日期

void other()
{
    // 获得NSCalendar
    NSCalendar *calendar = nil;
    if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) {
        calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
    } else {
        calendar = [NSCalendar currentCalendar];
    }
    
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
    
    NSLog(@"%zd", [calendar isDateInToday:[fmt dateFromString:@"2016-05-08 01:09:56"]]);
    
}

void dateCompare3()
{
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";

    // 时间字符串
    NSString *createdAtString = @"2015-11-01 09:10:05";
    NSDate *createdAtDate = [fmt dateFromString:createdAtString];

    // 其他时间
    NSString *otherString = @"2015-10-31 08:56:45";
    NSDate *otherDate = [fmt dateFromString:otherString];

    // 获得NSCalendar
    NSCalendar *calendar = nil;
    
    if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) {
        calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
    } else {
        calendar = [NSCalendar currentCalendar];
    }

    // 获得日期之间的间隔
    NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
    NSDateComponents *cmps = [calendar components:unit fromDate:createdAtDate toDate:otherDate options:0];
    
    NSLog(@"%@", cmps);
}

void dateCompare2()
{
    // 时间字符串
    NSString *createdAtString = @"2015-11-20 09:10:05";
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
    NSDate *createdAtDate = [fmt dateFromString:createdAtString];

    // 手机当前时间
    //    NSDate *nowDate = [NSDate date];

    // 获得createdAtDate和nowDate的时间间隔(间隔多少秒)
    //    NSTimeInterval interval = [nowDate timeIntervalSinceDate:createdAtDate];
    NSTimeInterval interval = [createdAtDate timeIntervalSinceNow];
    
    NSLog(@"%f", interval);
}

void dateCompare()
{
    // 时间字符串
    NSString *createdAtString = @"2015-11-20 11:10:05";
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
    NSDate *createdAtDate = [fmt dateFromString:createdAtString];

    // 手机当前时间
    NSDate *nowDate = [NSDate date];

    /**
     NSComparisonResult的取值
     NSOrderedAscending = -1L, // 升序, 越往右边越大
     NSOrderedSame,  // 相等
     NSOrderedDescending // 降序, 越往右边越小
     */
    // 获得比较结果(谁大谁小)
    NSComparisonResult result = [nowDate compare:createdAtDate];
    if (result == NSOrderedAscending) { // 升序, 越往右边越大
        NSLog(@"createdAtDate > nowDate");
    } else if (result == NSOrderedDescending) { // 降序, 越往右边越小
        NSLog(@"createdAtDate < nowDate");
    } else {
        NSLog(@"createdAtDate == nowDate");
    }
}

/**
 *  日期元素 : 年月日时分秒
 */
void getComponentsOfDate3()
{
    // 时间字符串
    NSString *string = @"2015-11-20 09:10:05";

    // 日期格式化类
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    // 设置日期格式(为了转换成功)
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";

    // NSString * -> NSDate *
    NSDate *date = [fmt dateFromString:string];

    // 利用NSCalendar处理日期
    NSCalendar *calendar = [NSCalendar currentCalendar];

    NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
    NSDateComponents *cmps = [calendar components:unit  fromDate:date];

    //    NSLog(@"%zd %zd %zd", cmps.year, cmps.month, cmps.day);
    NSLog(@"%@", cmps);
}

/**
 *  日期元素 : 年月日时分秒
 */
void getComponentsOfDate2()
{
    // 时间字符串
    NSString *string = @"2015-11-20 09:10:05";

    // 日期格式化类
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    // 设置日期格式(为了转换成功)
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";

    // NSString * -> NSDate *
    NSDate *date = [fmt dateFromString:string];

    // 利用NSCalendar处理日期
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSInteger month = [calendar component:NSCalendarUnitMonth fromDate:date];
    NSInteger hour = [calendar component:NSCalendarUnitHour fromDate:date];
    NSInteger minute = [calendar component:NSCalendarUnitMinute fromDate:date];
    

    NSLog(@"%zd %zd %zd", month, hour, minute);
}

/**
 *  日期元素 : 年月日时分秒
 */
void getComponentsOfDate()
{
    // 时间字符串
    NSString *string = @"2015-11-20 09:10:05";
    

    NSString *month = [string substringWithRange:NSMakeRange(5, 2)];

    NSLog(@"%@", month);
}

void date2string()
{
    NSDate *date = [NSDate date];

    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyy年MM月dd号 HH:mm:ss";

    NSString *string = [fmt stringFromDate:date];
    
    NSLog(@"----%@+++++", string);
    
}

void string2date4()
{
    // 时间戳 : 从1970年1月1号 00:00:00开始走过的毫秒数

    // 时间字符串 - 时间戳
    NSString *string = @"1745645645645";
    
    NSTimeInterval second = string.longLongValue / 1000.0;

    // 时间戳 -> NSDate *
    NSDate *date = [NSDate dateWithTimeIntervalSince1970:second];
    
    NSLog(@"%@", date);
}

void string2date3()
{
    // 时间字符串
    NSString *string = @"Tue May 31 17:46:55 +0800 2011";

    // 日期格式化类
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"EEE MMM dd HH:mm:ss Z yyyy";
    // fmt.dateFormat = @"EEE MMM dd HH:mm:ss ZZZZ yyyy";
    // 设置语言区域(因为这种时间是欧美常用时间)
    fmt.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US"];

    NSLog(@"%@", [fmt dateFromString:string]);
}

void string2date2()
{
    // 时间字符串
    NSString *string = @"11月-20号/2015年 09-10:05秒";

    // 日期格式化类
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"MM月-dd号/yyyy年 HH-mm:ss秒";

    NSLog(@"%@", [fmt dateFromString:string]);
}

void string2date()
{
    // 时间字符串
    NSString *string = @"2015-11-20 09:33:22";

    // 日期格式化类
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    // 设置日期格式(为了转换成功)
    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";

    // NSString * -> NSDate *
    NSDate *date = [fmt dateFromString:string];
    
    NSString *newStr = [fmt stringFromDate:date];

    NSLog(@"%@", date);
    NSLog(@"%@", newStr);
    
}