iOS 7: Get height for default UITableViewCell? - ios

Question

I'm using a default UITableViewCell, just its textLabel. My text is multi-line. What's the best way to compute its height?
I know there are various NSString sizing methods, but in order to use those, you have to specify a width. And I don't know the width of the default textLabel, and I suspect it changes based upon which text is placed inside it.
I've tried also using the method described here:
Using Auto Layout in UITableView for dynamic cell layouts & variable row heights
...but it doesn't work (estimated size always comes back 0); there's an implication in that post that that solution only works for UITableViewCell subclasses. (I could subclass, but it's not necessary.)
Suggestions? My app is iOS 7-specific.
Thanks!

Answer 1

UITableView rowHeight property. If you do not explicitly set it, UITableView sets it to a standard value.

Answer 2

I got it working with a standard UITableViewCell - using the github in the question you listed, but replace these functions.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.textLabel.lineBreakMode = UILineBreakModeWordWrap;
cell.textLabel.numberOfLines = 0;
cell.textLabel.font = [UIFont fontWithName:#"Helvetica" size:17.0];
}
// Configure the cell for this indexPath
//[cell updateFonts];
NSDictionary *dataSourceItem = [self.model.dataSource objectAtIndex:indexPath.row];
cell.textLabel.text =[dataSourceItem valueForKey:#"body"];
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSDictionary *dataSourceItem = [self.model.dataSource objectAtIndex:indexPath.row];
NSString *cellText = [dataSourceItem valueForKey:#"body"];
UIFont *cellFont = [UIFont fontWithName:#"Helvetica" size:17.0];
CGSize constraintSize = CGSizeMake(280.0f, MAXFLOAT);
CGSize labelSize = [cellText sizeWithFont:cellFont constrainedToSize:constraintSize lineBreakMode:UILineBreakModeWordWrap];
return labelSize.height;
}
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (self.isInsertingRow) {
// A constraint exception will be thrown if the estimated row height for an inserted row is greater
// than the actual height for that row. In order to work around this, we return the actual height
// for the the row when inserting into the table view.
// See: https://github.com/caoimghgin/TableViewCellWithAutoLayout/issues/6
return [self tableView:tableView heightForRowAtIndexPath:indexPath];
} else {
return 500.0f;
}
}
Oh also remove the register to the custom cell class so we get a UITableViewCell instead of RJTableViewCell. Also I think with this in here (even if it was a UITableViewCell) dequeueReusableCellWithIdentifier would never return nil and we wouldn't setup our cell correctly.
- (void)viewDidLoad
{
[super viewDidLoad];
//[self.tableView registerClass:[RJTableViewCell class] forCellReuseIdentifier:CellIdentifier];
...
}
Basically followed this example here - https://stackoverflow.com/questions/129502/how-do-i-wrap-text-in-a-uitableviewcell-without-a-custom-cell. I think the key is to not ask the cell for it's height like you do if you subclass the cell, but instead figure it out based on the text and font. The fact you can't ask the cell for it's hight seems a bit weird to me, and makes me think perhaps #Jeffery Thomas is right, it may be safer in the long run to just create a custom cell. Probably depends on your projet I would guess.

Answer 3

You need to subclass UITableViewCell.
You are asking more from UITableViewCell than it promises to provide. This is a recipe for trouble.
Create a subclass and build a prototype. You will know all the constraints, so this will be easy.