自适应高宽度

    CGSizesize =CGSizeMake(SCREEN_WIDTH-40,30*unitPX);//设置高度宽度的最大限度

    CGRect rect = [string boundingRectWithSize:size options:NSStringDrawingUsesFontLeading|NSStringDrawingTruncatesLastVisibleLine|NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : [UIFont systemFontOfSize:12*unitPX]} context:nil];

    returnrect.size.width+40*unitPX;