UIFont?*theFont? = [UIFont?systemFontOfSize:14];

NSString?*strText =?@"這是一段很長(zhǎng)的字符串，我們將根據(jù)要求的字體大小，來(lái)計(jì)算實(shí)際需要的寬度和高度！";

1.計(jì)算文本的寬度

NSMutableDictionary?*dic?=?[NSMutableDictionary?dictionaryWithObject:[UIFont?systemFontOfSize:14]?forKey:NSFontAttributeName];??

CGSize?size?=?[strText?boundingRectWithSize:CGSizeMake(MAXFLOAT,?0.0)?options:NSStringDrawingUsesLineFragmentOrigin?attributes:dic?context:nil].size; ?

2.計(jì)算文本的高度

NSMutableDictionary?*dic?=?[NSMutableDictionary?dictionaryWithObject:[UIFont?systemFontOfSize:14]?forKey:NSFontAttributeName];??

CGSize?size?=?[strText?boundingRectWithSize:CGSizeMake(100.0,?MAXFLOAT)?options:NSStringDrawingUsesLineFragmentOrigin?attributes:dic?context:nil].size;??

這樣，用boundingRectWithSize:方法得到了，長(zhǎng)度和寬度，就可以對(duì)容器的大小進(jìn)行控制。