Re: When to 'release' in Cocoa management?
Re: When to 'release' in Cocoa management?
- Subject: Re: When to 'release' in Cocoa management?
- From: DairyKnight <email@hidden>
- Date: Fri, 21 Aug 2009 17:08:58 +0800
One more thing, it has nothing to do with the DateFormatter. So somehow
UIDatePicker released its date somewhereoutside of my code... I guess it has
something to do with autoreleasepool.
On Fri, Aug 21, 2009 at 5:07 PM, DairyKnight <email@hidden> wrote:
>
> OK. Here's the code of my UIViewController:
>
> - (void)viewDidLoad {
>
> [super viewDidLoad];
>
> okButton = [[UIBarButtonItem alloc] initWithTitle:@"OK" style:
> UIBarButtonItemStyleBordered target:self action:@selector(okAction:)];
>
> self.navigationItem.rightBarButtonItem = okButton;
>
> [okButton release];
>
> [self.view setBackgroundColor:[UIColor blackColor]];
>
> NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
>
> [dateFormatter setDateFormat:@"H : m"];
>
> NSDate *date = [dateFormatter dateFromString:@"0 : 0"];
>
> [picker setDate:date];
>
> [dateFormatter release];
>
> }
>
> and if you click on the button, in
> -(void) okAction:(id) sender
>
> {
> }
> the Reference count of 'date' is somehow mystically decreased by 1. There's
> no other code in the message
> loop, and what I did was directly press the button on the View.
>
>
>
> On Fri, Aug 21, 2009 at 3:38 PM, Graham Cox <email@hidden>wrote:
>
>>
>> On 21/08/2009, at 5:32 PM, DairyKnight wrote:
>>
>> NSDate *date = [[NSDate alloc] init];
>>> [picker setDate:date];
>>> [date release]; // Opps! immediate release of 'date' causes program
>>> crash.
>>>
>>>
>>> So is there a rule of thumb, like when should we release immediately
>>> after
>>> passing the object to some Cocoa API calls?
>>>
>>
>>
>> This should work OK, so if it's crashing, you have a bug elsewhere.
>>
>> Once you are no longer interested in an object, you are free to release
>> it. Another object that needs to keep it will retain it.
>>
>> --Graham
>>
>>
>>
>
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