NSInvalidArgumentException, reason: 'Invalid type in JSON write (__NSDate)'

Question

I\'m getting this exception when I try to JSON encode NSDate object.I believe NSDate is not compatible for JSON encoding. but I must encode the date.Any solutions?

Answer 1

You must convert the date to a string before you try to encode it. There are enough examples everywhere so it should be easy to find

Answer 2

Have you tried ?

updateDate = [NSNumber numberWithFloat:[[NSDate date] timeIntervalSince1970]];

As Described Here : SDK not supporting NSDate objects

Follow these Steps :

1. Convert the Date in JSON Format :

 NSDateFormatter *formatter = [[[NSDateFormatter alloc] init]autorelease];
 [formatter setDateFormat:@"Z"];
 NSString *updateDate = [NSString stringWithFormat:@"/Date(%.0f000%@)/", [[NSDate date] timeIntervalSince1970],[formatter stringFromDate:[NSDate date]]];

2. Embed In some array and POST the array.

Answer 3

As noted, you must first convert your NSDate to an NSString. It's not immediately clear, however, which format the date should be represented in. The answer can be found here: "JSON itself does not specify how dates should be represented, but Javascript does" -- ISO8601.

Here is an ISO8601 conversion method from a helper category for NSDate, courtesy Erica Sadun:

- (NSString *)ISO8601 {
    struct tm time;
    time_t interval = [self timeIntervalSince1970];
    gmtime_r(&interval, &time);
    char *x = calloc(1, 21);
    strftime_l(x, 20, "%FT%TZ", &time, gmtlocale);
    NSString *string = [NSString stringWithUTF8String:x];
    free(x);
    return string;
}

If you get an ISO8601 string back in a JSON payload and want to convert it to an NSDate, use this class method for NSDate:

+ (NSDate *)dateFromISO8601:(NSString *)string {
    if(!string) return nil;
    if (![string isKindOfClass:[NSString class]]) return nil;
    struct tm time;
    strptime_l([string UTF8String], "%FT%TZ", &time, gmtlocale);
    return [NSDate dateWithTimeIntervalSince1970:timegm(&time)];
}

Answer 4

The simplest way to store and retrieve a NSDate object in JSON would be to use the timeIntervalSince1970 property of NSDate.

The returned NSTimeInterval (double) is pretty standard and can easily be converted back to a NSDate object using:

NSDate dateWithTimeIntervalSince1970:<#(NSTimeInterval)#>

Answer 5

Convert NSDate to NSString and try to encode.

- (NSString *) changeDateToDateString :(NSDate *) date {

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
    NSLocale *locale = [NSLocale currentLocale];
    NSString *dateFormat = [NSDateFormatter dateFormatFromTemplate:@"hh mm" options:0 locale:locale];
    [dateFormatter setDateFormat:dateFormat];
    [dateFormatter setLocale:locale];
    NSString *dateString = [dateFormatter stringFromDate:date];
    return dateString;
}

Answer 6

FIrst store your data in NSString. And then convert your string to NSDate.

You can refer SO:

Converting NSString to NSDate (and back again)

NSString to NSDate conversion problem

How to convert NSString to NSDate using NSDateFormatter?