UILabel自动调整大小(高度，宽度)

设置行数为0

    UIFont * textFont = [UIFont systemFontOfSize:36];    //最大尺寸    // MAXFLOAT 为可设置的最大高度    CGSize size = CGSizeMake(300, MAXFLOAT);    //获取当前那本属性    NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:textFont,NSFontAttributeName, nil];    //实际尺寸    CGSize actualSize = [model.currentPrice boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin attributes:dic context:nil].size;