iOS学习——UILabel设置行间距和字间距

用一个封装起来的Category来调整这部分文字的行间距，其中5.0就是我自定义的文字间距：

[UILabel changeLineSpaceForLabel:cell.describeLabel WithSpace:5.0];

这是一个UILabel 的Category，他的内部实现是这样的：
UILabel+ChangeLineSpaceAndWordSpace.h

#import <UIKit/UIKit.h>

@interface UILabel (ChangeLineSpaceAndWordSpace)

/**
 *  改变行间距
 */
+ (void)changeLineSpaceForLabel:(UILabel *)label WithSpace:(float)space;

/**
 *  改变字间距
 */
+ (void)changeWordSpaceForLabel:(UILabel *)label WithSpace:(float)space;

/**
 *  改变行间距和字间距
 */
+ (void)changeSpaceForLabel:(UILabel *)label withLineSpace:(float)lineSpace WordSpace:(float)wordSpace;

@end

UILabel+ChangeLineSpaceAndWordSpace.m

#import "UILabel+ChangeLineSpaceAndWordSpace.h"

@implementation UILabel (ChangeLineSpaceAndWordSpace)

+ (void)changeLineSpaceForLabel:(UILabel *)label WithSpace:(float)space {
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:space];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
}

+ (void)changeWordSpaceForLabel:(UILabel *)label WithSpace:(float)space {
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText attributes:@{NSKernAttributeName:@(space)}];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
}

+ (void)changeSpaceForLabel:(UILabel *)label withLineSpace:(float)lineSpace WordSpace:(float)wordSpace {
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText attributes:@{NSKernAttributeName:@(wordSpace)}];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:lineSpace];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
}

@end