CODEWITHSUNDEEP
iphonecocoa-touchdebuggingmemory-leaksmemory-management
Marcal
Marcal

Reputation: 1371

Potential Memory leak, and I don't know why

I have the following code which adds a label into a footer of a UITableView, so that I can format the text (white, etc.)

It works ok, but it gives me a leak warning for the "headerLabel" when analyzing it on the line with the "return"

        // create the parent view that will hold header Label
UIView* customView = [[UIView alloc] initWithFrame:CGRectMake(0.0, 15.0, 300.0, 44.0)];

    // create the button object
UILabel * headerLabel = [[UILabel alloc] initWithFrame:CGRectZero];
headerLabel.backgroundColor = [UIColor clearColor];
headerLabel.opaque = NO;
headerLabel.textColor = [UIColor whiteColor];
headerLabel.highlightedTextColor = [UIColor whiteColor];
headerLabel.font = [UIFont systemFontOfSize:14];
headerLabel.textAlignment=UITextAlignmentCenter;
headerLabel.frame = CGRectMake(10.0, 0.0, 300.0, 75.0);
headerLabel.numberOfLines=4;

if (section==0) {

    headerLabel.text = @"If turned off, the last used settings will be used on the next session\n\n"; // i.e. array element

}


[customView addSubview:headerLabel];

    //[headerLabel release];

return customView;
    // [customView release];

I've tried to put the release here and there, but it's always the same.

I'd appreciate some feedback from you guys.

Upvotes: 0

Views: 353

Answers (4)

Dan
Dan

Reputation: 17445

autorelease your customView and make sure you are releasing headerLabel after you add it as a subview. Anytime you call alloc/init you are taking ownership, you need to make sure you release those objects. Since you are returning customView from this method it makes sense to defer your release of that object (using autorelease) so it can be used by the calling object. 

// create the parent view that will hold header Label
UIView* customView = [[[UIView alloc] 
                          initWithFrame:CGRectMake(0.0, 15.0, 300.0, 44.0)] 
                          autorelease];

// create the button object
UILabel * headerLabel = [[UILabel alloc] initWithFrame:CGRectZero];
headerLabel.backgroundColor = [UIColor clearColor];
headerLabel.opaque = NO;
headerLabel.textColor = [UIColor whiteColor];
headerLabel.highlightedTextColor = [UIColor whiteColor];
headerLabel.font = [UIFont systemFontOfSize:14];
headerLabel.textAlignment=UITextAlignmentCenter;
headerLabel.frame = CGRectMake(10.0, 0.0, 300.0, 75.0);
headerLabel.numberOfLines=4;

if (section==0) {
    headerLabel.text = @"If turned off, the last used settings will be used on the next session\n\n"; // i.e. array element
}

[customView addSubview:headerLabel];

[headerLabel release];

return customView;

Upvotes: 1

Ole Begemann
Ole Begemann

Reputation: 135588

  1. You have to release headerLabel before exiting the method:

    [headerView release];

  2. You probably should autorelease customView unless your method name includes the words new, alloc or copy (in that case, the caller would have to release the returned view):

    return [customView autorelease];

Upvotes: 1

vikingosegundo
vikingosegundo

Reputation: 52237

try 

[headerLabel release];
return [customView autorelease];

Upvotes: 1

stevex
stevex

Reputation: 5827

Based on the code sample you've got here, the first release would be correct. (Releasing after the return statement wouldn't make sense). You took ownership of the object when you created it, and you need to release it.

You can use Instruments to track where object is being retained and released; you can see a history of the leaky object to see exactly what's going on. That would be your best bet here.   Launch your app with the Leaks instrument, and when you find the leaking object, click the arrow to the right of the address. This will show you the object's history - every retain and release.

Upvotes: 0

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