UILabel如何实现两端对齐

UILabel似乎并没有提供两端对齐的方法，本人写了一个UILabel的(Category)；

引入头文件#import <CoreText/CoreText.h>

- (void)changeAlignmentRightAndLeft {

    CGSize textSize = [self.textboundingRectWithSize:CGSizeMake(self.frame.size.width,MAXFLOAT)options:NSStringDrawingUsesLineFragmentOrigin |NSStringDrawingTruncatesLastVisibleLineattributes:@{NSFontAttributeName :self.font}context:nil].size;

    CGFloat margin = (self.frame.size.width - textSize.width) / (self.text.length - 1);

    NSNumber *number = [NSNumbernumberWithFloat:margin];

    NSMutableAttributedString *attributedString = [[NSMutableAttributedStringalloc]initWithString:self.text];

    [attributedString addAttribute:(id)kCTKernAttributeNamevalue:numberrange:NSMakeRange(0,self.text.length -1)];

    self.attributedText = attributedString;

}