dealloc called twice - iphone

I have this case where i want to pop from a view and go back to the original view.
After the button is pressed the app crashes, and the console displays EXC_BAD_ACCESS.
I run it in instruments with zombies enabled and this is what i get: link to image
as it is shown the dealloc is called twice for the same object.
instruments are pointing to an NSMutableArraywhich contains NSStrings.
can anyone help me solve this issue...
thank you.
ps: the solution provided in this question does not solve the issue.
Edit:
the array is filled with data parsed from an xml file.
-(void) grabData{
listOfNames=[[NSMutableArray alloc] init];
NSString *XMLPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"chi.xml"];
NSData *XMLData = [NSData dataWithContentsOfFile:XMLPath];
CXMLDocument *rssParser = [[[CXMLDocument alloc] initWithData:XMLData options:0 error:nil] autorelease];
NSArray *items = [rssParser nodesForXPath:#"/template/item" error:nil];
for (CXMLElement *node in items) {
int counter;
if([[[node attributeForName:#"type"] stringValue] isEqualToString:#"label"]){
for(counter = 0; counter < [node childCount]; counter++) {
[listOfNames addObject:[[node childAtIndex:counter] stringValue]];
}
}
...
and is used in this function:
-(void)setupPage{
[scroll setCanCancelContentTouches:NO];
scroll.indicatorStyle=UIScrollViewIndicatorStyleWhite;
scroll.clipsToBounds=YES;
scroll.scrollEnabled=YES;
scroll.pagingEnabled=NO;
int y=Y;
CGFloat cy=0;
int count=[listOfProperties count];
int total=count;
for(int i=0;i<count;i++){
NSString *class=[[[NSString alloc] initWithFormat:#"%#",[(NSObject *)[listOfProperties objectAtIndex:i] class]] autorelease];
if([class isEqualToString:#"textFieldCell"]){
((textFieldCell*)[listOfProperties objectAtIndex:i]).str=[listOfNames objectAtIndex:i];
[((textFieldCell*)[listOfProperties objectAtIndex:i]) setTarget:scroll];
((textFieldCell*)[listOfProperties objectAtIndex:i]).view.frame=CGRectMake(X,y,self.view.frame.size.width - remProfX,cellProfH);
[((textFieldCell*)[listOfProperties objectAtIndex:i]) setImage:[self getImageName:i maxValue:(count-1)]];
[scroll addSubview:((textFieldCell*)[listOfProperties objectAtIndex:i]).view];
}
else{
if([class isEqualToString:#"comboBoxCell"]){
((comboBoxCell*)[listOfProperties objectAtIndex:i]).str=[listOfNames objectAtIndex:i];
[((comboBoxCell*)[listOfProperties objectAtIndex:i]) setTarget:self.view];
((comboBoxCell*)[listOfProperties objectAtIndex:i]).view.frame=CGRectMake(X,y,self.view.frame.size.width - remProfX,cellProfH);
[((comboBoxCell*)[listOfProperties objectAtIndex:i]) setImage:[self getImageName:i maxValue:(count-1)]];
[scroll addSubview:((comboBoxCell*)[listOfProperties objectAtIndex:i]).view];
}
else{
if([class isEqualToString:#"dateCell"]){
((dateCell*)[listOfProperties objectAtIndex:i]).str=[listOfNames objectAtIndex:i];
[((dateCell*)[listOfProperties objectAtIndex:i]) setTarget:self.view];
((dateCell*)[listOfProperties objectAtIndex:i]).view.frame=CGRectMake(X,y,self.view.frame.size.width - remProfX,cellProfH);
[((dateCell*)[listOfProperties objectAtIndex:i]) setImage:[self getImageName:i maxValue:(count-1)]];
[scroll addSubview:((dateCell*)[listOfProperties objectAtIndex:i]).view];
}
}
...
dealloc:
- (void)dealloc {
[listOfNames release];
[listOfProperties release];
[listOfGroupNames release];
[listOfCheckBoxNames release];
[listOfCheckBoxes release];
[listOfButtons release];
[scroll release];
[super dealloc];
}

This might have happened if you created your NSArray as an autoreleased object using one of those methods:
+ array
+ arrayWithArray:
+ arrayWithContentsOfFile:
+ arrayWithContentsOfURL:
+ arrayWithObject:
+ arrayWithObjects:
+ arrayWithObjects:count:
And then in the dealloc method of your closing UIViewController you are releasing this array.
EDIT
By the way class word is reseverd it's bad to use it like you did here:
NSString *class=[[[NSString alloc] initWithFormat:#"%#",[(NSObject *)[listOfProperties objectAtIndex:i] class]] autorelease];

