Question

.h:

#import <UIKit/UIKit.h>
#import "Todo.h"
@interface TodoCostApplyViewController : UIViewController

{
    NSThread* headViewThread;
    NSThread* tableViewThread;
}
@property (nonatomic, retain) NSThread* headViewThread;
@property (nonatomic, retain) NSThread* tableViewThread;
@end

.m:

@interface TodoCostApplyViewController ()
@end
- (void)viewDidLoad
{
    [super viewDidLoad];
    headViewThread = [[NSThread alloc] initWithTarget:self
                                             selector:@selector(drawHeadView)
                                               object:nil];
    [headViewThread start];
    tableViewThread = [[NSThread alloc] initWithTarget:self
                                         selector:@selector(drawTableView)
                                           object:nil];
    [tableViewThread start];   
}

- (void)dealloc
{
    [tableViewThread release];
    [headViewThread release];
}

Is there a leak of memory about tableViewThread and headViewThread ?
And if there is a leak, what should I do with this problem?
Thank you in advance!

Answer 1

Yes, there is a potential leak. viewDidLoad can potentially be called multiple times, in which case you would see memory leaks. Everything you retain in viewDidLoad should be released (and set to nil) at the latest in viewDidUnload (and also in dealloc).

Had you used the synthesized setters in viewDidLoad (as you should almost always do), the problem would be mitigated because every time viewDidLoad was executed, the old thread objects would get released when you assigned the new ones.