TableView reloadData does not remove images - ios7

Question

I have tableView with multiple types of dynamic prototype cells. When I call reloadData in viewDidLoad most of the data gets reloaded but the images remain and overlap with the new content. Is there another command that I'm missing?
Here's the code snippet (tried to edit it down for simplicity):
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
PFObject *question = [self.friendsPosts objectAtIndex:indexPath.row];
...
else if ([[question objectForKey:#"questionType"] isEqualToString:#"PhotoChoice"]) {
static NSString *CellIdentifier = #"PhotoChoiceCell";
PhotoChoiceTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
PFUser *asker = [question objectForKey:#"asker"];
[asker fetch];
cell.question = question;
cell.usernameLabel.text = asker.username;
cell.questionLabel.text = [question objectForKey:#"questionText"];
cell.delegate = self;
[cell setCellIndexPath:indexPath];
[cell.questionLabel adjustFontSizeToFit];
cell.answered = false;
NSDate *postedTime = [question createdAt];
NSString *postedAgo = [postedTime dateTimeAgo];
cell.timeLabel.text = postedAgo;
[cell.likeButton setTitle:[NSString stringWithFormat:#"Likes (%#)", [question objectForKey:#"likes"]] forState:UIControlStateNormal];
cell.commentButton.text = [NSString stringWithFormat:#"Comments (%lu)", (unsigned long)[[question objectForKey:#"comments" ] count]];
PFRelation *allAnswerers = [question objectForKey:#"answerersRelation"];
PFQuery *answerersQuery = [allAnswerers query];
[answerersQuery whereKey:#"objectId" equalTo:[[PFUser currentUser] objectId]];
[answerersQuery countObjectsInBackgroundWithBlock:^(int number, NSError *error) {
if (error) {
NSLog(#"Error %# %#", error, [error userInfo]);
}
else {
if (number == 0) {
if ( [[question objectForKey:#"numPhotos"] isEqualToString:#"2" ]) {
[cell.photoButtonA1 setImage:allImages[0] forState:UIControlStateNormal];
[cell.photoButtonA2 setImage:allImages[1] forState:UIControlStateNormal];
cell.photoButtonA1.hidden = NO;
cell.photoButtonA2.hidden = NO;
}
else if ( [[question objectForKey:#"numPhotos"] isEqualToString:#"3"] ) {
[cell.photoButtonB1 setImage:allImages[0] forState:UIControlStateNormal];
[cell.photoButtonB2 setImage:allImages[1] forState:UIControlStateNormal];
[cell.photoButtonB3 setImage:allImages[2] forState:UIControlStateNormal];
cell.photoButtonB1.hidden = NO;
cell.photoButtonB2.hidden = NO;
cell.photoButtonB3.hidden = NO;
}
else if ( [[question objectForKey:#"numPhotos"] isEqualToString:#"4"] ) {
[cell.photoButtonC1 setImage:allImages[0] forState:UIControlStateNormal];
[cell.photoButtonC2 setImage:allImages[1] forState:UIControlStateNormal];
[cell.photoButtonC3 setImage:allImages[2] forState:UIControlStateNormal];
[cell.photoButtonC4 setImage:allImages[3] forState:UIControlStateNormal];
cell.photoButtonC1.hidden = NO;
cell.photoButtonC2.hidden = NO;
cell.photoButtonC3.hidden = NO;
cell.photoButtonC4.hidden = NO;
}
}
So, I should have made it clear that the images were set as UIButtons.

Answer 1

OK, here is my guess:
You seem to have three types of cell: one with 2 images, one with 3, and one with 4; but they are all of the same class and use the same cell identifier.
So when you recycle (dequeue) your table cells, you might be reusing a cell that was previously assigned 4 images, but this time using it as a 2-image cell. Thus, you update only 2 images of the previous 4, and the other two remain unchanged. You should set the remaining images to nil when you set less than 4 images to a cell (2 or 3).
Although without further details on the pattern of occurrence of your bug, it is hard to tell.
Try this modification to your code:
// (previous code omitted)
if (number == 0) {
// Reset all cell images, regardless of type
[cell.photoButtonA1 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonA2 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonB1 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonB2 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonB3 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonC1 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonC2 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonC3 setImage:nil forState:UIControlStateNormal];
[cell.photoButtonC4 setImage:nil forState:UIControlStateNormal];
//
if ( [[question objectForKey:#"numPhotos"] isEqualToString:#"2" ]) {
[cell.photoButtonA1 setImage:allImages[0] forState:UIControlStateNormal];
[cell.photoButtonA2 setImage:allImages[1] forState:UIControlStateNormal];
cell.photoButtonA1.hidden = NO;
cell.photoButtonA2.hidden = NO;
}
else if ( [[question objectForKey:#"numPhotos"] isEqualToString:#"3"] ) {
[cell.photoButtonB1 setImage:allImages[0] forState:UIControlStateNormal];
[cell.photoButtonB2 setImage:allImages[1] forState:UIControlStateNormal];
[cell.photoButtonB3 setImage:allImages[2] forState:UIControlStateNormal];
cell.photoButtonB1.hidden = NO;
cell.photoButtonB2.hidden = NO;
cell.photoButtonB3.hidden = NO;
}
else if ( [[question objectForKey:#"numPhotos"] isEqualToString:#"4"] ) {
[cell.photoButtonC1 setImage:allImages[0] forState:UIControlStateNormal];
[cell.photoButtonC2 setImage:allImages[1] forState:UIControlStateNormal];
[cell.photoButtonC3 setImage:allImages[2] forState:UIControlStateNormal];
[cell.photoButtonC4 setImage:allImages[3] forState:UIControlStateNormal];
cell.photoButtonC1.hidden = NO;
cell.photoButtonC2.hidden = NO;
cell.photoButtonC3.hidden = NO;
cell.photoButtonC4.hidden = NO;
}
}
// (following code omitted)