Related

Cannot figure out why my app crashes when I use NSKeyedArchivers / NSKeyedUnarchivers

I am developing my first iphone 'Diary' app, which uses custom 'Entry' objects that hold an NSString title, NSString text and NSDate creationDate. When I try to archive an NSMutableArray of Entry objects, and later retrieve them the next time the view loads, the app crashes. I have gone through a bunch of sample codes and examples that use NSKeyedArchivers, but still couldn't figure out why that happens. I am guessing there is a problem with the initialization of the array that holds the entries but not sure...
Here is the code, maybe you could find something that I have persistently overseen..."
//--------- Entry.m---------------
- (id) initWithCoder:(NSCoder *)aDecoder{
if ((self = [super init])) {
self.title = [[aDecoder decodeObjectForKey:#"title"] retain];
self.text = [[aDecoder decodeObjectForKey:#"text"] retain];
self.created = [[aDecoder decodeObjectForKey:#"created"] retain];
}
return self;
}
- (void) encodeWithCoder:(NSCoder *)aCoder{
[aCoder encodeObject:self.title forKey:#"title"];
[aCoder encodeObject:self.text forKey:#"text"];
[aCoder encodeObject:self.created forKey:#"created"];
}
//-------------- Diary View Controller.m
- (NSString *)dataFilePath {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
return [documentsDirectory stringByAppendingPathComponent:kFilename];
}
- (void) writeDataToArchive {
NSMutableData *data = [[NSMutableData alloc] init];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc]
initForWritingWithMutableData:data];
[archiver encodeObject:self.entriesArray forKey:#"entriesArray"];
[archiver finishEncoding];
BOOL result = [data writeToFile:[self dataFilePath] atomically:YES];
[archiver release];
[data release];
}
- (void)addItem:sender {
int count = [entriesArray count] +1;
NSString *newEntryTitle = [NSString stringWithFormat:#"Entry %d", count];
Entry *anEntry = [[Entry alloc] initWithTitle:newEntryTitle text:#"-"
created:[NSDate date]];
[entriesArray addObject:anEntry];
[self.tableView reloadData];
[anEntry release];
[self writeDataToArchive];
}
- (void)viewDidLoad
{
[super viewDidLoad];
NSString *filePath = [self dataFilePath];
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
NSData *data = [[NSMutableData alloc]
initWithContentsOfFile:[self dataFilePath]];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc]
initForReadingWithData:data];
NSMutableArray *array = [unarchiver decodeObjectForKey:#"entriesArray"];
entriesArray = [array mutableCopy];
[array release];
[unarchiver finishDecoding];
[unarchiver release];
[data release];
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:
(NSIndexPath *)indexPath
{
// ... some other stuff
NSUInteger row = indexPath.row;
Entry *entry = [entriesArray objectAtIndex:row];
cell.textLabel.text = entry.title;
return cell;
}
Thanks a lot.
When you read an array back out with NSKeyedUnarchivers you always get an unmutable copy back. You would need to declare *array as NSArray or just get rid of array all together.
entriesArray = [[unarchiver decodeObjectForKey:#"entriesArray"] mutableCopy];
And #JeremyP points out another issue. Since you didn't alloc or retain *array you should not release it.
You should not release array in viewDidLoad because you do not own it.
Please review the Cocoa memory management Rules because there are a couple of other memory management issues in your code. In particular,
self.title = [[aDecoder decodeObjectForKey:#"title"] retain];
self.text = [[aDecoder decodeObjectForKey:#"text"] retain];
self.created = [[aDecoder decodeObjectForKey:#"created"] retain];
in your initWithCoder: method all leak on the assumption the properties are retain or copy.

