Question

i don’t want to write a code like “myview.timer invalidate” before [myview release].
but if the timer is working, i can’t release myview, because timer retain myview.
how can i do?

i want to make the class”myview” simple, just call [myview init] and [myview release]

myview.h

@interface MyView : UIView {
    NSString *str;
    NSTimer *timer;
}
@property(nonatomic, retain) NSString *str;
@property(nonatomic, assign) NSTimer *timer;
- (void)start;
- (void)doAction;
@end

myview.m

@implementation MyView
@synthesize str, timer;
- (id)initWithFrame:(CGRect)frame {

    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code.
        NSString *_str = [[NSString alloc] initWithFormat:@"Timer is Running!!! Not Release"];
        self.str = _str;
        [_str release];
    }
    return self;
}

- (void)start {
    NSTimer *_timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(doAction) userInfo:nil repeats:YES];
    self.timer = _timer;
}

- (void)doAction {
    NSLog(@"%@",self.str);
}


- (void)dealloc {
    [str release];
    [timer invalidate];
    timer = nil;
    [super dealloc];
}

contrllor.m

- (void)viewDidLoad {
    MyView *my_view = [[MyView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
    self.myView = my_view;
    [my_view release];

    [myView start];
    [self.view addSubview:myView];

    [super viewDidLoad];
}

- (IBAction)releaseMyView {
    [myView removeFromSuperview];
    [myView release];
}

Answer 1

Repetitive timer retains its target. So if you use repetitive timer then you must invalidate it, and the place to invalidate must not be dealloc. dealloc won’t be called unless you invalidate the timer. That’s the way NSTimer is designed. As you have a start method, you can write a stop method which will invalidate the timer, if you are looking for more readable code. The logic is simple: you need to stop if you have started.

Another option is instead of self you can use a different object as the target of the timer. Then you can invalidate the timer in dealloc. But probably this is not worth the effort.