CGFloat height =[@"填入Label.text"boundingRectWithSize:CGSizeMake(@“宽度”, CGFLOAT_MAX)
options:NSStringDrawingUsesLineFragmentOrigin
attributes:[NSDictionary dictionaryWithObject:[UIFont systemFontOfSize:15]
forKey:NSFontAttributeName] context:nil].size.height;
切圆角
Label.layer.cornerRadius = 5;//半径
Label.layer.masksToBound = YES;