日本のサマータイムに苦しめられた話 / japan_summertime

iOSDC Japan 2019
Day1 16:10〜 Track A
https://fortee.jp/iosdc-japan-2019/proposal/c677f8b6-25a1-4e87-beb1-689ef498a692

1. A J @ CD O! 901 0 06 L : 2/
    1
2. 
     @ ( ) 2 S O
3. 
    3
   
4. l / l / 4 6 0 6 9 @5 172
5. ) + 5     
   
    ( 0( + ) : @ 9 
    timezone "JST" NSDateFormatter
6. 6
       dateFormatter.dateFormat = @"yyyy/MM/dd"; //  → 
    [dateFormatter dateFromString:@"1951/05/06"]; [dateFormatter dateFromString:@"1951/05/07"]; 0
7. 
    7  2019/09/06 → 2019-09-05 15:00:00 +0000 2019-09-06 00:00:00 +0900
   ! "
8. 1951/05/06 → 1951-05-05 15:00:00 +0000 // iOS 9
    1951/05/06 → (null) // iOS 10
    1951/05/07 → 1951-05-06 14:00:00 +0000
    8 
   
9. 1951/05/06 → 1951-05-05 15:00:00 +0000 // iOS 9
    1951/05/06 → (null) // iOS 10
    1951/05/07 → 1951-05-06 14:00:00 +0000 9 6 / 0 9 5 1 
   
10. 1951/05/06 → 1951-05-05 15:00:00 +0000 // iOS 9
     1951/05/06 → (null) // iOS 10
     1951/05/07 → 1951-05-06 14:00:00 +0000 10 5 / 0 91 @9 @ 61 
    
11. 
     11
12. 12 5 9 @ 15 0 / 6 5
13. 13  
     !0
14. 14  
     ! " + 0 01 0
15. + 15  
     ! " 4 15 8 89 9 0 8
16. 16 : 0 0 !
17. 
     17 
         dateFormatter.dateFormat = @"yyyy/MM/dd HH:mm:ss"; NSDate *date = [dateFormatter dateFromString:@"1951/05/05 23:59:59"]; [date dateByAddingTimeInterval:1.f]; // `date`
    1
18.   18 
     1951/05/05 23:59:59 1951/05/06 01:00:00
    
19. 19 @ 1 1 1
20.   20  
21. dateFormatter.dateFormat = @"yyyy/MM/dd HH:mm:ss"; [dateFormatter dateFromString:@"1951/05/06 01:00:00"]; [dateFormatter dateFromString:@"1951/05/07 00:00:00"];
     21 + 1
22. //
    OS 1951/05/06 → 1951-05-05 15:00:00 +0000 1951/05/07 → 1951-05-06 14:00:00 +0000     22   
    
23. 
     23 J ! "
24. l +,
    !$ %(&)   l * '"#  ! 24 @ 
25. l 3 9 5 46490/4 8 464 @ l - 3 9 :44 .87 3884 4 07 0 / /. # 30 3884 25
26. 26   ! 
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