Incorrect decrement of the reference count of an object that is not owned at this point by the caller

Incorrect decrement of the reference count of an object that is not owned at this point by the caller on iPhone. It is happening with NSString which I clearly init and release within the for loop. I have tried to do the same as an autoreleases string but I get leaks. I assume the culprit is the stringbytrimming call. Any suggestions, by the way this does not leak, but I get the warning in build and analyze. Everything also works fine and the app does not crash.
for(int i=0;i<storyQuantity;i++) {
NSString *imageString = [[NSString alloc] init];
imageString = [[[storiesArray objectAtIndex:i] objectForKey: #"image"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; // must add trimming to remove characters
imageLoader *imageOperation = [[imageLoader alloc] initWithImageURL:imageString target:self action:#selector(didImageLoad:) number:i];
AppDelegate_iPad *appDelegate = [[UIApplication sharedApplication] delegate];
[appDelegate.queue_ addOperation:imageOperation];
[imageOperation release];
[imageString release];
}
UPDATE - added my imageLoader class, which to the best of my knowledge does not have a leak
- (id)initWithImageURL:(NSString *)url target:(id)target action:(SEL)action number:(int)number {
if(self = [super init]) {
_action = action;
_target = target;
_number = number;
if(url == nil) {
return nil;
} else {
_imgURL = [[NSURL alloc] initWithString:[url copy]];
}
}
return self;
}
- (id)main {
NSAutoreleasePool *pool = [NSAutoreleasePool new];
if ([self isCancelled]) {
NSLog(#"OPERATION CANCELLED");
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[pool drain];
return nil;
} else {
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
NSData *imgData = [[NSData alloc] initWithContentsOfURL:_imgURL];
UIImage *image = [[UIImage alloc] initWithData:imgData];
[imgData release];
if ([self isCancelled]) {
NSLog(#"OPERATION CANCELLED");
[image release];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[pool drain];
return nil;
} else {
NSNumber *tempNumber = [NSNumber numberWithInt:_number];
NSDictionary *tempDict = [NSDictionary dictionaryWithObjectsAndKeys:tempNumber, #"number", image, #"image", nil];
[image release];
if([_target respondsToSelector:_action])
[_target performSelectorOnMainThread:_action withObject:tempDict waitUntilDone:NO];
}
}
[pool drain];
return nil;
}
- (void)dealloc {
[_imgURL release];
[super dealloc];
}
Since you are reassigning the imageString variable, the reference to the original object is lost. Why allocate an empty string anyway? Just change the code to
NSString *imageString = [[[storiesArray objectAtIndex:i] objectForKey: #"image"]
stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
and remove the [imageString release] and you're good to go.
Don't track reference counts as a way into understanding memory management. It's only going to confuse you. Things manipulate your objects' reference counts from deep in the framework, and if you watch those numbers jump around for (apparently) no reason, you'll just go insane and post a series of increasingly crazy questions here, which we'll then have to deal with. Believe me--we've seen it before.
So just ignore the reference count number, and make sure you're retaining and releasing objects properly.

Memory Leak related

i am working on a fishing app these days and i am getting a memory leak problem
-(void)requestFinished:(ASIFormDataRequest *) request {
if(hud != nil){
[hud show:NO];
[hud release];
hud = nil;
}
isLoading = NO;
self.responseText = [request responseString];
[self parseXml]; //I am getting leak here
if ( [self.responseText hasPrefix:#"<result>"]) {
UIAlertView *info = [[[UIAlertView alloc] initWithTitle:#" " message:#"Limited Internet access, please find a stronger signal in the area" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil]autorelease];
[info show];
}
if (!isRefreshButtonClicked) {
[UIAccelerometer sharedAccelerometer].delegate = self;
[NSThread detachNewThreadSelector:#selector(parseXml) toTarget:self withObject:nil];
} }
This is my function...
-(void) parseXml
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
_fishes = [[fishes parseXml:self.responseText] retain];
[self performSelectorOnMainThread:#selector(parseXmlDone) withObject:nil waitUntilDone:YES];
[pool release];
Here _fishes is an array which is getting a value from a array return type function.....and here is that function...
+(NSMutableArray *)parseXml:(NSString *)xmlString {
//xmlString = [xmlString stringByReplacingOccurrencesOfString:#"&" withString:#""];
const char *cString = [xmlString UTF8String];
NSMutableArray *fishes = [NSMutableArray array];
NSData *xmlData = [NSData dataWithBytes:cString length:strlen(cString)];
NSError *error;
GDataXMLDocument *doc = [[GDataXMLDocument alloc]initWithData:xmlData options:0 error:&error];
if (doc == nil) { return nil; }
//parseXml
NSArray *_fishes = [doc.rootElement elementsForName:#"fishery"];
for (GDataXMLElement *_fish in _fishes) {
NSMutableDictionary *fish = [NSMutableDictionary dictionary];
NSArray *ids = [_fish elementsForName:#"id"];
if ([ids count]>0) {
GDataXMLElement *firstId = (GDataXMLElement *)[ids objectAtIndex:0];
[fish setValue:firstId.stringValue forKey:#"id"];
} else continue;
NSArray *names = [_fish elementsForName:#"name"];
if ([names count]>0) {
GDataXMLElement *firstName = (GDataXMLElement *)[names objectAtIndex:0];
[fish setValue:firstName.stringValue forKey:#"name"];...........
........
else continue;
NSArray *distances = [_fish elementsForName:#"distance"];
if ([distances count]>0) {
GDataXMLElement *distance = (GDataXMLElement *)[distances objectAtIndex:0];
[fish setValue:distance.stringValue forKey:#"distance"];
}else continue;
[fishes addObject:fish];
}
[doc release];
return fishes;
}
#end
I hope u guys will understand my problem...thanx
In -parseXml,
_fishes = [[fishes parseXml:self.responseText] retain];
will leak any previous object _fishes was pointing to in case -parseXml is sent more than once. You could use a retain property instead of an instance variable, or a setter method that releases the previous object, or release the previous object before assigning a new (retained) object to _fishes.

