I currently have this code but it leaks because I don't know how to release feed parser object this many times, so I need help with memory management or some other way to feed multiple feeds with it.
Code:
for (NSString *imePredmeta in [Data variables].mojiPredmeti) {
NSString *link = [[Data variables].rss objectForKey: imePredmeta];
NSURL *feedURL = [NSURL URLWithString: link];
feedParser = [[MWFeedParser alloc] initWithFeedURL:feedURL];
feedParser.delegate = self;
feedParser.feedParseType = ParseTypeFull; // Parse feed info and all items
feedParser.connectionType = ConnectionTypeAsynchronously;
[feedParser parse];
}
Dealloc:
- (void)dealloc {
[formatter release];
[parsedItems release];
[itemsToDisplay release];
[feedParser release];
[super dealloc];
}
And initWithFeedUrl from MWFeedParser code is:
- (id)initWithFeedURL:(NSURL *)feedURL {
if ((self = [self init])) {
// Check if an string was passed as old init asked for NSString not NSURL
if ([feedURL isKindOfClass:[NSString class]]) {
feedURL = [NSURL URLWithString:(NSString *)feedURL];
}
// Remember url
self.url = feedURL;
}
return self;
}
The best way would be to add them to an array, and then in dealloc release that array.
// declare an iVar in your header file
NSMutableArray *feeds;
// instantiate the array, but release it first as you may call your method more
// than once
if (feeds) {
[feeds release];
}
feeds = [[NSMutableArray alloc] init];
for (NSString *imePredmeta in [Data variables].mojiPredmeti) {
...
// after calling parse on the feed, add it to the array and then release it.
// Objects added to an array are retained by the array so this is safe
[feedParser parse];
[feeds addObject:feedParser]; // <-- Add parser to array
[feedParser release]; // <-- Release parser
}
// then in your dealloc simply release the array, which will in-turn release all
// the parser objects it contains
- (void)dealloc {
[formatter release];
[parsedItems release];
[itemsToDisplay release];
[feeds release]; // <-- Release feeds array
// I've removed the call to release feedParser as it's already been released
[super dealloc];
}
Related
I have a little problem with memory management in my iOS App. I load an XML and set all Values in this XML to Spezific Objects. Now my problem is when i reload the XML every 15 - 20 reloads of this XML my app Crash on Parsing here is a sample of my parser.
EDIT: Here ist the ERROR when NSZombie is Enabled if NSZombie is disabled I didn't get an ERROR message.
-[CFNumber retain]: message sent to deallocated instance
thanks for help.
EDIT:
the beginning of my Code:
- (id)init
{
self = [super init];
if (self) {
TheObjects *theObjects = [[TheObjects alloc] init];
[self parse];
}
return self;
}
- (void) reload{
reload = YES;
TheObjects *theTmpObjects = [[TheObjects alloc] init];
[self parse];
}
- (void)parse{
for (id xmlOBject in xmlObjects){
MyObject *object = [[MyObject alloc] init];
object.number1 = [NSNumber numberWithInt:1];
object.number2 = [NSNumber numberWithInt:2];
object.number3 = [NSNumber numberWithInt:3];
if (reload)
[theTmpObjects.objects addObject:object];
else
[theObjects.objects addObject:object];
[object release];
}
//later in my code
TheObjects *localTheTmpObjects = nil;
if (reload){
localTheTmpObjects = theObjects;
theObjects = theTmpObjects;
}
if ([delegate respondsToSelector:#selector(finished:)]){
[delegate performSelector:#selector(finished:) withObject:theObjects];
}
if(reload)
[localTheTmpObjects release];
}
remove the line [localTheTmpObjects release]
you don't own the object
at the end, call the `[localTheTmpObjects autorelease];`
this is because if you release array, all its objects are released and hence may cause crash, when your array may in use
