email: prevent stock email app to unset firstSnippet on mark/unmark as read

If the email conversation only have one message then firstSnippet is the only valid
snippet in the converation item. Multiple conversation items are only supported by Gmail
which call the "set" method to set those snippets. This changes prevents to set
firstSnippet = null when user mark/unmark the item as read in stock email app.

Change-Id: I85f2ff0ab212c2a64450c3d46323418b9340fe40
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/com/android/mail/providers/ConversationInfo.java b/src/com/android/mail/providers/ConversationInfo.java
index 60d47e8b2..ebbc4044a 100644
--- a/src/com/android/mail/providers/ConversationInfo.java
+++ b/src/com/android/mail/providers/ConversationInfo.java
@@ -136,10 +136,13 @@ public class ConversationInfo implements Parcelable {
         for (ParticipantInfo pi : participantInfos) {
             changed |= pi.markRead(read);
         }
-        if (read) {
-            firstSnippet = lastSnippet;
-        } else {
-            firstSnippet = firstUnreadSnippet;
+        // Change the firstSnippet only if the conversion has messages.
+        if (messageCount > 0) {
+            if (read) {
+                firstSnippet = lastSnippet;
+            } else {
+                firstSnippet = firstUnreadSnippet;
+            }
         }
         return changed;
     }