giving nil while accessing the nsmutable array

i am parsing a json object and storing the song objects in songs, a nsmutable array.
while am displaying the image of the song i.e. while accessing the object from the array its giving all values nil in that object.
in the following code in setSongsScrollView method, in for loop while accessing the song object from songs array its showing nill in the debugger and crashing with error EXEBadacess.But the count of that array is giving correct.
can any body help me out please
- (void)viewWillAppear:(BOOL)animated{
[super viewDidLoad];
[self parsingTheStation];
[self load_images];
[self setSongsScrollView];
}
/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/
- (void)parsingTheStation{
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:#"http:...."]];
NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSString *jsonString = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
NSData *jsonData = [jsonString dataUsingEncoding:NSUTF32BigEndianStringEncoding];
NSDictionary *dictionary = [[CJSONDeserializer deserializer] deserializeAsDictionary:jsonData error:nil];
songs =[[NSMutableArray alloc]init];
NSArray *songObjects = [dictionary objectForKey:#"songs"];
for(NSDictionary *s in songObjects){
aSong = [[Song alloc] init];
aSong.artist = [s objectForKey:#"by"];
aSong.genre = [s objectForKey:#"genre"];
aSong.cover = [s objectForKey:#"cover"];
aSong.song_id = [s objectForKey:#"id"];
aSong.rank = [s objectForKey:#"rank"];
aSong.title = [s objectForKey:#"title"];
aSong.link = [s objectForKey:#"link"];
[songs addObject:aSong];
[aSong release];
}
NSLog(#"total number of songs is : %d",[songs count]);
}
-(void)setSongsScrollView {
songsContainer = [[UIScrollView alloc]init];
int songsCount = [self.songs count];
//totla no. of songs we get +4
int tSongs = songsCount+4;
int n = sqrt(tSongs);
int p = n,q = n;
int remSongs = tSongs-(n*n);
if(remSongs >= n){
q = q+(remSongs/n);
if((remSongs%n)>0)
q++;
}else q++;
for(int i=0;q>p;i++){
q--;
p++;
}
NSLog(#"total songs..%d",tSongs);
NSLog(#"total rows..%d",q);
NSLog(#"total columns..%d",p);
songsContainer.contentSize = CGSizeMake(120*q, 120*p);
int x =0, y=240, col=1;
for(int i=0;i<songsCount;i++){
CGRect imgFrame = CGRectMake(x, y, 118, 118);
NSLog(#"songs conunt ...%d",[songs count]);
Song *thesong = [[Song alloc]init];
thesong = [self.songs objectAtIndex:i];
NSString *filename = [NSString stringWithFormat:#"%#/%#", [LazyImageView dataPath], [thesong.cover lastPathComponent]];
UIImageView *tempImg = [[UIImageView alloc] initWithImage:[UIImage imageWithContentsOfFile:filename]];
tempImg.tag = i;
tempImg.frame = imgFrame;
[songsContainer addSubview:tempImg];
[tempImg release];
[thesong release];
y += 120;
if(y>=(120*p)){
NSLog(#"total y..%d",y);
col++;
x += 120;
if(col>=3)
y=0;
else
y=240;
}
}
NSLog(#"total y..%d",y);
NSLog(#"content size..%d,%d",120*q,120*p);
}
-(void)load_images{
for(int i=0;i<[songs count];i++){
Song *rsong = [[Song alloc]init];
rsong = [self.songs objectAtIndex:i];
lazyBigImg = [[LazyImageView alloc] init];
NSURL* url = [NSURL URLWithString:rsong.cover];
[lazyBigImg loadImageFromURL:url];
[lazyBigImg release];
[rsong release];
}
}
/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[songs release];
[lazyBigImg release];
[onAirBtn release];
[chartsBtn release];
[dealsBtn release];
[searchBtn release];
[stNameLbl release];
[aSong release];
[songsContainer release];
[super dealloc];
}
#end
Marcel has basically got the right answer but I think a little more explanation is needed. Look at the following lines from setSongsScrollView:
Song *thesong = [[Song alloc]init];
The above line allocates a new Song that you own and assigns a reference to it to thesong
thesong = [self.songs objectAtIndex:i];
The above line replaces that reference with a new reference to a song from the array that you don't own. Remember that: you do not own the song referenced by thesong now. There are now no more references left to the object you just allocated, but you still own it. The object has therefore leaked.
NSString *filename = [NSString stringWithFormat:#"%#/%#", [LazyImageView dataPath], [thesong.cover lastPathComponent]];
Use stringByAppendingPathComponent: to build file paths, not stringWithFormat:.
UIImageView *tempImg = [[UIImageView alloc] initWithImage:[UIImage imageWithContentsOfFile:filename]];
tempImg.tag = i;
tempImg.frame = imgFrame;
[songsContainer addSubview:tempImg];
[tempImg release];
[thesong release];
The last line in the above sequence releases the object referenced by thesong. As noted above, you do not own that object. You must not release it, but you have anyway. This means that, at some point, may be now, maybe later, the object will be deallocated while something (probably the array) still thinks it has a valid reference. That's what causes the crash.
-(void)load_images{
for(int i=0;i<[songs count];i++){
Song *rsong = [[Song alloc]init];
rsong = [self.songs objectAtIndex:i];
lazyBigImg = [[LazyImageView alloc] init];
NSURL* url = [NSURL URLWithString:rsong.cover];
[lazyBigImg loadImageFromURL:url];
[lazyBigImg release];
[rsong release];
}
}
The above method contains exactly the same error.
You're creating a new Song instance (thesong), then assign this very instance to a song presumably already in the array. That makes no sense at all and is probably responsible for the memory error.
You shouldn't need to be creating new Songs if they are already in the array. Instead:
Song *thesong = [self.songs objectAtIndex:i];
Also look into using the Objective-C 2.0 for-each loop syntax.

