根据字符串计算宽度

//根据字符串计算宽度
-(CGFloat)WidthWithString:(NSString*)string fontSize:(CGFloat)fontSize height:(CGFloat)height
{
    NSDictionary *attrs = @{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]};
    return  [string boundingRectWithSize:CGSizeMake(0, height) options:NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:attrs context:nil].size.width;
}

获得字符串的高度

//获得字符串的高度
+(float) heightForString:(NSString *)value fontSize:(float)fontSize andWidth:(float)width
{
    CGSize sizeToFit = [value sizeWithFont:[UIFont systemFontOfSize:fontSize] constrainedToSize:CGSizeMake(width, CGFLOAT_MAX) lineBreakMode:NSLineBreakByCharWrapping];//此处的换行类型（lineBreakMode）可根据自己的实际情况进行设置
    return sizeToFit.height;
}