Array nil (even when addObject:) [duplicate] - iphone

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Closed 11 years ago.
Possible Duplicate:
addObject: to array not working (array still nil)
EVERYTHING UPDATED
This app is a table view with a tab bar controller. I am logging the count of the array: arrayOfFavourites and even though i add an object is continues to have a nil value, my relating code, all objects shown are allocated and initialized in the code (previous or present) some are instances and some are properties:
ListViewController.m:
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"TOUCHED CELL!");
// Push the web view controller onto the navigation stack - this implicitly
// creates the web view controller's view the first time through
[[self navigationController] pushViewController:webViewController animated:YES];
// Grab the selected item
entry = [[channel items] objectAtIndex:[indexPath row]];
if (!entry) {
NSLog(#"!entry");
}
// Construct a URL with the link string of the item
NSURL *url = [NSURL URLWithString:[entry link]];
// Construct a request object with that URL
NSURLRequest *req = [NSURLRequest requestWithURL:url];
// Load the request into the web view
[[webViewController webView] loadRequest:req];
// Take the cell we pressed
// IMPORTANT PART
CELL = [tableView cellForRowAtIndexPath:indexPath];
[webViewController setItem:entry];
webViewController = nil;
webViewController = [[WebViewController alloc] init];
[entry release];
}
WebViewController.m:
You shake to favorite a cell
-(void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
cellToPassOn = nil;
NSLog(#"Favouriting"); // YES I KNOW SPELLING
// This is pretty simple, what we do is we take the cell we touched and take its title and link
// then put it inside an array in the Favourites class
Favourites *fav = [[Favourites alloc] init];
ListViewController *list = [[ListViewController alloc] init];
[self setCellToPassOn: [list CELL]];
if (!item) {
NSLog(#"NILLED ITEM");
}
[[fav arrayOfFavourites] addObject:[item autorelease]];
[fav setCell: cellToPassOn];
}
Favourites.m:
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"ROWS NO.");
NSLog(#"%i", [arrayOfFavourites count]);
return [arrayOfFavourites count];
}
Favourites:
A CLASS, ON TAB BAR CONTROLLER
WEBVIEWCONROLLER:
CONTROLLER FOR DIFFERENT WEB VIEWS
LISTVIEWCONTROLLER:
DATA PROVIDER
Actually what happens is when i shake i reload the table view data and i add an object to an array (array of favorites) the count is one.... GOOD! But then when i shake again (in a different article, my app has different webViews when i press different cells.) It is still 1... weird.... if i go to favorites class that array remains one.. ok... so as you can see i am returning the arrayOfFavourites count to numberOfRowsInSection (which is 1) but no cells appear and the cellForRowAtIndexPath is never called (using an NSLOG) why is this happening I AM VERY ANNOYED!

Answer 1

In your Favourites.m numberOfRowsInSection function, looks like you should do this:
if(arrayOfFavourites == NULL)
{
arrayOfFavourites = [[NSMutableArray alloc] init];
}
Because you're reinitializing (and likely leaking) in every single call to numberOfRowsInSection (which gets called each time the table needs to know how many rows it must display -- i.e. very often).

Answer 2

You create and destroy a new Favourites object every time you go through -motionBegan:withEvent:, and you create a new array every time you go through -tableView:numberOfRowsInSection:. If you want data to persist beyond those events, you need to keep the objects around.

Answer 3

Let review this part of your code :
-(void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event {
cellToPassOn = nil;
NSLog(#"Favouriting"); // YES I KNOW SPELLING
// This is pretty simple, what we do is we take the cell we touched and take its title and link
// then put it inside an array in the Favourites class
// HERE you are creating a NEW fav
Favourites *fav = [[Favourites alloc] init];
// HERE you are creating a NEW list
ListViewController *list = [[ListViewController alloc] init];
// SO HERE what is "CELL" doing, returning some constant or static object?
[self setCellToPassOn: [list CELL]];
// HERE what is item and where does it come from
if (!item) {
NSLog(#"NILLED ITEM");
}
// Here you take an array of an object you just created and autoreleasing the item
// this is not the regular way to handle memory management in Cocoa,
// depending on what you are doing to item else where you could get item == deallocated pretty soon
[[fav arrayOfFavourites] addObject:[item autorelease]];
[fav setCell: cellToPassOn];
HERE you are releasing fav
[fav release];
HERE fav don't exist anymore as well as the array to which you've added something to it.
[list release];
item = nil;
}
Unless I'm reading your code incorrectly I have the feeling that you are trying to have some persistence with "volatile" object.
You need to make a #property for those object to survive longer that one method call.
Every time you create a new object it's new and have no knowledge of the precedent one.
And if we look at this code :
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// HERE everytime the tableview is asking for the numberOfRowsInSection, you create a new array
// And that new empty array is replacing your old one.
// That is your "weird" thing, it's doing what you are asking it to do, set it back to a new empty array.
arrayOfFavourites = [[NSMutableArray alloc] init];
NSLog(#"ROWS NO.");
NSLog(#"%i", [arrayOfFavourites count]);
return [arrayOfFavourites count];
}