Question

im new with objective-c. I have problem with memory leaking when developing iphone app. Leaking utility in Xcode shows that leaking problem with ‘combArr’->’results’ object. There is my function which parsing json from url and returns NSArray:

- (NSArray *)getListing2:(NSString *)item
                         from:(int)country {
    //sending post request with some params
    NSString *post = [@"product=" stringByAppendingString:item];
    NSString *countryStr = [NSString stringWithFormat:@"&country=%d", country];
    post = [post stringByAppendingString:countryStr];
    NSData *postData = [post dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
    NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]];

    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];

    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    NSString *url = [prefs objectForKey:@"urlToApi"];
    url = [url stringByAppendingString:@"/get-items/"];
    [request setURL:[NSURL URLWithString:url]];
    [request setHTTPMethod:@"POST"];
    [request setValue:postLength forHTTPHeaderField:@"Content-Length"];
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [request setHTTPBody:postData];
    NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    [request release];

    //receiving json
    NSString *jsonString = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
    SBJsonParser *json = [[SBJsonParser alloc] init];
    NSError *error = nil;
    //parsing json to nsdictionary
    NSDictionary *results = [[NSDictionary alloc] initWithDictionary:[json objectWithString:jsonString error:&error]];
    [json release];
    [jsonString release];

    //generate array of items
    NSMutableArray *listOfItems = [[NSMutableArray alloc] init];
    for (int i = 0; i < [[results objectForKey:@"data"] count]; i++) {
        [listOfItems addObject:[[results objectForKey:@"data"] objectForKey:[NSString stringWithFormat:@"%d", i]]];
    }

    //saving items array and count info object into one array
    NSArray  * returnArr = [[[NSArray arrayWithObjects:listOfItems, [results valueForKey:@"count_info"], nil] retain] autorelease];

    [listOfItems release];
    [results release];

    return returnArr;
}

And i executing this function here:

myApi *itemsApi = [[myApi alloc] init];
NSArray  *combArr = [[izdApi getListing2:item from:countryId] retain];
[itemsApi release];
listOfItems = [[combArr objectAtIndex:0] retain];
if([listOfItems count] > 0){
    priceArr = [[combArr objectAtIndex:1] retain];
}
else{
    totalCount = 0;
}
[combArr release];

Thank you for helping

Answer 1

Every time you allocate memory, you must release it. (alloc, copy, retain).
You are releasing myApi, not itemsApi. Try this…

myApi *itemsApi = [[itemsApi alloc] init];
NSArray  *combArr = [[izdApi getListing2:item from:countryId] retain];
[itemsApi release];
listOfItems = [[combArr objectAtIndex:0] retain];
if([listOfItems count] > 0){
priceArr = [[combArr objectAtIndex:1] retain];
}
else{
    totalCount = 0;
}
[combArr release];

If you are using Xcode 4, Try turning on ARC. In short, ARC handles the releasing of all memory. A little burden off your shoulders and one less thing for you to worry about.