Android compatibility fixes

* doc/emacs/android.texi (Android Windowing): Document
restrictions on number of windows under Android 4.4 and earlier.

* java/AndroidManifest.xml.in <EmacsActivity>
<EmacsOpenActivity, EmacsMultitaskActivity>: Assign each class
of activity a unique task affinity.

* java/org/gnu/emacs/EmacsDesktopNotification.java (display1):
Remove redundant priority assignment.

* java/org/gnu/emacs/EmacsOpenActivity.java (onCreate): Handle
file URIs when processing attachments from a mailto URI, and
check for KitKat before opening content ones.

* java/org/gnu/emacs/EmacsWindow.java <pointerMap>
(figureChange): Replace coordinate HashMap with a SparseArray.

* java/org/gnu/emacs/EmacsWindowAttachmentManager.java
(registerWindow): Don't specify FLAG_ACTIVITY_NEW_DOCUMENT on
systems where it is absent.

5 files changed, 64 insertions, 30 deletions

diff --git a/java/AndroidManifest.xml.in b/java/AndroidManifest.xml.in
index 4d23c752747..563914fb02c 100644
--- a/java/AndroidManifest.xml.in
+++ b/java/AndroidManifest.xml.in
@@ -218,6 +218,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
 
     <activity android:name="org.gnu.emacs.EmacsActivity"
               android:launchMode="singleInstance"
+              android:taskAffinity="emacs.primary_frame"
               android:windowSoftInputMode="adjustResize"
               android:exported="true"
               android:configChanges="orientation|screenSize|screenLayout|keyboardHidden|locale|fontScale">
@@ -229,7 +230,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
     </activity>
 
     <activity android:name="org.gnu.emacs.EmacsOpenActivity"
-              android:taskAffinity="open.dialog"
+              android:taskAffinity="emacs.open_dialog"
               android:excludeFromRecents="true"
               android:exported="true">
 
@@ -273,6 +274,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
     </activity>
 
     <activity android:name="org.gnu.emacs.EmacsMultitaskActivity"
+              android:taskAffinity="emacs.secondary_frame"
               android:windowSoftInputMode="adjustResize"
               android:exported="true"
               android:configChanges="orientation|screenSize|screenLayout|keyboardHidden|locale|fontScale"/>
diff --git a/java/org/gnu/emacs/EmacsDesktopNotification.java b/java/org/gnu/emacs/EmacsDesktopNotification.java
index c80aa21b4fe..72569631a8c 100644
--- a/java/org/gnu/emacs/EmacsDesktopNotification.java
+++ b/java/org/gnu/emacs/EmacsDesktopNotification.java
@@ -208,22 +208,6 @@ public final class EmacsDesktopNotification
            distinct categories, but permit an importance to be
            assigned to each individual notification.  */
 
-        switch (importance)
-          {
-          case 2: /* IMPORTANCE_LOW */
-          default:
-            priority = Notification.PRIORITY_LOW;
-            break;
-
-          case 3: /* IMPORTANCE_DEFAULT */
-            priority = Notification.PRIORITY_DEFAULT;
-            break;
-
-          case 4: /* IMPORTANCE_HIGH */
-            priority = Notification.PRIORITY_HIGH;
-            break;
-          }
-
         builder = new Notification.Builder (context);
         builder.setContentTitle (title);
         builder.setContentText (content);
@@ -231,15 +215,28 @@ public final class EmacsDesktopNotification
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
           {
+            switch (importance)
+              {
+              case 2: /* IMPORTANCE_LOW */
+              default:
+                priority = Notification.PRIORITY_LOW;
+                break;
+
+              case 3: /* IMPORTANCE_DEFAULT */
+                priority = Notification.PRIORITY_DEFAULT;
+                break;
+
+              case 4: /* IMPORTANCE_HIGH */
+                priority = Notification.PRIORITY_HIGH;
+                break;
+              }
+
             builder.setPriority (priority);
             insertActions (context, builder);
             notification = builder.build ();
           }
         else
           notification = builder.getNotification ();
-
-        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN)
-          notification.priority = priority;
       }
     else
       {
diff --git a/java/org/gnu/emacs/EmacsOpenActivity.java b/java/org/gnu/emacs/EmacsOpenActivity.java
index 2cdfa2ec776..327a53bc417 100644
--- a/java/org/gnu/emacs/EmacsOpenActivity.java
+++ b/java/org/gnu/emacs/EmacsOpenActivity.java
@@ -535,7 +535,9 @@ public final class EmacsOpenActivity extends Activity
                   uri = intent.getParcelableExtra (Intent.EXTRA_STREAM);
 
                 if ((scheme = uri.getScheme ()) != null
-                    && scheme.equals ("content"))
+                    && scheme.equals ("content")
+                    && (Build.VERSION.SDK_INT
+                        >= Build.VERSION_CODES.KITKAT))
                   {
                     tem1 = EmacsService.buildContentName (uri, resolver);
                     attachmentString = ("'(\"" + (tem1.replace ("\\", "\\\\")
@@ -543,6 +545,14 @@ public final class EmacsOpenActivity extends Activity
                                                   .replace ("$", "\\$"))
                                         + "\")");
                   }
+                else if (scheme != null && scheme.equals ("file"))
+                  {
+                    tem1 = uri.getPath ();
+                    attachmentString = ("'(\"" + (tem1.replace ("\\", "\\\\")
+                                                  .replace ("\"", "\\\"")
+                                                  .replace ("$", "\\$"))
+                                        + "\")");
+                  }
               }
             else
               {
@@ -567,7 +577,9 @@ public final class EmacsOpenActivity extends Activity
 
