如何从iOS中的格式化字符串中获取日期和时间

Question

I have a NSString "dateString" which contains date and time in given format.

"MM/dd/yyyy HH:mm:ss a" .

I want to fetch the data from the dateString using NSDateFormatter and then I'm trying to show in a String "strDate" . Im able to fetch the data but the only issue is that i'm not getting the correct value for "hour" place.

For Ex:

dateString   = 1/23/2015 7:06:37 AM
strDate   = 01/23/2015 00:06:37 am

How to resolve this issue. Thanks in advance. This is my code:

-(NSString *)getDateQuestion:(NSString *)dateString
{
NSLog(@"dateString   = %@",dateString);

//NSString to NSDate
NSDate          *datefromString  = [[NSDate alloc] init];
NSDateFormatter *dateFormatter   = [[NSDateFormatter alloc] init];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"GMT+5:30"]];
[dateFormatter setTimeZone: [NSTimeZone systemTimeZone]];

[dateFormatter setDateFormat:@"MM/dd/yyyy HH:mm:ss a"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

datefromString                   = [dateFormatter dateFromString:dateString];
NSLog(@"dateString1   = %@",datefromString);

//NSDate convert to NSString
 [dateFormatter setDateFormat:@"MM/dd/yyyy HH:mm:ss a"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"GMT+5:30"]];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

NSString       *strDate          = [dateFormatter stringFromDate:datefromString];
NSLog(@"strDate   = %@",strDate);

return strDate;
}

Answer 1

Just Pass Correct date Time string to the function and don't set time zone Unnecessary again and again... i hope it helps you...

NSDate *dat = [NSDate date];
NSDateFormatter *dateFormatter   = [[NSDateFormatter alloc] init];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"UTC+05:30"]];

[dateFormatter setDateFormat:@"MM/dd/yyyy HH:mm:ss a"];

NSString * dateString =[dateFormatter stringFromDate:dat];
NSLog(@"dateString   = %@",dateString);
NSLog(@"dateString1   = %@",dateString);

//NSDate convert to NSString
[dateFormatter setDateFormat:@"HH:mm:ss a"];

NSString       *strDate          = [dateFormatter stringFromDate:dat];
NSLog(@"strDate   = %@",strDate);

HH stands for 24hr.

hh satnds for 12 hr.

Answer 2

[dateFormatter setDateFormat:@"MM/dd/yyyy hh:mm:ss a"]; 

替换为"MM/dd/yyyy hh:mm:ss a"