Multiline UILabels With Auto layout - ios

Question

I have been trying for the last 2 days to get a UITableViewCell to do the following manual calculation.
CGFloat availableWidthForValueLabel = availableWidth * 0.7f;
CGSize valueLabelFitSize = [_valueLabel sizeThatFits:CGSizeMake(availableWidthForValueLabel, MAXFLOAT)];
_valueLabel.frame = CGRectMake(availableWidth - valueLabelFitSize.width, 0, valueLabelFitSize.width, valueLabelFitSize.height);
CGFloat availableWidthForKeyLabel = availableWidth - CGRectGetWidth(_valueLabel.frame);
CGSize keyLabelFitSize = [_keyLabel sizeThatFits:CGSizeMake(availableWidthForKeyLabel, MAXFLOAT)];
CGFloat keyLabelX = CGRectGetMinX(_valueLabel.frame) - keyLabelFitSize.width;
I have two multi-lined labels (key, value) in a view.
The value is anchored to the right of the view the Key is anchored to the left of the view with right aligned text.
I want to evaluate the values width/height first with a maximum width of 0.7 * view width then want the key to take up the rest of the available space in the view.
This works fine for single lines labels, but as not for multi-lined labels.
I have tried setting the preferredMaxLayoutWidth of the value label in both the updateConstraints and layoutSubview in the cell but what seems to happen is the hight of the cell grow incorrectly so big gaps appear in the cell.
- (void)updateConstraints
{
[super updateConstraints];
// value width
CGFloat width = ceil(self.keyValueSection.bounds.size.width * kValueMaxLenghtOfParentView);
if (self.valueLabel.preferredMaxLayoutWidth != width )
{
self.valueLabel.preferredMaxLayoutWidth = width;
}
// dec width
if (!self.decSection.hidden)
{
width = ceil(self.holderSection.bounds.size.width * kDecMaxLengthOfParentView);
if (self.decLabel.preferredMaxLayoutWidth != width )
{
self.decLabel.preferredMaxLayoutWidth = width;
}
}
// key width
width = floor(self.keyValueSection.bounds.size.width - kKeyValueGap - self.valueLabel.bounds.size.width);
if(self.keyLabel.preferredMaxLayoutWidth != width)
{
self.keyLabel.preferredMaxLayoutWidth = width;
}
}
I have tried everything I can find on the web and it all nearly works. I have tried setting the hugging and compression ratio but.

Answer 1

While this might not be the most elegant solution, i have fond a way to do what i want.
I use Autolayout to position the labels using constraints for vertical spacing >=0 top and bottom and centre Y alignment. I then specific the constraints for leading and trailing between the labels.
I then give each label a height and width constraint, and use the sizeTofit method to workout what the constants should be and update them when I set the labels text/atttributed text properties.
self.keyLabel.text = model.lineKey;
if ([model.lineValue isKindOfClass:[NSString class]]) {
self.valueLabel.text = model.lineValue;
}
else if ([model.lineValue isKindOfClass:[NSAttributedString class]])
{
self.valueLabel.attributedText = model.lineValue;
}
else
{
self.valueLabel.text = nil;
self.valueLabel.attributedText = nil;
}
self.keyValueGap.constant = kKeyValueGap;
CGFloat availableWidth = CGRectGetWidth(self.keyValueSection.bounds);
CGFloat availableWidthForValueLabel = availableWidth * 0.5f;
CGSize valueLabelFitSize = [self.valueLabel sizeThatFits:CGSizeMake(availableWidthForValueLabel, MAXFLOAT)];
self.valueHeight.constant = valueLabelFitSize.height;
self.valueWidth.constant = valueLabelFitSize.width;
CGFloat availableWidthForkeyLabel = availableWidth - valueLabelFitSize.width - kKeyValueGap;
CGSize keyLabelFitSize = [self.keyLabel sizeThatFits:CGSizeMake(availableWidthForkeyLabel, MAXFLOAT)];
self.keyHeight.constant = keyLabelFitSize.height;
self.keyWidth.constant = availableWidthForkeyLabel;
If anyone else has any better ideas :) - i would love to hear them as i do not like manually calculations while using autolayout