EXC_BAD_ACCESS in viewDidLoad of FlipsideViewController

I'm trying to display some data on the flip side view of a utility template application but the application aborts at the end of viewDidLoad method. I'm very new to iOS and could do with a bit of guidance.
[super viewDidLoad];
self.view.backgroundColor = [UIColor viewFlipsideBackgroundColor];
NSString *thePath = [[NSBundle mainBundle] pathForResource:#"SavedData"ofType:#"plist"];
NSMutableDictionary *tempRootDictionary;
NSMutableArray *tempMutableArray;
if (thePath && (tempRootDictionary = [NSMutableDictionary dictionaryWithContentsOfFile:thePath])) {
NSArray *keys = [tempRootDictionary allKeys];
int keysCount = [keys count];
tempMutableArray = [NSMutableArray arrayWithCapacity:keysCount];
for (int i=0; i<keysCount; i++) {
NSDictionary *dictionary = [tempRootDictionary objectForKey:[keys objectAtIndex:i]];
MyModelObject *aModelObject = [[MyModelObject alloc] init];
[aModelObject setName:[dictionary objectForKey:#"name"]];
[aModelObject setContext:[dictionary objectForKey:#"context"]];
[aModelObject setUsername:[dictionary objectForKey:#"username"]];
[aModelObject setPassword:[dictionary objectForKey:#"password"]];
[tempMutableArray addObject:aModelObject];
[aModelObject release];
[dictionary release];
}
} else {
return;
}
Help would be really appreciated,
Many thanks...
The only obvious problem I see in the code posted is this:
[dictionary release];
On the line that you set dictionary, you are only getting a reference to the object in tempRootDictionary and not a new alloc'd instance of it. So don't release it. Remove that line.