- (id)init
{
self = [super init];
if (self) {
TheObjects *obbjects = [[TheObjects alloc] init];
theObjects = objects;
[objects releas];
[self parse];
}
return self;
}
- (void) reload{
reload = YES;
TheObjects *obbjects = [[TheObjects alloc] init];
thetmpObjects = objects;
[objects releas]; [self parse];
}
- (void)parse{
for (id xmlOBject in xmlObjects){
MyObject *object = [[MyObject alloc] init];
object.number1 = [NSNumber numberWithInt:1];
object.number2 = [NSNumber numberWithInt:2];
object.number3 = [NSNumber numberWithInt:3];
if (reload)
[theTmpObjects.objects addObject:object];
else
[theObjects.objects addObject:object];
[object release];
}
//later in my code
TheObjects *localTheTmpObjects = nil;
if (reload){
localTheTmpObjects = theObjects;
theObjects = theTmpObjects;
}
if ([delegate respondsToSelector:#selector(finished:)]){
[delegate performSelector:#selector(finished:) withObject:theObjects];
}
}
my question depends on my other question
NSMutableArray vs NSArray
i have created a navigationController and load a TableView inside with data from the other question. Now a get a detailview and get new data from xml, so i copy my methods and modifide them.
but it is the same stucture, i does not change a lot.
But now i get the same error.
i have in detailview.h
NSMutableArray *seminareArray;
and
#property (nonatomic, retain) NSMutableArray *seminareArray;
in detailview.m
#synthesize SeminareListeTabelle, selectedSeminar, seminareArray, receivedData;
i add this code
seminareArray = [[NSMutableArray alloc] init];
self.seminareArray = [NSMutableArray arrayWithCapacity:10];
before i add the data. and i get the error here
cell.textLabel.text = [seminareArray objectAtIndex:row];
EXC_BAD_ACCESS again some type problem
i add data to array like this
if([elementName isEqualToString:#"seminar"])
{
//NSLog(#"%#", [attributeDict objectForKey:#"name"]);
NSString *seminarName = [NSString stringWithFormat:#"%#", [attributeDict objectForKey:#"name"]];
[seminareArray addObject:seminarName];
[seminarName release];
}
the array is filled with data, but after tableView reload, i get this error.
//
// SeminareListingView.m
// Seminar App2
//
// Created by Alexander Frischbutter on 05.07.11.
// Copyright 2011 __MyCompanyName__. All rights reserved.
//
#import "SeminareListingView.h"
//#import "SeminareView.h"
#implementation SeminareListingView
#synthesize SeminareListeTabelle, selectedSeminar, seminareArray, receivedData;
- (void) parseData:(NSString *)url
{
if(receivedData)
{
receivedData = nil;
}
NSLog(#"Parsing... url: %#", url);
NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:[NSString stringWithFormat:#"%#", url]] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if(theConnection)
{
receivedData = [[NSMutableData data] retain];
}
else
{
//label.text = #"XML nicht geladen";
NSLog(#"XML nicht gefunden");
}
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)dealloc
{
[super dealloc];
}
- (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.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
SeminareListeTabelle = [[UITableView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame] style:UITableViewStylePlain];
SeminareListeTabelle.delegate = self;
SeminareListeTabelle.dataSource = self;
SeminareListeTabelle.autoresizesSubviews = YES;
seminareArray = [[NSMutableArray alloc] init];
self.seminareArray = [NSMutableArray arrayWithCapacity:10];
[self parseData:[NSString stringWithFormat:#"http://akademie.kunden.fincha.com/semapp/sem_kat_arbtechnik.xml", selectedSeminar]];
self.navigationItem.title = [NSString stringWithFormat:#"%#", selectedSeminar];
self.view = SeminareListeTabelle;
// Do any additional setup after loading the view from its nib.
