//获取字符串的宽度
-(float)widthForString:(NSString *)value fontSize:(float)fontSize andHeight:(float)height
{
    UIColor  *backgroundColor=[UIColor blackColor];
    UIFont *font=[UIFont boldSystemFontOfSize:fontSize];
    CGRect sizeToFit = [value boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, height) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{
                                                                                                                                             NSForegroundColorAttributeName:backgroundColor,
                                                                                                                                             NSFontAttributeName:font
                                                                                                                                             } context:nil];
    
    return sizeToFit.size.width;
}
//获得字符串的高度
-(float) heightForString:(NSString *)value fontSize:(float)fontSize andWidth:(float)width
{
    UIColor  *backgroundColor=[UIColor blackColor];
    UIFont *font=[UIFont boldSystemFontOfSize:18.0];
    CGRect sizeToFit = [value boundingRectWithSize:CGSizeMake(width, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{
                                       NSForegroundColorAttributeName:backgroundColor,
                                       NSFontAttributeName:font
                                       } context:nil];
    return sizeToFit.size.height;
}