Adding an object to NSMutableArray causing crash

Question

I am trying to combine a string date and time then convert that to an NSDate. My code is:

NSMutableArray *arrayOfDatesAsDates = [[NSMutableArray alloc] init];

NSDateFormatter *dateAndTimeFormatter = [[NSDateFormatter alloc] init];    
[dateAndTimeFormatter setLocale:enUSPOSIXLocale];                           
[dateAndTimeFormatter setDateFormat:@"dd-MM-yyyy HH:mm"];

NSLog(@"here");
//create an NSDate with todays date and the right prayer time
NSString *prayerDateString = [curDate stringByAppendingString: @" "];
prayerDateString = [prayerDateString stringByAppendingString: timeOfMagrib];
NSDate *prayerDateAndTime = [dateAndTimeFormatter dateFromString:prayerDateString]; //convert string back to date
NSLog(@"nsdate %@", prayerDateAndTime);
[arrayOfDatesAsDates addObject:prayerDateAndTime];

The output to the log of prayerDateAndTime is 2013-07-08 20:26:00 +0000 as expected and the error message is Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'.

It crashes at the [arrayOfDatesAsDates addObject:prayerDateAndTime]; line.

Why is this?

Many thanks

"Why is this?" `-[__NSArrayM insertObject:atIndex:]: object cannot be nil'` — Hot Licks, Jul 08 '13 at 20:43
Did you debug and check the value? Is it being called multiple times so you see some good results in the log? — Wain, Jul 08 '13 at 20:43
You're basically trying to add into a NSArray a nil object, which it's not permitted. Check conversion between `NSDate` and `NSString`; it must return nil somewhere — HepaKKes, Jul 08 '13 at 20:44
You've got the NSLog there. You didn't notice that it's printing "(null)"??? — Hot Licks, Jul 08 '13 at 20:45
Yep all, as I said in the question, the output to the log of the second to last line is 2013-07-08 20:26:00 +0000, not nil... — samiles, Jul 08 '13 at 20:45
@samiles That's very suspicious. Are you sure that you pasted the text after `"nsdate "`, not before it? `NSLog` shows the time of the logging, and it will be very close to what you expect to see printed for `prayerDateAndTime`, so it is very easy to confuse one for the other. — Sergey Kalinichenko, Jul 08 '13 at 20:52
Can you post an exact copy of the relavent lines in the log? — George Mitchell, Jul 08 '13 at 21:04

score 1 · Accepted Answer · edited May 23 '17 at 12:21

It looks like [dateAndTimeFormatter dateFromString:@"2013-07-08 20:26:00 +0000"] is returning nil because your date string "2013-07-08 20:26:00 +0000" does not match your dateFormat: @"dd-MM-yyyy HH:mm" ... try running after replacing:

[dateAndTimeFormatter setDateFormat:@"dd-MM-yyyy HH:mm"]

with

[dateAndTimeFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss ZZZ"]
// you really want this to match:     2013-07-08 20:26:00 +0000
// yyyy: 2013, four digit year
// MM: two digit numerical month
// dd: day of month
// HH: 24 hour hour
// mm: two digit minute
// ss: two digit second, zero padded
// ZZZ: time zone, {Z,Z,Z} -> RFC 822 GMT format

Format strings for Date Formats given here: http://www.unicode.org/reports/tr35/tr35-25.html#Date_Field_Symbol_Table

Timezone string acquired from: https://stackoverflow.com/a/3299389/2022405

Adding an object to NSMutableArray causing crash

1 Answers1