AutoLayout in UITableview with dynamic cell height - ios

Question

For dynamic height of my table view cell I take reference from this link.
Using Auto Layout in UITableView for dynamic cell layouts & variable row heights
Here is my code of tableview data source and delegate methods
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;
{
return arrTemp. count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier=#"AutoLAyoutCell";
AutoLayoutTableViewCell *cell=(AutoLayoutTableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell==nil) {
for (id currentObject in [[NSBundle mainBundle] loadNibNamed:#"AutoLayoutTableViewCell" owner:self options:nil]) {
if ([currentObject isKindOfClass:[UITableViewCell class]]) {
cell = (AutoLayoutTableViewCell *)currentObject;
break;
}
}
}
cell.IBlblLineNo.text=[NSString stringWithFormat:#"Line:%i",indexPath.row];
cell.IBlblLineText.text=[arrTemp objectAtIndex:indexPath.row];
[cell setNeedsUpdateConstraints];
[cell updateConstraintsIfNeeded];
CGSize expectedlineLabelSize = [cell.IBlblLineText.text sizeWithFont:cell.IBlblLineText.font constrainedToSize:CGSizeMake(280, 1000) lineBreakMode:NSLineBreakByTruncatingTail];
cell.IBlblLineText.numberOfLines=expectedlineLabelSize.height/17;
CGRect frmlbl=cell.IBlblLineText.frame;
frmlbl.size.height=expectedlineLabelSize.height;
cell.IBlblLineText.frame=frmlbl;
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
AutoLayoutTableViewCell *cell = (AutoLayoutTableViewCell *)[IBtblAutoLayoutExample cellForRowAtIndexPath:indexPath];
cell.IBlblLineNo.text=[NSString stringWithFormat:#"Line:%i",indexPath.row];
cell.IBlblLineText.text=[arrTemp objectAtIndex:indexPath.row];
[cell setNeedsUpdateConstraints];
[cell updateConstraintsIfNeeded];
CGSize expectedlineLabelSize = [cell.lineLabel.text sizeWithFont:cell.lineLabel.font constrainedToSize:CGSizeMake(280, 1000) lineBreakMode:NSLineBreakByWordWrapping];
cell.IBlblLineText.numberOfLines=expectedlineLabelSize.height/17;
CGRect frmlbl=cell.IBlblLineText.frame;
frmlbl.size.height=expectedlineLabelSize.height;
cell.IBlblLineText.frame=frmlbl;
CGFloat height = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
height += 1.0f;
return height;
}
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath
{
AutoLayoutTableViewCell *cell = (AutoLayoutTableViewCell *)[IBtblAutoLayoutExample cellForRowAtIndexPath:indexPath];
CGSize expectedlineLabelSize = [cell.IBlblLineText.text sizeWithFont:cell.IBlblLineText.font constrainedToSize:CGSizeMake(280, 1000) lineBreakMode:NSLineBreakByTruncatingTail];
return expectedlineLabelSize.height;
}
I have 2 questions :
My issue is I get the error EXE_BAD_EXCESS near the line
AutoLayoutTableViewCell *cell = (AutoLayoutTableViewCell *)[IBtblAutoLayoutExample cellForRowAtIndexPath:indexPath];
in heightForRowAtIndexPath and estimatedHeightForRowAtIndexPath.
Why do I have to write label text in both cellForRowAtIndexPath and heightForRowAtIndexPath?
Also, am I missing anything needed to achieve dynamic height for the cell?

Answer 1

To set automatic dimension for row height & estimated row height, ensure following steps to make, auto dimension effective for cell/row height layout.
Assign and implement tableview dataSource and delegate
Assign UITableViewAutomaticDimension to rowHeight & estimatedRowHeight
Implement delegate/dataSource methods (i.e. heightForRowAt and return a value UITableViewAutomaticDimension to it)
-
Objective C:
// in ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
#property IBOutlet UITableView * table;
#end
// in ViewController.m
- (void)viewDidLoad {
[super viewDidLoad];
self.table.dataSource = self;
self.table.delegate = self;
self.table.rowHeight = UITableViewAutomaticDimension;
self.table.estimatedRowHeight = UITableViewAutomaticDimension;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return UITableViewAutomaticDimension;
}
Swift:
#IBOutlet weak var table: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
// Don't forget to set dataSource and delegate for table
table.dataSource = self
table.delegate = self
// Set automatic dimensions for row height
// Swift 4.2 onwards
table.rowHeight = UITableView.automaticDimension
table.estimatedRowHeight = UITableView.automaticDimension
// Swift 4.1 and below
table.rowHeight = UITableViewAutomaticDimension
table.estimatedRowHeight = UITableViewAutomaticDimension
}
// UITableViewAutomaticDimension calculates height of label contents/text
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
// Swift 4.2 onwards
return UITableView.automaticDimension
// Swift 4.1 and below
return UITableViewAutomaticDimension
}
For label instance in UITableviewCell
Set number of lines = 0 (& line break mode = truncate tail)
Set all constraints (top, bottom, right left) with respect to its superview/ cell container.
Optional: Set minimum height for label, if you want minimum vertical area covered by label, even if there is no data.
Note: If you've more than one labels (UIElements) with dynamic length, which should be adjusted according to its content size: Adjust 'Content Hugging and Compression Resistance Priority` for labels which you want to expand/compress with higher priority.