ignore bookmark name of 'None'

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

@@ -2,6 +2,7 @@ package eu.siacs.conversations.entities;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
@@ -55,18 +56,25 @@ public class Bookmark extends Element implements ListItem {
 	@Override
 	public String getDisplayName() {
 		final Conversation c = getConversation();
+		final String name = getBookmarkName();
 		if (c != null) {
 			return c.getName().toString();
-		} else if (getBookmarkName() != null
-				&& !getBookmarkName().trim().isEmpty()) {
-			return getBookmarkName().trim();
+		} else if (printableValue(name, false)) {
+			return name.trim();
 		} else {
 			Jid jid = this.getJid();
-			String name = jid != null ? jid.getLocal() : getAttribute("jid");
-			return name != null ? name : "";
+			return jid != null && jid.getLocal() != null ? jid.getLocal() : "";
 		}
 	}
 
+	public static boolean printableValue(@Nullable String value, boolean permitNone) {
+		return value != null && !value.trim().isEmpty() && (permitNone || !"None".equals(value));
+	}
+
+	public static boolean printableValue(@Nullable String value) {
+		return printableValue(value, true);
+	}
+
 	@Override
 	public Jid getJid() {
 		return this.jid;

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

@@ -5,6 +5,7 @@ import android.content.Context;
 import android.database.Cursor;
 import android.net.Uri;
 import android.provider.ContactsContract;
+import android.text.TextUtils;
 
 import org.json.JSONArray;
 import org.json.JSONException;
@@ -112,13 +113,13 @@ public class Contact implements ListItem, Blockable {
 	}
 
 	public String getDisplayName() {
-		if (Config.X509_VERIFICATION && this.commonName != null && !this.commonName.isEmpty()) {
+		if (Config.X509_VERIFICATION && !TextUtils.isEmpty(this.commonName)) {
 			return this.commonName;
-		} else if (this.systemName != null && !this.systemName.isEmpty()) {
+		} else if (!TextUtils.isEmpty(this.systemName)) {
 			return this.systemName;
-		} else if (this.serverName != null && !this.serverName.isEmpty()) {
+		} else if (!TextUtils.isEmpty(this.serverName)) {
 			return this.serverName;
-		} else if (this.presenceName != null && !this.presenceName.isEmpty() && mutualPresenceSubscription() ) {
+		} else if (!TextUtils.isEmpty(this.presenceName) && mutualPresenceSubscription() ) {
 			return this.presenceName;
 		} else if (jid.getLocal() != null) {
 			return JidHelper.localPartOrFallback(jid);
@@ -152,7 +153,7 @@ public class Contact implements ListItem, Blockable {
 	}
 
 	public boolean match(Context context, String needle) {
-		if (needle == null || needle.isEmpty()) {
+		if (TextUtils.isEmpty(needle)) {
 			return true;
 		}
 		needle = needle.toLowerCase(Locale.US).trim();

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

@@ -26,6 +26,8 @@ import eu.siacs.conversations.xmpp.chatstate.ChatState;
 import eu.siacs.conversations.xmpp.mam.MamReference;
 import rocks.xmpp.addr.Jid;
 
+import static eu.siacs.conversations.entities.Bookmark.printableValue;
+
 
 public class Conversation extends AbstractEntity implements Blockable, Comparable<Conversation> {
 	public static final String TABLENAME = "conversations";
@@ -479,15 +481,15 @@ public class Conversation extends AbstractEntity implements Blockable, Comparabl
 	public CharSequence getName() {
 		if (getMode() == MODE_MULTI) {
 			final String subject = getMucOptions().getSubject();
-			Bookmark bookmark = getBookmark();
+			final Bookmark bookmark = getBookmark();
 			final String bookmarkName = bookmark != null ? bookmark.getBookmarkName() : null;
-			if (subject != null && !subject.trim().isEmpty()) {
+			if (printableValue(subject)) {
 				return subject;
-			} else if (bookmarkName != null && !bookmarkName.trim().isEmpty()) {
+			} else if (printableValue(bookmarkName, false)) {
 				return bookmarkName;
 			} else {
-				String generatedName = getMucOptions().createNameFromParticipants();
-				if (generatedName != null) {
+				final String generatedName = getMucOptions().createNameFromParticipants();
+				if (printableValue(generatedName)) {
 					return generatedName;
 				} else {
 					return getJid().getLocal();