Added contact group to vCard import/export

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

@@ -168,6 +168,10 @@ public class EntityContact implements Serializable {
     }
 
     public static void update(Context context, long account, Address[] addresses, int type, long time) {
+        update(context, account, addresses, null, type, time);
+    }
+
+    public static void update(Context context, long account, Address[] addresses, String group, int type, long time) {
         if (addresses == null)
             return;
 
@@ -192,6 +196,7 @@ public class EntityContact implements Serializable {
                     contact.type = type;
                     contact.email = email;
                     contact.name = name;
+                    contact.group = group;
                     contact.avatar = (avatar == null ? null : avatar.toString());
                     contact.times_contacted = 1;
                     contact.first_contacted = time;
@@ -201,6 +206,8 @@ public class EntityContact implements Serializable {
                 } else {
                     if (contact.name == null && name != null)
                         contact.name = name;
+                    if (contact.group == null && group != null)
+                        contact.group = group;
                     contact.avatar = (avatar == null ? null : avatar.toString());
                     contact.times_contacted++;
                     contact.first_contacted = Math.min(contact.first_contacted, time);

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

@@ -71,6 +71,7 @@ import ezvcard.VCard;
 import ezvcard.VCardVersion;
 import ezvcard.io.text.VCardReader;
 import ezvcard.io.text.VCardWriter;
+import ezvcard.property.Categories;
 import ezvcard.property.Email;
 import ezvcard.property.FormattedName;
 
@@ -401,6 +402,11 @@ public class FragmentContacts extends FragmentBase {
                         FormattedName fn = vcard.getFormattedName();
                         String name = (fn == null) ? null : fn.getValue();
 
+                        List<String> categories = new ArrayList<>();
+                        if (vcard.getCategories() != null)
+                            categories.addAll(vcard.getCategories().getValues());
+                        String group = (categories.size() < 1 ? null : categories.get(0));
+
                         List<Address> addresses = new ArrayList<>();
                         for (Email email : emails) {
                             String address = email.getValue();
@@ -412,6 +418,7 @@ public class FragmentContacts extends FragmentBase {
                         EntityContact.update(context,
                                 account,
                                 addresses.toArray(new Address[0]),
+                                group,
                                 EntityContact.TYPE_TO,
                                 now);
                     }
@@ -474,6 +481,8 @@ public class FragmentContacts extends FragmentBase {
                         vcard.addEmail(contact.email);
                         if (!TextUtils.isEmpty(contact.name))
                             vcard.setFormattedName(contact.name);
+                        if (!TextUtils.isEmpty(contact.group))
+                            vcard.setCategories(contact.group);
                         vcards.add(vcard);
                     }