}
- (void)startParsingData
{
NSLog(#"Parsing started");
NSXMLParser *dataParser = [[NSXMLParser alloc] initWithData:receivedData];
dataParser.delegate = self;
[dataParser parse];
[dataParser release];
[receivedData release];
NSLog(#"Received Data in seminareArray");
/*
for(int i = 0; i < [seminareArray count]; i++)
{
NSLog(#"%d is %#", i, [seminareArray objectAtIndex:i]);
//NSLog(#"Count %d", [kategorienArray count]);
}
*/
//[seminareArray release];
NSLog(#"Reload data in TableView");
[self.SeminareListeTabelle reloadData];
NSLog(#"Data reloaded");
}
- (void)viewDidUnload
{
//[seminareArray release];
//[SeminareListeTabelle release];
NSLog(#"Vew unloaded");
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *SimpleTableIdentifier = #"SimpleTableIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: SimpleTableIdentifier];
if (cell == nil) { cell = [[[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:SimpleTableIdentifier] autorelease];
}
if([seminareArray count] != 0)
{
NSLog(#"Adding data to cell");
NSUInteger row = [indexPath row];
//cell.textLabel.text = [NSString stringWithFormat:#"bla, %d", row]; //[seminareArray objectAtIndex:row];
cell.textLabel.text = [seminareArray objectAtIndex:row];
NSLog(#"Added data to cell");
}
return cell;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//NSLog(#"Count %d", [self.seminareArray count]);
return [seminareArray count];
}
-(NSInteger) tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 0;
}
//Anzeige mit Seminaren öffnen bei Click auf die Zeile
-(void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
//gehe zurück zum ersten View
//NSLog(#"Received Data in seminareArray");
[[self navigationController] popViewControllerAnimated:YES];
}
- (void)connection:(NSURLConnection *)connection didReceiveResonse:(NSURLResponse *)response
{
[receivedData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
if(receivedData)
{
[receivedData appendData:data];
}
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
[connection release];
[receivedData release];
//label.text = #"Connection failed";
NSLog(#"Verbindung fehlgeschlagen!");
//[[self navigationController] popViewControllerAnimated:YES];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
[self startParsingData];
[connection release];
}
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
//NSLog(#"Parser was called. Element: %#", elementName);
if([elementName isEqualToString:#"seminar"])
{
//NSLog(#"%#", [attributeDict objectForKey:#"name"]);
NSString *seminarName = [NSString stringWithFormat:#"%#", [attributeDict objectForKey:#"name"]];
[seminareArray addObject:seminarName];
[seminarName release];
}
}
- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
{
NSLog(#"Parse Error %#", parseError);
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
#end
The problem stems from this code:
seminareArray = [[NSMutableArray alloc] init]; // owned
seminareArray = [NSMutableArray arrayWithCapacity:10]; // autoreleased
You're first initializing the semiareArray as an owned object, but then are re-setting it as an autoreleased object.
Meaning, it will be released after the run-loop terminates.
Remove the second (autoreleased) statement but keep the first, and everything should work fine.
The reason why you're getting the EXC_BAD_ACCESS error is because the seminareArray object is released at some point before it being used again.
Additionally, try to debug your
cell.textLabel.text = [seminareArray objectAtIndex:row];
Try setting it as id var = [seminareArray objectAtIndex:row]; and then setting cell.textLabel.text = var; This will tell you if the error occurs due to array being dealloc'd too early, or improper cell/textLabel.
Updated:
There's an additional problem is with the code:
NSString *seminarName = [NSString stringWithFormat:#"%#", [attributeDict objectForKey:#"name"]];
[seminareArray addObject:seminarName];
[seminarName release]; // <--
You're creating an auto-released object seminarName, which technically has retain count 0. You're adding it to the semiareArray, which ups the object retain count to 1. Then you're releasing it again. Which causes it to be dealloc'd at runtime. The problem is that when you're assigning the value to the textLabel, the object no longer exists.
Solution: remove the [seminarName release]; Don't worry about releasing the seminarName, since it's auto-released, it will be released when the array is dealloc'd, or when the object it removed from the array.
