iOS UILabel字间距适应宽度

原文：https://www.jianshu.com/p/2b1620944a90

效果如下：

image.png

给UILabel写一个分类：

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UILabel (AutoSpace)

//两端对齐
- (void)textAlignmentLeftAndRight;

- (void)textAlignmentLeftAndRightWith:(CGFloat)labelWidth;

@end

NS_ASSUME_NONNULL_END

#import "UILabel+AutoSpace.h"
#import <CoreText/CoreText.h>

@implementation UILabel (AutoSpace)

- (void)textAlignmentLeftAndRight {
    [self textAlignmentLeftAndRightWith:CGRectGetWidth(self.frame)];
}

- (void)textAlignmentLeftAndRightWith:(CGFloat)labelWidth {
    if (self.text == nil || self.text.length == 0) {
        return;
    }
    
    CGSize size = [self.text boundingRectWithSize:CGSizeMake(labelWidth, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:self.font} context:nil].size;
    NSInteger length = (self.text.length - 1);
    NSString *lastStr = [self.text substringWithRange:NSMakeRange(self.text.length - 1,1)];
    if ([lastStr isEqualToString:@":"] || [lastStr isEqualToString:@"："]) {
        length = (self.text.length - 2);
    }
    CGFloat margin = (labelWidth - size.width) / length;
    NSNumber *number = [NSNumber numberWithFloat:margin];
    NSMutableAttributedString *attribute = [[NSMutableAttributedString alloc]initWithString:self.text];
    [attribute addAttribute:NSKernAttributeName value:number range:NSMakeRange(0, length)];
    self.attributedText = attribute;
}

@end

在设置完label的frame、text、font等属性后再调用：

[myLabel textAlignmentLeftAndRight];