Ugly heightForRowAtIndexPath and cellForRowAtIndexPath - iphone

Question

I have a UItableview, which I'm populating with data, using heightForRowAtIndexPath and cellForRowAtIndexPath. Apparently Apple makes me do things in my code twice.
First I have to calculate the size of my views (for that I have to make them) in heightForRowAtIndexPath and then I have to make them again, to add them to the actual view.
I have a pretty complicated view, so it looks double ugly, when you have to write it twice.
Isn't there a better way to do this?
UPDATE
This is how my code looks. It's not totally the same, but pretty close. Why in the world does apple make me write this twice?
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
NSLog(#"heightForRowAtIndexPath");
//Initiating strings
NSString *headlineString;
NSString *subHeadlineString;
NSString *bylineString;
if (global.magazine.issues.count==0) {
return 45;
}else if(indexPath.section == global.magazine.issues.count+1) {
//Finding the right issue and article for this row
Issue *issue = [global.magazine.issues objectAtIndex:global.magazine.issues.count-1];
//Creating the headline
headlineString = [NSString stringWithFormat:#"<span class='bold_style'>FOREWORD</span>"];
//Creating the subHeadline
subHeadlineString = [NSString stringWithFormat:#"%#", [issue.magazine_foreword substringToIndex:100]];
//Creating byline
bylineString = [[NSString stringWithFormat:#"<span class='ital_style'>By %#</span>", issue.magazine_byline] capitalizedString];
}else{
//Finding the right issue and article for this row
Issue *issue = [global.magazine.issues objectAtIndex:indexPath.section-1];
Article *article = [issue.articles objectAtIndex:indexPath.row];
//Creating the headline
headlineString = [NSString stringWithFormat:#"<span class='bold_style'>%#</span>", [article.title uppercaseString]];
//Creating the subHeadline
subHeadlineString = [NSString stringWithFormat:#"%#", [article.main_text substringToIndex:100]];
//Creating byline
bylineString = [NSString stringWithFormat:#"<span class='ital_style'>By %#</span>", article.byline];
}
//Creating the labels
NMCustomLabel *headline = [global.label headLineLabelWithString:headlineString fromTop:30 withWidth:global.screenWidth-60];
NMCustomLabel *subHeadline = [global.label subHeadlineLabelWithString:subHeadlineString fromTop:30+headline.height+10 withWidth:global.screenWidth-60];
NMCustomLabel *byline = [global.label articleBylineLabelWithString:bylineString fromTop:30+headline.height+10+subHeadline.height+10 withWidth:global.screenWidth-60];
//Setting the height of the row
return 30+headline.height+10+subHeadline.height+10+byline.height+30;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
NSLog(#"cellForRowAtIndexPath");
//Preparing the cell
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if (cell == nil) {
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
//Removing former text views
for (UIView *subview in [cell subviews]) {
if (subview.tag == 21 || subview.tag == 22 || subview.tag == 23) [subview removeFromSuperview];
}
//Removing and setting tableview border
[[cell viewWithTag:30] removeFromSuperview];
UIView *rightBorder = [[UIView alloc] initWithFrame:CGRectMake(cell.width-1, 0, 1, cell.height)];
rightBorder.backgroundColor = global.lightGrey;
rightBorder.tag = 30;
[cell addSubview:rightBorder];
//Setting the seletion background color on the cells
UIView *bgColorView = [[UIView alloc] init];
bgColorView.backgroundColor = global.extraLightGrey;
cell.selectedBackgroundView = bgColorView;
if (global.magazine.issues.count==0) {
return cell;
}else if (indexPath.section-1 == global.magazine.issues.count) {
//Finding the right issue and article for this row
Issue *issue = [global.magazine.issues objectAtIndex:global.magazine.issues.count-1];
//Creating the headline
NSString *headlineString = [NSString stringWithFormat:#"<span class='bold_style'>FOREWORD</span>"];
NMCustomLabel *headline = [global.label headLineLabelWithString:headlineString fromTop:30 withWidth:global.screenWidth-60];
headline.tag = 21;
[cell addSubview:headline];
//Creating the subHeadline
NSString *subHeadlineString = [[NSString stringWithFormat:#"%#", issue.magazine_foreword] substringToIndex:100];
NMCustomLabel *subHeadline = [global.label subHeadlineLabelWithString:subHeadlineString fromTop:30+headline.height+10 withWidth:global.screenWidth-60];
subHeadline.tag = 22;
[cell addSubview:subHeadline];
//Creating byline
NSString *bylineString = [[NSString stringWithFormat:#"<span class='ital_style'>By %#</span>", issue.magazine_byline] capitalizedString];
NMCustomLabel *byline = [global.label articleBylineLabelWithString:bylineString fromTop:30+headline.height+10+subHeadline.height+10 withWidth:global.screenWidth-60];
byline.tag = 23;
[cell addSubview:byline];
}else{
//Finding the right issue and article for this row
Issue *issue = [global.magazine.issues objectAtIndex:indexPath.section-1];
Article *article = [issue.articles objectAtIndex:indexPath.row];
//Creating the headline
NSString *headlineString = [NSString stringWithFormat:#"<span class='bold_style'>%#</span>", [article.title uppercaseString]];
NMCustomLabel *headline = [global.label headLineLabelWithString:headlineString fromTop:30 withWidth:global.screenWidth-60];
headline.tag = 21;
[cell addSubview:headline];
//Creating the subHeadline
NSString *subHeadlineString = [NSString stringWithFormat:#"%#", [article.main_text substringToIndex:100]];
NMCustomLabel *subHeadline = [global.label subHeadlineLabelWithString:subHeadlineString fromTop:30+headline.height+10 withWidth:global.screenWidth-60];
subHeadline.tag = 22;
[cell addSubview:subHeadline];
//Creating byline
NSString *bylineString = [[NSString stringWithFormat:#"<span class='ital_style'>By %#</span>", article.byline] capitalizedString];
NMCustomLabel *byline = [global.label articleBylineLabelWithString:bylineString fromTop:30+headline.height+10+subHeadline.height+10 withWidth:global.screenWidth-60];
byline.tag = 23;
[cell addSubview:byline];
}
return cell;
}

