Fix displaying popup menus from a menu entry on Android

* java/org/gnu/emacs/EmacsActivity.java (EmacsActivity, onDestroy)
(onWindowFocusChanged): Keep track of the last focused activity.
* java/org/gnu/emacs/EmacsDialog.java (display1): Use it if
there is no current focus.

2 files changed, 35 insertions, 4 deletions

diff --git a/java/org/gnu/emacs/EmacsActivity.java b/java/org/gnu/emacs/EmacsActivity.java
index 30eaf85805a..3156a144a0f 100644
--- a/java/org/gnu/emacs/EmacsActivity.java
+++ b/java/org/gnu/emacs/EmacsActivity.java
@@ -47,6 +47,9 @@ public class EmacsActivity extends Activity
   /* List of activities with focus.  */
   public static List<EmacsActivity> focusedActivities;
 
+  /* The last activity to have been focused.  */
+  public static EmacsActivity lastFocusedActivity;
+
   /* The currently focused window.  */
   public static EmacsWindow focusedWindow;
 
@@ -215,6 +218,11 @@ public class EmacsActivity extends Activity
     manager.removeWindowConsumer (this, isMultitask || isFinishing ());
     focusedActivities.remove (this);
     invalidateFocus ();
+
+    /* Remove this activity from the static field, lest it leak.  */
+    if (lastFocusedActivity == this)
+      lastFocusedActivity = null;
+
     super.onDestroy ();
   }
 
@@ -223,7 +231,10 @@ public class EmacsActivity extends Activity
   onWindowFocusChanged (boolean isFocused)
   {
     if (isFocused && !focusedActivities.contains (this))
-      focusedActivities.add (this);
+      {
+        focusedActivities.add (this);
+        lastFocusedActivity = this;
+      }
     else
       focusedActivities.remove (this);
 
diff --git a/java/org/gnu/emacs/EmacsDialog.java b/java/org/gnu/emacs/EmacsDialog.java
index 7d88a23c58f..bd5e9ba8ee7 100644
--- a/java/org/gnu/emacs/EmacsDialog.java
+++ b/java/org/gnu/emacs/EmacsDialog.java
@@ -230,11 +230,31 @@ public class EmacsDialog implements DialogInterface.OnDismissListener
     AlertDialog dialog;
 
     if (EmacsActivity.focusedActivities.isEmpty ())
-      return false;
+      {
+        /* If focusedActivities is empty then this dialog may have
+           been displayed immediately after a popup dialog is
+           dismissed.  */
+
+        activity = EmacsActivity.lastFocusedActivity;
+
+        if (activity == null)
+          return false;
+      }
+    else
+      activity = EmacsActivity.focusedActivities.get (0);
 
-    activity = EmacsActivity.focusedActivities.get (0);
     dialog = dismissDialog = toAlertDialog (activity);
-    dismissDialog.show ();
+
+    try
+      {
+        dismissDialog.show ();
+      }
+    catch (Exception exception)
+      {
+        /* This can happen when the system decides Emacs is not in the
+           foreground any longer.  */
+        return false;
+      }
 
     /* If there are less than four buttons, then they must be
        individually enabled or disabled after the dialog is