show jids from address book in Start Conversation screen if only one account is used

src/main/java/eu/siacs/conversations/entities/Contact.java

@@ -156,6 +156,9 @@ public class Contact implements ListItem, Blockable {
 		if (isBlocked()) {
 			tags.add(new Tag(context.getString(R.string.blocked), 0xff2e2f3b));
 		}
+		if (showInPhoneBook()) {
+			tags.add(new Tag(context.getString(R.string.phone_book), 0xFF1E88E5));
+		}
 		return tags;
 	}
 
@@ -336,6 +339,10 @@ public class Contact implements ListItem, Blockable {
 				|| (this.getOption(Contact.Options.DIRTY_PUSH));
 	}
 
+	public boolean showInPhoneBook() {
+		return systemAccount != null && !systemAccount.trim().isEmpty();
+	}
+
 	public void parseSubscriptionFromElement(Element item) {
 		String ask = item.getAttribute("ask");
 		String subscription = item.getAttribute("subscription");

src/main/java/eu/siacs/conversations/ui/StartConversationActivity.java

@@ -858,11 +858,13 @@ public class StartConversationActivity extends XmppActivity implements XmppConne
 
 	protected void filterContacts(String needle) {
 		this.contacts.clear();
-		for (Account account : xmppConnectionService.getAccounts()) {
+		final List<Account> accounts = xmppConnectionService.getAccounts();
+		final boolean singleAccountActive = isSingleAccountActive(accounts);
+		for (Account account : accounts) {
 			if (account.getStatus() != Account.State.DISABLED) {
 				for (Contact contact : account.getRoster().getContacts()) {
 					Presence.Status s = contact.getShownStatus();
-					if (contact.showInRoster() && contact.match(this, needle)
+					if ((contact.showInRoster() || (singleAccountActive && contact.showInPhoneBook())) && contact.match(this, needle)
 							&& (!this.mHideOfflineContacts
 							|| (needle != null && !needle.trim().isEmpty())
 							|| s.compareTo(Presence.Status.OFFLINE) < 0)) {
@@ -875,6 +877,16 @@ public class StartConversationActivity extends XmppActivity implements XmppConne
 		mContactsAdapter.notifyDataSetChanged();
 	}
 
+	private static boolean isSingleAccountActive(final List<Account> accounts) {
+		int i = 0;
+		for(Account account : accounts) {
+			if (account.getStatus() != Account.State.DISABLED) {
+				++i;
+			}
+		}
+		return i == 1;
+	}
+
 	protected void filterConferences(String needle) {
 		this.conferences.clear();
 		for (Account account : xmppConnectionService.getAccounts()) {

src/main/res/values/strings.xml

@@ -724,4 +724,5 @@
     <string name="providing_a_name_is_optional">Providing a name is optional</string>
     <string name="create_dialog_group_chat_name">Group chat name</string>
     <string name="conference_destroyed">This group chat has been destroyed</string>
+    <string name="phone_book">Address book</string>
 </resources>