David's answer is correct but I would advice reading up on your memory management.
If you are synthesizing properties then it is a lot easier to use the getters and setters and let them do the memory management for you. The exception being in your init/dealloc methods where you should try to directly use the ivars to avoid any potential side effects of using the getters/setters.
With the two lines david highlighted
seminareArray = [[NSMutableArray alloc] init]; // owned
seminareArray = [NSMutableArray arrayWithCapacity:10]; // autoreleased
You could potentially use either if the memory management was done correctly.
The first line on its own is correct as it creates an instance of NSMutableArray with a retain count of +1 then assigns it straight to the ivar.
Then as David pointed out the second line replaces this with an autoreleased NSMutableArray so this line is superflous and crashes your program. The method arrayWithCapacity: is not simply setting the capacity of the array it is giving you a new autoreleased array.
If you wanted to use an autoreleased NSMutableArray then you would need to use the setter either with dot notation of passing a message:
self.seminareArray = [NSMutableArray arrayWithCapactiy:10];
OR
[self setSeminareArray:[NSMutableArray arrayWithCapcity:10]];
By simply referencing things straight to seminareArray you are avoiding the getters/setters you synthesized and therefore are responsible for all of your memory management.
A hint at a memory leak:
self.seminareArray = [[NSMutableArray alloc] init];
this will leak memory because seminare is declared as retained property:
#property (nonatomic, retain) NSMutableArray *seminareArray;
This is not, anyway, the cause of your other issue.
The error you are having is caused by row being greater that the count of your array. So either you don't add sufficient objects to the array, or you try to use an incorrect value for row. Inspect that line with a debugger and ensure that row never goes beyond [seminare count]; you will find out easily why it happens.
I have an app that uses a segmentedControl. First item is an "All" item, where the rest is created from an array based on result from webservice. When "All" is selected I want to request all the request.
How can I go about this,
NSArray *urls = [NSArray arrayWithObjects:#"http://service/group/1/",
#"http://service/group/2/", nil];
I want to collect all result from the calls into a collection and display it in a UITableView when the "All" item is selected and probably in viewDidLoad.
For the other segments only one of the request is issued and callback with an array that then is used in:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
I have tried to look at this example for making the request from the array MultipleDownloads
Thanks,
The method in my viewController to initiate the multiple download:
- (void)requestChildrenInBackground {
queue = [[NSOperationQueue alloc] init];
//Todo remove hard coded and get from previous request respons
NSArray *urls = [NSArray arrayWithObjects: #"http://service/1/children",
#"http://service/2/children",
#"http://service/3/children", nil];
NSLog(#"%#", urls);
for (NSString * url in urls)
{
GetSchedule *operation =
[GetSchedule urlDownloaderWithUrlString:url];
[queue addOperation:operation];
}
}
This is how the multiple request gets handled:
#import "GetSchedule.h"
#import "JSON.h"
#import "Authentication.h"
#import "AttendanceReportViewController.h"
#interface GetSchedule ()
- (void)finish;
#end
#implementation GetSchedule
#synthesize appDelegate;
#synthesize username;
#synthesize password;
#synthesize authenticationString;
#synthesize encodedLoginData;
#synthesize schedulesArray;
#synthesize url = _url;
#synthesize statusCode = _statusCode;
#synthesize data = _data;
#synthesize error = _error;
#synthesize isExecuting = _isExecuting;
#synthesize isFinished = _isFinished;
+ (id)urlDownloaderWithUrlString:(NSString *)urlString {
NSURL * url = [NSURL URLWithString:urlString];
GetSchedule *operation = [[self alloc] initWithUrl:url];
return [operation autorelease];
}
- (id)initWithUrl:(NSURL *)url {
