Port to Android API 36

* java/AndroidManifest.xml.in: Update targetSdkVersion to 36.

* java/INSTALL: Document revised compilation dependencies.

* java/org/gnu/emacs/EmacsActivity.java (interceptBackGesture):
New function.
(onCreate): Invoke the same to register back gesture callbacks
on Android 16 or better.

* java/org/gnu/emacs/EmacsWindow.java (onBackInvoked): New
function.

* src/keyboard.c (lispy_function_keys): Amend with new symbols
introduced in Android API 36.

1 files changed, 63 insertions, 0 deletions

diff --git a/java/org/gnu/emacs/EmacsActivity.java b/java/org/gnu/emacs/EmacsActivity.java
index 439a8defa32..6970728998b 100644
--- a/java/org/gnu/emacs/EmacsActivity.java
+++ b/java/org/gnu/emacs/EmacsActivity.java
@@ -50,6 +50,11 @@ import android.view.WindowInsetsController;
 
 import android.widget.FrameLayout;
 
+import android.window.BackEvent;
+import android.window.OnBackAnimationCallback;
+import android.window.OnBackInvokedCallback;
+import android.window.OnBackInvokedDispatcher;
+
 public class EmacsActivity extends Activity
   implements EmacsWindowManager.WindowConsumer,
   ViewTreeObserver.OnGlobalLayoutListener
@@ -252,6 +257,59 @@ public class EmacsActivity extends Activity
     return window;
   }
 
+  private void
+  interceptBackGesture ()
+  {
+    OnBackInvokedDispatcher dispatcher;
+    int priority = OnBackInvokedDispatcher.PRIORITY_DEFAULT;
+    OnBackInvokedCallback callback;
+
+    dispatcher = getOnBackInvokedDispatcher ();
+    callback = new OnBackAnimationCallback () {
+	@Override
+	public void
+	onBackInvoked ()
+	{
+	  View view = EmacsActivity.this.getCurrentFocus ();
+	  EmacsWindow window;
+
+	  if (view instanceof EmacsView)
+	    {
+	      window = ((EmacsView) view).window;
+	      window.onBackInvoked ();
+	    }
+	}
+
+	/* The three functions are overridden to prevent a misleading
+	   back animation from being displayed, as Emacs intercepts all
+	   back gestures and will not return to the home screen.  */
+
+	@Override
+	public void
+	onBackCancelled ()
+	{
+
+	}
+
+	@Override
+	public void
+	onBackProgressed (BackEvent gestureEvent)
+	{
+
+	}
+
+	@Override
+	public void
+	onBackStarted (BackEvent gestureEvent)
+	{
+
+	}
+    };
+    dispatcher.registerOnBackInvokedCallback (priority, callback);
+  }
+
+
+
   @Override
   public void
   onCreate (Bundle savedInstanceState)
@@ -286,6 +344,11 @@ public class EmacsActivity extends Activity
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM)
       layout.setFitsSystemWindows (true);
 
+    /* Android 16 replaces KEYCODE_BACK with a callback registered at
+       the window level.  */
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.BAKLAVA)
+      interceptBackGesture ();
+
     /* Maybe start the Emacs service if necessary.  */
     EmacsService.startEmacsService (this);