2013-11-13 23:37

UILabel sizeToFit doesn't work with autolayout ios6 - iOS7使用StoryBoard时Label的宽度无法调整解决办法。

To make your label automatically resize height you need to do following:

  1. Set layout constrains for label
  2. Set height constraint with low priority. It should be lower than ContentCompressionResistancePriority
  3. Set numberOfLines = 0
  4. Set ContentHuggingPriority higher than label's height priority
  5. Set preferredMaxLayoutWidth for label. That value is used by label to calculate its height

For example:

self.descriptionLabel = [[UILabel alloc] init];
self.descriptionLabel.numberOfLines = 0;
self.descriptionLabel.lineBreakMode = NSLineBreakByWordWrapping;
self.descriptionLabel.preferredMaxLayoutWidth = 200;

[self.descriptionLabel setContentHuggingPriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];
[self.descriptionLabel setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];
[self.descriptionLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
[self addSubview:self.descriptionLabel];

NSArray* constrs = [NSLayoutConstraint constraintsWithVisualFormat:@"|-8-[descriptionLabel_]-8-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(descriptionLabel_)];
[self addConstraints:constrs];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-8-[descriptionLabel_]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(descriptionLabel_)]];
[self.descriptionLabel addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[descriptionLabel_(220@300)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(descriptionLabel_)]];

Using Interface Builder

  1. Set up four constraints. The height constraint is mandatory. enter image description here
  2. Then go to the label's attributes inspector and set number of lines to 0. enter image description here
  3. Go to the label's size inspector and increase vertical ContentHuggingPriority and vertical ContentCompressionResistancePriority.
    enter image description here
  4. Select and edit height constraint.
    enter image description here
  5. And decrease height constraint priority.
    enter image description here

原文地址:http://stackoverflow.com/questions/16009405/uilabel-sizetofit-doesnt-work-with-autolayout-ios6