Memory Management / Releasing Objects

[svveet]

Originally Posted by BrianSlick

// declare array
[self setFieldDataArray:[[NSMutableArray alloc] init]];
[self setSectionArray:[[NSMutableArray alloc] init]];

These are leaks. Never do alloc/init in the same line as you assign a property. It should be three lines, like this:

NSMutableArray *fieldArray = [[NSMutableArray alloc] init];
[self setFieldDataArray: fieldArray];
[fieldArray release], fieldArray = nil;

// name 
NSString *trackName = [[self trackDict] objectForKey:kNameKey];
if (trackName == nil) 
   trackName = @"";
[[self fieldDataArray] addObject:trackName];
[self setNameText:trackName];
[trackName release];

I'm going to say that's the problem. trackName is autoreleased.


By the way, comment "when i click "back button" on the navigationcontroller" would have been a useful piece of information before. That's most likely when the autorelease pool is getting drained. I thought you meant you were literally crashing at the aforementioned line of code.

I have fixed the things you said, but when i try to release trackDictionary, it still crashes when i click "back button". very weird.

but if i dont release it, its fine.

[BrianSlick]

Well, I don't know what else to tell you. Probably time for you to do to a thorough review of your code, line by line, and double check all of the little things we've talked about in this thread. Release if you did an alloc/init, don't if you didn't, etc.

I just don't see how trackDictionary can be an autoreleased object, so I'm almost positive the problem is somewhere else.

[eddietr]

Originally Posted by svveet

I have fixed the things you said, but when i try to release trackDictionary, it still crashes when i click "back button". very weird.

but if i dont release it, its fine.

So I don't think the problem is that you are over-releasing the dictionary. The problem is you are over-releasing items in the dictionary. By not releasing the dictionary itself, you are just masking the problem.

For example look at this:

NSMutableArray *triparray = [[self trackDict] objectForKey:kTripKey];
		[self setCurrentTrackTripArray:triparray];
		[triparray release]; // You shouldn't be doing this.

You don't want to be releasing triparray there. There may be other cases of this as well, so if you clean those up then you should be able to release the dictionary after setTrackDict, which is the right thing to do.

Hope that helps. If not, please post the current version of the code including all the new changes you've incorporated.

[svveet]

Originally Posted by eddietr

So I don't think the problem is that you are over-releasing the dictionary. The problem is you are over-releasing items in the dictionary. By not releasing the dictionary itself, you are just masking the problem.

For example look at this:

NSMutableArray *triparray = [[self trackDict] objectForKey:kTripKey];
		[self setCurrentTrackTripArray:triparray];
		[triparray release]; // You shouldn't be doing this.

You don't want to be releasing triparray there. There may be other cases of this as well, so if you clean those up then you should be able to release the dictionary after setTrackDict, which is the right thing to do.

Hope that helps. If not, please post the current version of the code including all the new changes you've incorporated.

Yes you are absolutely right! you have fixed my problem. thanks alot for all.
triparray should be autoreleased, isnt it.

[eddietr]

Originally Posted by svveet

Yes you are absolutely right! you have fixed my problem. thanks alot for all.
triparray should be autoreleased, isnt it.

Well, it's not really autoreleased here, because objectForKey doesn't retain it. So there is no need to autorelease it. And no need for you to release it either.

[svveet]

I have another problem releasing objects issue, its bothering me.

when i try to release an NSMutableArray object, if i release it, it crashes.

I just want to know if i added NSMutableArray to another NSMutableArray, do i release both of them? or just 1?

Here is the code:

if (isNewTrip) {
		NSMutableArray *emptyarray2 = [[NSMutableArray alloc] init]; 
		[self setRecordXYArray:emptyarray2];
		[self setRecordShopArray:emptyarray2];
		[emptyarray2 release];   // somehow when i tried to release emptyarray2, it crashes. 
	}
	
	NSMutableArray *singleXYPoint = [[NSMutableArray alloc] init]; 
	NSNumber *pLat = [[NSNumber alloc]initWithDouble:shopLatitude];
	NSNumber *pLong = [[NSNumber alloc]initWithDouble:shopLongtitude];
	
	// Timestamp
	NSDate *date = [NSDate date];
	NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init]  autorelease];
	[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
	[dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
	[dateFormatter stringFromDate:date];
	[dateFormatter setDateFormat:@"dd/MM/yyyy H:m:ss"];
	NSString *testDate = [dateFormatter stringFromDate:[NSDate date]];
	
	NSNumber *horAccuracy = [[NSNumber alloc]initWithFloat:-1.0];
	
	[singleXYPoint addObject:pLat];
	[singleXYPoint addObject:pLong];
	[singleXYPoint addObject:testDate];
	[singleXYPoint addObject:date];
	[singleXYPoint addObject:horAccuracy];
	
	[recordXYArray addObject:singleXYPoint]; 

	[singleXYPoint release];

[BrianSlick]

You are adding the same emptyarray2 to two different properties. I'm guessing that you will want a separate array - emptyarray3? - for each one.

[bytor99999]

I found on iTunes, the Stanford University iPhone class videos to be very helpful. They have a great one which deals with memory and releasing object that really cleared up a lot for me.

If you go to iTunes, I think a search on Stanford and iPhone should return those videos.

Mark