Fix crash when creating group with no avatar icon

Fixes #4320
// FREEBIE

src/org/thoughtcrime/securesms/GroupCreateActivity.java

@@ -26,6 +26,7 @@ import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.util.Log;
@@ -460,10 +461,12 @@ public class GroupCreateActivity extends PassphraseRequiredActionBarActivity {
     return handlePushOperation(groupId, groupName, avatar, memberE164Numbers);
   }
 
-  private Pair<Long, Recipients> handlePushOperation(byte[] groupId, String groupName, byte[] avatar,
+  private Pair<Long, Recipients> handlePushOperation(byte[] groupId, String groupName,
+                                                     @Nullable byte[] avatar,
                                                      Set<String> e164numbers)
       throws InvalidNumberException
   {
+    Attachment avatarAttachment = null;
     String     groupRecipientId = GroupUtil.getEncodedId(groupId);
     Recipients groupRecipient   = RecipientFactory.getRecipientsFromString(this, groupRecipientId, false);
 
@@ -474,8 +477,11 @@ public class GroupCreateActivity extends PassphraseRequiredActionBarActivity {
                                        .addAllMembers(e164numbers)
                                        .build();
 
+    if (avatar != null) {
       Uri avatarUri = SingleUseBlobProvider.getInstance().createUri(avatar);
-    Attachment                avatarAttachment = new UriAttachment(avatarUri, ContentType.IMAGE_JPEG, AttachmentDatabase.TRANSFER_PROGRESS_DONE, avatar.length);
+      avatarAttachment = new UriAttachment(avatarUri, ContentType.IMAGE_JPEG, AttachmentDatabase.TRANSFER_PROGRESS_DONE, avatar.length);
+    }
+
     OutgoingGroupMediaMessage outgoingMessage  = new OutgoingGroupMediaMessage(groupRecipient, context, avatarAttachment, System.currentTimeMillis());
     long                      threadId         = MessageSender.send(this, masterSecret, outgoingMessage, -1, false);
 

src/org/thoughtcrime/securesms/recipients/Recipient.java

@@ -43,8 +43,8 @@ public class Recipient {
 
   private final long recipientId;
 
-  private String  number;
-  private String  name;
+  private @NonNull  String  number;
+  private @Nullable String  name;
   private boolean stale;
 
   private ContactPhoto contactPhoto;
@@ -123,7 +123,7 @@ public class Recipient {
     notifyListeners();
   }
 
-  public String getNumber() {
+  public @NonNull String getNumber() {
     return number;
   }
 

src/org/thoughtcrime/securesms/recipients/RecipientFactory.java

@@ -58,11 +58,11 @@ public class RecipientFactory {
     return provider.getRecipients(context, ids, asynchronous);
   }
 
-  public static Recipient getRecipientForId(Context context, long recipientId, boolean asynchronous) {
+  public @NonNull static Recipient getRecipientForId(Context context, long recipientId, boolean asynchronous) {
     return provider.getRecipient(context, recipientId, asynchronous);
   }
 
-  public static Recipients getRecipientsForIds(Context context, long[] recipientIds, boolean asynchronous) {
+  public @NonNull static Recipients getRecipientsForIds(Context context, long[] recipientIds, boolean asynchronous) {
     return provider.getRecipients(context, recipientIds, asynchronous);
   }
 

src/org/thoughtcrime/securesms/recipients/RecipientProvider.java

@@ -70,7 +70,7 @@ public class RecipientProvider {
                                        ContactColors.UNKNOWN_COLOR));
   }};
 
-  Recipient getRecipient(Context context, long recipientId, boolean asynchronous) {
+  @NonNull Recipient getRecipient(Context context, long recipientId, boolean asynchronous) {
     Recipient cachedRecipient = recipientCache.get(recipientId);
     if (cachedRecipient != null && !cachedRecipient.isStale()) return cachedRecipient;
 
@@ -86,7 +86,7 @@ public class RecipientProvider {
     return cachedRecipient;
   }
 
-  Recipients getRecipients(Context context, long[] recipientIds, boolean asynchronous) {
+  @NonNull Recipients getRecipients(Context context, long[] recipientIds, boolean asynchronous) {
     Recipients cachedRecipients = recipientsCache.get(new RecipientIds(recipientIds));
     if (cachedRecipients != null && !cachedRecipients.isStale()) return cachedRecipients;