia.Android.AvaloniaMainActivity</Target>
+    <Left>baseline/Avalonia.Android/lib/net10.0-android36.0/Avalonia.Android.dll</Left>
+    <Right>current/Avalonia.Android/lib/net10.0-android36.0/Avalonia.Android.dll</Right>
+  </Suppression>
+</Suppressions>

src/Android/Avalonia.Android/AvaloniaActivity.cs

@@ -20,13 +20,14 @@ namespace Avalonia.Android;
 /// Common implementation of android activity that is integrated with Avalonia views.
 /// If you need a base class for main activity of Avalonia app, see <see cref="AvaloniaMainActivity"/>.  
 /// </summary>
-public class AvaloniaActivity : AppCompatActivity, IAvaloniaActivity, IOnBackInvokedCallback
+public class AvaloniaActivity : AppCompatActivity, IAvaloniaActivity
 {
     private EventHandler<ActivatedEventArgs>? _onActivated, _onDeactivated;
     private GlobalLayoutListener? _listener;
     private object? _content;
     private bool _contentViewSet;
     internal AvaloniaView? _view;
+    private BackPressedCallback? _currentBackPressedCallback;
 
     public Action<int, Result, Intent?>? ActivityResult { get; set; }
     public Action<int, string[], Permission[]>? RequestPermissionsResult { get; set; }
@@ -127,7 +128,8 @@ public class AvaloniaActivity : AppCompatActivity, IAvaloniaActivity, IOnBackInv
 
         if (OperatingSystem.IsAndroidVersionAtLeast(33))
         {
-            OnBackInvokedDispatcher.UnregisterOnBackInvokedCallback(this);
+            _currentBackPressedCallback?.Remove();
+            _currentBackPressedCallback = null;
         }
         base.OnStop();
     }
@@ -138,7 +140,8 @@ public class AvaloniaActivity : AppCompatActivity, IAvaloniaActivity, IOnBackInv
 
         if (OperatingSystem.IsAndroidVersionAtLeast(33))
         {
-            OnBackInvokedDispatcher.RegisterOnBackInvokedCallback(IOnBackInvokedDispatcher.PriorityDefault, this);
+            _currentBackPressedCallback = new BackPressedCallback(this);
+            OnBackPressedDispatcher.AddCallback(this, _currentBackPressedCallback);
         }
         base.OnStart();
     }

src/Android/Avalonia.Android/BackPressedCallback.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using AndroidX.Activity;
+
+namespace Avalonia.Android
+{
+    internal class BackPressedCallback(AvaloniaActivity activity) : OnBackPressedCallback(true)
+    {
+        public override void HandleOnBackPressed()
+        {
+            activity.OnBackInvoked();
+        }
+    }
+}