UITableViewCell update image on willDisplayCell - objective-c

Question

I am trying to update the second last row of a tableview just after the last one (of the same kind) has been inserted. What I want is to change the image in a custom uiimageview i put in the xib.
I achieved this feature by calling [_tableView reloadData] just after the insertion, but this way the insert animation has gone and the performance have got worse.
Here is part of the code I wrote:
•in the delegate:
-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
[_dataSource setIsRead:(BOOL)read AtIndexPath:indexPath];
[_dataSource configureCell:(WMChatTableViewCell *)cell AtIndexPath:indexPath];
[cell setNeedsUpdateConstraints];
[cell updateConstraintsIfNeeded];
[cell setNeedsLayout];
[cell layoutIfNeeded];
}
• in the dataSource
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
WMMessage *message = [self messageAtIndexPath:indexPath];
/**
Message sent by the user
*/
if ([message.sender_id intValue] == [[[NSUserDefaults standardUserDefaults]valueForKey:kUserIdKey]intValue]) {
WMRightChatTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:rightTextIdentifier];
if (cell == nil) {
cell = [[WMRightChatTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:rightTextIdentifier];
}
[self configureCell:cell AtIndexPath:indexPath];
return cell;
}
/**
Message sent by the recipient
*/
else{
WMLeftChatTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:leftTextIdentifier];
if (cell == nil) {
cell = [[WMLeftChatTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:leftTextIdentifier];
}
[self configureCell:cell AtIndexPath:indexPath];
return cell;
}
return nil;
}
-(void)configureCell:(WMChatTableViewCell *)cell AtIndexPath:(NSIndexPath *)indexPath{
WMMessage *message = [self messageAtIndexPath:indexPath];
....
/**
Last message sent by the recipient
*/
if (!([message.sender_id intValue] == [[[NSUserDefaults standardUserDefaults]valueForKey:kUserIdKey]intValue]) &&
[message isEqual:[[_messagesMatrix lastObject]lastObject]]) {
/**
An highlighted version of the background.
Normally the left cell has the "BoxChat_sx" image, only when it's the last one, the image should change
*/
[cell.balloonImageView setImage:[UIImage imageNamed:#"BoxChat_sx_new"]];
....
}
else if(!([message.sender_id intValue] == [[[NSUserDefaults standardUserDefaults]valueForKey:kUserIdKey]intValue])){
/*
If it's not the last anymore, the image should change back to it's original state
*/
[cell.balloonImageView setImage:[UIImage imageNamed:#"BoxChat_sx"]];
...
}
}
Without calling [_tableView reloadData] this code won't update the imageView. Is there a way to achieve this feature without calling reloadData or, at least, keeping the insertion animation?