self = [super init];
if (self == nil)
return nil;
_url = [url copy];
_isExecuting = NO;
_isFinished = NO;
return self;
}
- (void)dealloc
{
[username release];
[password release];
[encodedLoginData release];
[_url release];
[_connection release];
[_data release];
[_error release];
[super dealloc];
}
- (BOOL)isConcurrent
{
return YES;
}
- (void)start
{
if (![NSThread isMainThread])
{
[self performSelectorOnMainThread:#selector(start) withObject:nil waitUntilDone:NO];
return;
}
self.username = appDelegate.username;
self.password = appDelegate.password;
Authentication *auth = [[Authentication alloc] init];
authenticationString = (NSMutableString*)[#"" stringByAppendingFormat:#"%#:%#", username, password];
self.encodedLoginData = [auth encodedAuthentication:authenticationString];
[auth release];
NSLog(#"operation for <%#> started.", _url);
[self willChangeValueForKey:#"isExecuting"];
_isExecuting = YES;
[self didChangeValueForKey:#"isExecuting"];
// Setup up the request with the url
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]
initWithURL:_url];
[request setHTTPMethod:#"GET"];
[request setValue:[NSString stringWithFormat:#"Basic %#", encodedLoginData] forHTTPHeaderField:#"Authorization"];
_connection = [[NSURLConnection alloc] initWithRequest:request
delegate:self];
if (_connection == nil)
[self finish];
else {
_data = [[NSMutableData alloc] init];
}
}
- (void)finish
{
NSLog(#"operation for <%#> finished. "
#"status code: %d, error: %#, data size: %u",
_url, _statusCode, _error, [_data length]);
[_connection release];
_connection = nil;
[self willChangeValueForKey:#"isExecuting"];
[self willChangeValueForKey:#"isFinished"];
_isExecuting = NO;
_isFinished = YES;
[self didChangeValueForKey:#"isExecuting"];
[self didChangeValueForKey:#"isFinished"];
}
#pragma mark -
#pragma mark NSURLConnection delegate
- (void)connection:(NSURLConnection *)connection
didReceiveResponse:(NSURLResponse *)response
{
//[_data release];
//_data = [[NSMutableData alloc] init];
[_data setLength:0];
NSHTTPURLResponse * httpResponse = (NSHTTPURLResponse *)response;
_statusCode = [httpResponse statusCode];
}
- (void)connection:(NSURLConnection *)connection
didReceiveData:(NSData *)data
{
[_data appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// Parse the responseData of json objects retrieved from the service
SBJSON *parser = [[SBJSON alloc] init];
NSString *jsonString = [[NSString alloc] initWithData:_data encoding:NSUTF8StringEncoding];
NSDictionary *jsonData = [parser objectWithString:jsonString error:nil];
NSMutableArray *array = [jsonData objectForKey:#"Children"];
schedulesArray = [NSMutableArray array];
[schedulesArray addObject:array];
// Callback to AttendanceReportViewController that the responseData finished loading
[attendanceReportViewController loadSchedule];
[self finish];
}
- (void)connection:(NSURLConnection *)connection
didFailWithError:(NSError *)error
{
_error = [error copy];
[self finish];
}
#end
When all data is received I want to call back to my ViewController and get an array with all data from all request made.
Create a downloader
Create a downloader class using NSURLConnection.
Keep a member variable called downloaderObjectId.
Write a delegate method for this object. This method will pass the downloaded data and downloaderObjectId back to the delegate.
In the delegate.
Create multiple downloader objects(As per your ncessity) with unique value for the downloaderObjectId.
Store these objects in a NSMutableDictionary
Key for each object will be downloaderObjectId. so that when the delegate method is called after download you take the exact object back from the NSMutableDictionary using this key.
Main point.
Each time delegate is called. You should remove the object from dictionary(The object who is done with the download and called his delgate. You can identify this object by the key downloaderObjectId he holds. )
Then check the count of dictionary. If it is zero you can make sure that your downloads are completed. So you can call your viewcontroller.
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.
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.