I have a UICollectionView that contains dynamic content. The problem I am having is that when the cell is dequeued it forgets its state. In my - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath I have a boolean value that when it is true, it changes to a true image, but when it is false, it changes to a false image. However when I scroll down and back up, the cells forget there state. Is there a way to make a cell remember its state? Here is what is inside my
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
SalesCollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
SaleImage * saleImage = [self.SaleObjs objectAtIndex:indexPath.row];
cell.bgImageView.image = [UIImage imageNamed:saleImage.imageName];
if (saleImage.isBookable) {
cell.isBookable = YES;
}
else{
cell.isBookable=NO;
}
return cell;
}
I have a remedy for this but it effects performance. I add this to my custom cell;
-(void)prepareForReuse{
[super prepareForReuse];
[self setNeedsLayout];
}
Here is my collection view cell;
@implementation SalesCollectionViewCell
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.layer.cornerRadius = 6.0;
self.bgImageView = [[UIImageView alloc] init];
self.book = [[UILabel alloc] init];
[self.contentView insertSubview:self.bgImageView atIndex:0];
return self;
}
-(void)layoutSubviews{
[super layoutSubviews];
if (self.isBookable) {
self.book.frame =CGRectMake(0, self.bounds.size.height - 41, 140, 41);
self.book.text = @"Book this Item";
self.book.textColor = [UIColor whiteColor];
self.book.adjustsFontSizeToFitWidth=YES;
self.book.textAlignment = NSTextAlignmentCenter;
self.book.backgroundColor= [UIColor darkGrayColor];
self.book.font = [UIFont fontWithName:kAppFont size:17.0];
[self.contentView insertSubview:self.book atIndex:2];
self.bgImageView.frame =CGRectMake(0, 0, 140, self.bounds.size.height - self.book.bounds.size.height);
}
else{
self.bgImageView.frame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.height);
}
}
-(void)prepareForReuse{
[super prepareForReuse];
[self.book removeFromSuperview];
[self setNeedsLayout];
}
As @iphonic said, the isBookable property should be (re)moved from the cell completely. Cells in a UICollectionView are being reused most of the time, so even though your saleImage.isBookable is in the correct state your cell.isBookable is probably not.
I would do the following:
if(saleImage.isBookable){
self.bgImageView.frame = CGRectMake(0, 0, 140, self.bounds.size.height - self.book.bounds.size.height);
cell.bgImageView.image = [UIImage imageNamed:saleImage.imageName];
cell.book.hidden = NO;
}
else{
self.bgImageView.frame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.height);
cell.bgImageView.image = nil;
cell.book.hidden = YES;
}
[cell layoutIfNeeded];
inside collectionView: cellForItemAtIndexPath:.
I would also have finished setting up the book UILabel inside initWithFrame and have it initially hidden. Something like:
- (id)initWithFrame:(CGRect)frame{
self.layer.cornerRadius = 6.0;
self.bgImageView = [[UIImageView alloc] init];
[self.contentView insertSubview:self.bgImageView atIndex:0];
self.book = [[UILabel alloc] initWithFrame:CGRectMake(0, self.bounds.size.height - 41, 140, 41)];
self.book.text = @"Book this Item";
self.book.textColor = [UIColor whiteColor];
self.book.adjustsFontSizeToFitWidth=YES;
self.book.textAlignment = NSTextAlignmentCenter;
self.book.backgroundColor= [UIColor darkGrayColor];
self.book.font = [UIFont fontWithName:kAppFont size:17.0];
self.book.hidden = YES;
[self.contentView insertSubview:self.book atIndex:2];
}
Then you would not need to override layoutSubviews.
Hope that helps.
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