在項目中遇到兩個等高寬的UILabel，一個文字2個字，另一個4個字。這時候排版要求是2個字是居左居右排版，

查看了UILabel的textAlignment屬性有

NSTextAlignmentLeft      = 0,    // Visually left aligned
NSTextAlignmentCenter    = 1,    // Visually centered
NSTextAlignmentRight     = 2,    // Visually right aligned
NSTextAlignmentRight     = 1,    // Visually right aligned
NSTextAlignmentCenter    = 2,    // Visually centered
NSTextAlignmentJustified = 3,    // Fully-justified. The last line in a paragraph is natural-aligned.
NSTextAlignmentNatural   = 4,    // Indicates the default alignment for script

沒有找到左右的屬性。

寫一個Category，利用#import <CoreText/CoreText.h>對文字進行處理。

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

@implementation UILabel (AlignmentMethod)

- (void)alignmentMethodLeftAndRight {
    [self layoutIfNeeded];

    CGSize textSize = [self.text boundingRectWithSize:CGSizeMake(self.frame.size.width, MAXFLOAT)
                                              options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesFontLeading
                                           attributes:@{NSFontAttributeName :self.font}
                                              context:nil].size;
    
    //計算字間距
    CGFloat margin = (self.frame.size.width - textSize.width) / (self.text.length - 1);
    NSNumber *number = [NSNumber numberWithFloat:margin];
    
    //修改默認字間距離
    NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc]initWithString:self.text];
    [attributeString addAttribute:(id)kCTKernAttributeName value:number range:NSMakeRange(0, self.text.length -1 )];
    self.attributedText = attributeString;
}
@end

實現結果

Paste_Image.png

Paste_Image.png