【iOS界面开发】iOS下，UILabel自适应高度的方法

来源：互联网发布：黑帽seo赚钱编辑：程序博客网时间：2024/06/07 09:17

主要思路是通过调用UILabel的- (CGSize)sizeThatFits:(CGSize)size方法来得到label的自适应高度值。

注意这里不能调用NSString的- (CGSize)sizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size lineBreakMode:(NSLineBreakMode)lineBreakMode方法来获得高度，因为如果未来label的可以配置其他行间距，自定义字体等等，那么此方法便会失效。其实，iOS的UILabel已经可以支持不同的字体属性，比如大小，颜色。所以此方法已经不再是正确的了

1.针对非AutoLayout的情况，直接调整frame：

- (void)autoHeightOfLabel:(UILabel *)label{    //Calculate the expected size based on the font and linebreak mode of your label    // FLT_MAX here simply means no constraint in height    CGSize maximumLabelSize = CGSizeMake(label.frame.size.width, FLT_MAX);    CGSize expectedLabelSize = [label sizeThatFits:maximumLabelSize];    //adjust the label the the new height.    CGRect newFrame = label.frame;    newFrame.size.height = expectedLabelSize.height;    label.frame = newFrame;    [label updateConstraintsIfNeeded];}

2.针对AutoLayout的情况，需要更新约束：

- (void)autoHeightOfLabel:(UILabel *)label{    //Calculate the expected size based on the font and linebreak mode of your label    // FLT_MAX here simply means no constraint in height    CGSize maximumLabelSize = CGSizeMake(label.frame.size.width, FLT_MAX);    //add the new height constraint to the label    for (NSLayoutConstraint *constraint in label.constraints) {        if (constraint.firstItem == label && constraint.firstAttribute == NSLayoutAttributeHeight && constraint.secondItem == nil) {            constraint.constant = expectedLabelSize.height;            break;        }    }}

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