iPhone dev, NSDictionary how to retain full Dict? - iphone

Question

I have a problem with retaining data in a nested NSDictionary. Or is it something with NSMutableDictionary that will make this work? Take a look, I will try to explain as good as possible.
My .h file looks like:
#interface MyViewController : UIViewController
<UITableViewDataSource, UITableViewDelegate>
{
NSDictionary *fullData;
IBOutlet UITableView *tableView;
}
#property (nonatomic, retain) NSDictionary *fullData;
#property (nonatomic, retain) UITableView *tableView;
#end
I set up my inits in viewDidLoad
- (void)viewDidLoad {
...
fullData = [NSDictionary dictionaryWithContentsOfURL:url];
[fullData retain];
[super viewDidLoad];
}
And this works fine when I try to insert it into UITableViewCells and whatever I need to do, even if I do an NSLog that prints fullData here, all of the data will be displayed.
like so:
2010-11-24 14:49:53.334 MyApp[25543:40b] {
items = (
{
id = 5;
localId = 1;
name = "A name1";
},
{
id = 8;
localId = 3;
name = "A name2";
},
{
id = 9;
localId = 4;
name = "A name3";
},
{
id = 10;
localId = 5;
name = "A name4";
},
{
id = 11;
localId = 6;
name = "A name5";
}
);
results = 5;
}
Although this works perfectly I want to keep the fullData in my other events, for example didSelectRowAtIndexPath. First of all, I have to retain the , and also if I do, only the first level data will be retained. the dict items will just point to some memory which doesn't exist.
So I try:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Data: %#", fullData);
}
And this sometimes returns this:
2010-11-24 14:44:28.288 MyApp[25493:40b] Data: {
items = (
"<_NSIndexPathUniqueTreeNode: 0x9d2a820>",
"<CALayer: 0x9d27980>",
"<CALayer: 0x9d2bc30>",
"<CALayer: 0x9d29830>",
"<CALayer: 0x9d299e0>"
);
results = 5;
}
It seems like some values are retained, however the data inside items are not possible to access. Is it better for me to store the data to a local file and then access it again at this point, or should be it possible to retain the full dictionary?
I tried adding [[fullData objectForKey:#"items"] retain];
I am pretty new to this, so I need help to make my code follow best practices as well. I have tried many solutions and watched several movies from apple and other places too. I just can't solve it. It might be simple but I dont know where to look.
Thank you.
I am sorry, I did solve the issue myself
I didn't include this function:
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Retain count: %i", [fullData retainCount]);
UITableViewCell *cell =
[tableView dequeueReusableCellWithIdentifier:#"cell"];
// create a cell
if( cell == nil )
{
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"cell"];
}
// fill it with content
NSArray *current = [[fullData objectForKey:#"items"] objectAtIndex:indexPath.row];
NSString *rowLabel = [NSString stringWithFormat:#"%#, %#",[current valueForKey:#"localId"], [current valueForKey:#"name"]];
cell.textLabel.text = rowLabel;
[current release];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
// return it
return cell;
}
And the issue is that I release the current variable each row in the table. This should be a result of that the instance in the variable current is not a copy, instead it is the real reference.
Thanks anyways.

Answer 1

fullData = [NSDictionary dictionaryWithContentsOfURL:url];
is auto-released. you shouldn't retain it. Use this:
self.fullData = [[NSDictionary alloc] initWithContentsOfURL:url];
And I don't think you need to retain it for your purposes now. Only if you need to access it after MyViewController is released.
Are you releasing the UITableView? It may go through and release it's cells which are in your NSDictionary. W/o more code, I can't tell.

Answer 2

You'll need to post some more code in order to track down the solution. The NSDictionary retains its contents, so unless you are over-releasing the objects somewhere else, retaining the NSDictionary will be sufficient.

Answer 3

I am sorry, I did solve the issue myself
I didn't include this function:
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Retain count: %i", [fullData retainCount]);
UITableViewCell *cell =
[tableView dequeueReusableCellWithIdentifier:#"cell"];
// create a cell
if( cell == nil )
{
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"cell"];
}
// fill it with content
NSArray *current = [[fullData objectForKey:#"items"] objectAtIndex:indexPath.row];
NSString *rowLabel = [NSString stringWithFormat:#"%#, %#",[current valueForKey:#"localId"], [current valueForKey:#"name"]];
cell.textLabel.text = rowLabel;
[current release];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
// return it
return cell;
}
And the issue is that I release the current variable each row in the table. This should be a result of that the instance in the variable current is not a copy, instead it is the real reference.
Thanks anyways.