UILabel的自适应宽高

文件 NSString+CZNSStringExt.h
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface NSString (CZNSStringExt)

//对象方法
- (CGSize)sizeOfTextWithMaxSize:(CGSize)maxSize font:(UIFont *)font;

//类方法
+ (CGSize)sizeWithText:(NSString *)text maxSize:(CGSize)maxSize font:(UIFont *)font;

@end

文件NSString+CZNSStringExt.m
#import "NSString+CZNSStringExt.h"

@implementation NSString (CZNSStringExt)

//实现对象方法
- (CGSize)sizeOfTextWithMaxSize:(CGSize)maxSize font:(UIFont *)font{
NSDictionary *attrs = @{NSFontAttributeName:font};

return [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;

}

//实现类方法（用传过来的text来调用）
+ (CGSize)sizeWithText:(NSString *)text maxSize:(CGSize)maxSize font:(UIFont *)font{

return [text sizeOfTextWithMaxSize:maxSize font:font];
}
@end