CODEWITHSUNDEEP
objective-c
S.J. Lim
S.J. Lim

Reputation: 3165

Why this code be terminated?

I has written following code and then run. In after, When I touch uibutton, this app is terminated.

I want to know why terminated.

I doubt if autorelease?

Are there anyone who can explicitly explain

why myClass instance is released and

where myClass is released and

the way that myClass can use autorelease? 

    @interface MyClass : NSObject
    - (void)testMethod;
    @end

    @implementation MyClass{
        NSMutableArray *array;
    }

    - (id)init{
        if ((self = [super init])) {
            array = [[NSMutableArray alloc] initWithCapacity:0];
        }
        return self;
    }

    - (void)dealloc {
        [array release];
        [super dealloc];
    }

    - (void)testMethod {
        NSLog(@"after init : %@", array);
    }

    @end

    @implementation ViewController {
        MyClass *myClass;
    }

    - (void)viewDidLoad
    {
        [super viewDidLoad];
        // Do any additional setup after loading the view, typically from a nib.

        myClass = [[[MyClass alloc] init] autorelease];  <== cause of ternimate?

        UIButton *aButton=[UIButton buttonWithType:UIButtonTypeRoundedRect];
        [aButton addTarget:self action:@selector(testArray:) forControlEvents:UIControlEventTouchUpInside];
        aButton.frame=CGRectMake(110.0f, 129.0f, 100.0f, 57.0f);
        [aButton setTitle:@"title" forState:UIControlStateNormal & UIControlStateHighlighted & UIControlStateSelected];
        [self.view addSubview:aButton];

    }

    - (void)testArray:(id)sender {
        [myClass testMethod];
    }
@end

Upvotes: 0

Views: 74

Answers (3)

Jesse Black
Jesse Black

Reputation: 7976

It is the autorelease that is causing an issue.

You should make myClass a property.

@implementation ViewController {

    }
    @property (nonatomic, retain) MyClass *myClass;

    @synthesize myClass
    -(void)dealloc
    {
      [myClass release];
      [super dealloc];
    }
    - (void)viewDidLoad
    {
        [super viewDidLoad];
        // Do any additional setup after loading the view, typically from a nib.

        self.myClass = [[[MyClass alloc] init] autorelease];

        UIButton *aButton=[UIButton buttonWithType:UIButtonTypeRoundedRect];
        [aButton addTarget:self action:@selector(testArray:) forControlEvents:UIControlEventTouchUpInside];
        aButton.frame=CGRectMake(110.0f, 129.0f, 100.0f, 57.0f);
        [aButton setTitle:@"title" forState:UIControlStateNormal & UIControlStateHighlighted & UIControlStateSelected];
        [self.view addSubview:aButton];

    }

    - (void)testArray:(id)sender {
        [myClass testMethod];
    }

Upvotes: 0

user529758
user529758

Reputation:

Seems that due to

myClass = [[[MyClass alloc] init] autorelease];

the instance of MyClass is already deallocated when you touch the button. Don't be lazy - autorelease is not an ultimate 'solve my memory management problem and make me not have to think' solution - here you need to use just

myClass = [[MyClass alloc] init];

then release it manually when needed - probably in your ViewController class' -dealloc method.

Upvotes: 0

mipadi
mipadi

Reputation: 410662

myClass = [[[MyClass alloc] init] autorelease];

Probably because you're autoreleasing myClass. It's an instance variable, so it should be retained (and then released in the class's dealloc method).

Upvotes: 1

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