Allow silent sound

app/src/main/java/eu/faircode/email/Core.java

@@ -3149,8 +3149,10 @@ class Core {
             Log.i("Notify light enabled");
         }
 
+        if (!"".equals(sound)) {
+            // Not silent sound
             Uri uri = (sound == null ? null : Uri.parse(sound));
-        if (uri == null || !"content".equals(uri.getScheme()))
+            if (uri != null && !"content".equals(uri.getScheme()))
                 uri = null;
             Log.i("Notify sound=" + uri);
 
@@ -3158,6 +3160,7 @@ class Core {
                 def |= DEFAULT_SOUND;
             else
                 builder.setSound(uri);
+        }
 
         builder.setDefaults(def);
     }

app/src/main/java/eu/faircode/email/FragmentOptionsNotifications.java

@@ -436,7 +436,7 @@ public class FragmentOptionsNotifications extends FragmentBase implements Shared
             switch (requestCode) {
                 case ActivitySetup.REQUEST_SOUND:
                     if (resultCode == RESULT_OK && data != null)
-                        onSelectSound((Uri) data.getParcelableExtra(RingtoneManager.EXTRA_RINGTONE_PICKED_URI));
+                        onSelectSound(data.getParcelableExtra(RingtoneManager.EXTRA_RINGTONE_PICKED_URI));
                     break;
             }
         } catch (Throwable ex) {
@@ -446,13 +446,16 @@ public class FragmentOptionsNotifications extends FragmentBase implements Shared
 
     private void onSelectSound(Uri uri) {
         Log.i("Selected ringtone=" + uri);
-        if (uri != null && !"content".equals(uri.getScheme()))
-            uri = null;
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
-        if (uri == null)
+
-            prefs.edit().remove("sound").apply();
+        if (uri == null) // silent sound
-        else
+            prefs.edit().putString("sound", "").apply();
+        else {
+            if ("content".equals(uri.getScheme()))
                 prefs.edit().putString("sound", uri.toString()).apply();
+            else
+                prefs.edit().remove("sound").apply();
+        }
     }
 }