                         if (uri != null
                             && (scheme = uri.getScheme ()) != null
-                            && scheme.equals ("content"))
+                            && scheme.equals ("content")
+                            && (Build.VERSION.SDK_INT
+                                >= Build.VERSION_CODES.KITKAT))
                           {
                             tem1
                               = EmacsService.buildContentName (uri, resolver);
@@ -577,6 +589,16 @@ public final class EmacsOpenActivity extends Activity
                                             .replace ("$", "\\$"));
                             builder.append ("\"");
                           }
+                        else if (scheme != null
+                                 && scheme.equals ("file"))
+                          {
+                            tem1 = uri.getPath ();
+                            builder.append ("\"");
+                            builder.append (tem1.replace ("\\", "\\\\")
+                                            .replace ("\"", "\\\"")
+                                            .replace ("$", "\\$"));
+                            builder.append ("\"");
+                          }
                       }
 
                     builder.append (")");
@@ -604,7 +626,13 @@ public final class EmacsOpenActivity extends Activity
           {
             fileName = null;
 
-            if (scheme.equals ("content"))
+            if (scheme.equals ("content")
+                /* Retrieving the native file descriptor of a
+                   ParcelFileDescriptor requires Honeycomb, and
+                   proceeding without this capability is pointless on
+                   systems before KitKat, since Emacs doesn't support
+                   opening content files on those.  */
+                && Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
               {
                 /* This is one of the annoying Android ``content''
                    URIs.  Most of the time, there is actually an
diff --git a/java/org/gnu/emacs/EmacsWindow.java b/java/org/gnu/emacs/EmacsWindow.java
index 93a512cc7ef..2baede1d2d0 100644
--- a/java/org/gnu/emacs/EmacsWindow.java
+++ b/java/org/gnu/emacs/EmacsWindow.java
@@ -23,7 +23,6 @@ import java.lang.IllegalStateException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.ListIterator;
-import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
@@ -50,6 +49,7 @@ import android.view.View;
 import android.view.ViewManager;
 import android.view.WindowManager;
 
+import android.util.SparseArray;
 import android.util.Log;
 
 import android.os.Build;
@@ -109,7 +109,7 @@ public final class EmacsWindow extends EmacsHandleObject
 
   /* Map between pointer identifiers and last known position.  Used to
      compute which pointer changed upon a touch event.  */
-  private HashMap<Integer, Coordinate> pointerMap;
+  private SparseArray<Coordinate> pointerMap;
 
   /* The window consumer currently attached, if it exists.  */
   private EmacsWindowAttachmentManager.WindowConsumer attached;
@@ -166,7 +166,7 @@ public final class EmacsWindow extends EmacsHandleObject
     super (handle);
 
     rect = new Rect (x, y, x + width, y + height);
-    pointerMap = new HashMap<Integer, Coordinate> ();
+    pointerMap = new SparseArray<Coordinate> ();
 
     /* Create the view from the context's UI thread.  The window is
        unmapped, so the view is GONE.  */
@@ -1001,7 +1001,8 @@ public final class EmacsWindow extends EmacsHandleObject
       case MotionEvent.ACTION_CANCEL:
         /* Primary pointer released with index 0.  */
         pointerID = event.getPointerId (0);
-        coordinate = pointerMap.remove (pointerID);
+        coordinate = pointerMap.get (pointerID);
+        pointerMap.delete (pointerID);
         break;
 
       case MotionEvent.ACTION_POINTER_DOWN:
@@ -1020,7 +1021,8 @@ public final class EmacsWindow extends EmacsHandleObject
         /* Pointer removed.  Remove it from the map.  */
         pointerIndex = event.getActionIndex ();
         pointerID = event.getPointerId (pointerIndex);
-        coordinate = pointerMap.remove (pointerID);
+        coordinate = pointerMap.get (pointerID);
+        pointerMap.delete (pointerID);
         break;
 
       default:
diff --git a/java/org/gnu/emacs/EmacsWindowAttachmentManager.java b/java/org/gnu/emacs/EmacsWindowAttachmentManager.java
index 18bdb6dbf60..aae4e2ee49b 100644
--- a/java/org/gnu/emacs/EmacsWindowAttachmentManager.java
+++ b/java/org/gnu/emacs/EmacsWindowAttachmentManager.java
@@ -124,10 +124,15 @@ public final class EmacsWindowAttachmentManager
 
     intent = new Intent (EmacsService.SERVICE,
                          EmacsMultitaskActivity.class);
-    intent.addFlags (Intent.FLAG_ACTIVITY_NEW_DOCUMENT
-                     | Intent.FLAG_ACTIVITY_NEW_TASK
+
+    intent.addFlags (Intent.FLAG_ACTIVITY_NEW_TASK
                      | Intent.FLAG_ACTIVITY_MULTIPLE_TASK);
 
+    /* Intent.FLAG_ACTIVITY_NEW_DOCUMENT is lamentably unavailable on
+       older systems than Lolipop.  */
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
+      intent.addFlags (Intent.FLAG_ACTIVITY_NEW_DOCUMENT);
+
     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N)
       EmacsService.SERVICE.startActivity (intent);
     else