Answer 1

The easiest solution is to follow DRY principles and either add height as a property of the objects you are using as a datasource or add a method to your view controller such as:
-(CGFloat)calculateHeightForHeadline:(NSString*)headline andSubHeadline:(NSString*)subHeadline andByLine:(NSString*)byLine
Then at least you only have the calculation code in one place.
Alternatively, you could call [tableView heightForRowAtIndexPath:indexPath] from your cellForRowAtIndexPath method

Answer 2

You have to do it twice because the table view needs to know how tall it is in total before it draws anything - so it calls the height method for every row before it calls any cell method. With your current code, depending on the number of rows, you may be experiencing a slight delay before the table appears - instruments will show you that it is the height method you're spending time in.
I don't know what you custom label classes do but you may be able to calculate the height without having to create views (which is expensive) by using the string or attributed string drawing and size calculation UIKit extensions, which were created for this exact purpose.

Answer 3

heightForRowAtIndexPath
Will be called for all your rows. This delegate method returns the height for your rows. As your design required different height for each rows depending upon the condition. Unfortunately you'll have to calculate the row height each time before your row gets created. It's like we are deciding just before drawing the row what will be it's hight.
There's one way you can avoid this. But I won't advice you to go for it. Because it'll change the design of your UITableView. What you can do is you can decide the maximum height of your row out of all the possible conditions you have. For eg. Let's consider it as 100 pixel. Then you can draw your rest of the cells. However, that'll leave empty space if any of your row is less then 100 pixel. And it'll look shaggy.
Basically, to meet your requirement you'll have to do this twice. No other choice :-(

Answer 4

I wonder, why are you creating your custom labels in heightForRowAtIndexpath? Why don't you just calculate the size of the text with sizeWithFont: or such methods? I think that would be a better way to calculate height of the row. Good Luck!