iOS开发小知识之改变UIlabel的行间距和字间距

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原文链接: www.jianshu.com

在iOS开发中经常会用到UIlabel来展示一些文字性的内容,但是默认的文字排版会觉得有些挤,为了更美观也更易于阅读我们可以通过某些方法将UIlabel的行间距和字间距按照需要调节。

比如一个Label的默认间距效果是这样:

然后用一个封装起来的Category来调整这部分文字的行间

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

调整后的效果是这样的:

其中5.0就是我自定义的文字间距。

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

根据内部实现也可以自己灵活运用 不一定用Category的方法。