weird behavior on dynamic uitableviewcell height - ios

Question

Im trying to make dynamic uitableviewcell height for my custome cell.
the cell is subclassed for adding some background.
this is my uitableview controller class :
#define PADDING 23.0f
- (void)viewDidLoad
{
[super viewDidLoad];
[self.tableView setSeparatorStyle:UITableViewCellSeparatorStyleNone];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSUInteger count = [self.entries count];
return count + _rowcount;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *reuseIdentifier = #"PlaceholderCell2";
SubcategoryTableViewCell * sctvCell = [tableView dequeueReusableCellWithIdentifier:reuseIdentifier];
if (sctvCell == nil) {
sctvCell= [[SubcategoryTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier];
}
NSUInteger nodeCount = [self.entries count];
sctvCell.contentView.translatesAutoresizingMaskIntoConstraints = NO;
UILabel *label = (UILabel *)[sctvCell.contentView viewWithTag:1];
if (nodeCount > 0)
{
NewsFetchAppRecord *appRecord = [self.entries objectAtIndex:indexPath.row];
[label setText:appRecord.title];
NSDictionary *attributes = #{NSFontAttributeName: [UIFont fontWithName:#"B MyFont" size:14.0f]};
CGRect rect = [appRecord.title boundingRectWithSize:CGSizeMake(label.frame.size.height - PADDING * 5, MAXFLOAT)
options:NSStringDrawingUsesLineFragmentOrigin
attributes:attributes
context:nil];
CGRect newFrame = label.frame;
newFrame.size.height = rect.size.height;
label.frame = newFrame;
[label sizeToFit];
UIView *whiteRoundedCornerView = (UIView *)[sctvCell.contentView viewWithTag:1000];
CGRect newFrame2 = whiteRoundedCornerView.frame;
newFrame2.size.width = 300;
newFrame2.size.height = rect.size.height + 160;
[ whiteRoundedCornerView setFrame:newFrame2];
}
if ((unsigned long)indexPath.row == [self.entries count] - 1){
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0),
^{
NewsFetchParseOperation *p = [[NewsFetchParseOperation alloc]init];
NewsFetchAppRecord *appRecord = [self.entries objectAtIndex:indexPath.row];
p.cat = appRecord.Category;
self.intindex = self.intindex + 1;
p.index = [NSString stringWithFormat:#"%d", (int)self.intindex];
p.lastid = appRecord.ids;
[p main];
dispatch_async(dispatch_get_main_queue(), ^(void)
{
[self.tableView beginUpdates];
NSMutableArray *indexPaths = [NSMutableArray array];
NSInteger currentCount = self.entries.count;
for (NSUInteger i = 0; i < p.appRecordList.count; i++) {
[indexPaths addObject:[NSIndexPath indexPathForRow:currentCount+i inSection:0]];
}
NSArray *temp_1 =[self.entries arrayByAddingObjectsFromArray:p.appRecordList];
self.entries = temp_1;
[self.tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationLeft];
[self.tableView endUpdates];
});
});
}
return sctvCell;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *reuseIdentifier = #"PlaceholderCell2";
SubcategoryTableViewCell * sctvCell = [tableView dequeueReusableCellWithIdentifier:reuseIdentifier];
if (sctvCell == nil) {
sctvCell= [[SubcategoryTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier];
}
NewsFetchAppRecord *appRecord = [self.entries objectAtIndex:indexPath.row];
UILabel *label = (UILabel *)[sctvCell.contentView viewWithTag:1];
NSDictionary *attributes = #{NSFontAttributeName: [UIFont fontWithName:#"B MyFont" size:14.0f]};
CGRect rect = [appRecord.title boundingRectWithSize:CGSizeMake(label.frame.size.height - PADDING * 5, MAXFLOAT)
options:NSStringDrawingUsesLineFragmentOrigin
attributes:attributes
context:nil];
return rect.size.height + PADDING * 6;
}
and my cell subclass :
- (void)awakeFromNib {
self.news_img.layer.cornerRadius = 4;
self.news_img.clipsToBounds = YES;
self.resource_icon_img.layer.cornerRadius = 4;
self.resource_icon_img.clipsToBounds = YES;
self.contentView.backgroundColor = [UIColor clearColor];
self.whiteroundcorner = [[UIView alloc] initWithFrame:CGRectMake(10,10,300,250)];
self.whiteroundcorner.backgroundColor = [UIColor whiteColor];
self.whiteroundcorner.layer.masksToBounds = NO;
self.whiteroundcorner.layer.cornerRadius = 3.0;
[self.whiteroundcorner.layer setShadowColor:[UIColor grayColor].CGColor];
self.whiteroundcorner.layer.shadowOffset = CGSizeMake(-1, 1);
self.whiteroundcorner.layer.shadowOpacity = 0.2;
self.whiteroundcorner.tag = 1000;
[self.contentView addSubview:self.whiteroundcorner];
[self.contentView sendSubviewToBack:self.whiteroundcorner];
}
im using story board for my table like this :
now problem is most of time the height calculated incorrectly.
also some time the height goes way beyond on cell and in the end of 10 cell
when i try to fetch new row the last cell apears incorrectly.

Answer 1

You will need to calculate the height for the cell after setting its content.
So something like this:
- (CGFloat)heightForCellAtIndexPath:(NSIndexPath *)indexPath {
static UITableViewCell *sizingCell = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sizingCell = [self.tableView dequeueReusableCellWithIdentifier:cellIdentifier];
});
/* Method where you set the content of the cell */
[self configureCell: atIndexPath:indexPath];
return [self calculateHeightForConfiguredSizingCell:sizingCell];
}
- (CGFloat)calculateHeightForConfiguredSizingCell:(UITableViewCell *)sizingCell {
[sizingCell setNeedsDisplay];
[sizingCell layoutIfNeeded];
CGSize size = [sizingCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
return size.height;
}