Question

I am using

[self performSelector:@selector(someMethod) withObject:nil afterDelay:1];

to call a method again and again after a time delay. It’s Working fine but my problem is, even though I navigate to next class, perform selector is running background in the previous class.

So I try to cancel it by using the following

[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(someMethod) object:nil]; 

but it’s not working. I did this in viewDidDisappear. Can anyone tell me how to cancel perform selector?

Here is my code

-(void)textCalling
{


    NSString *str2=@"Something";
    UILabel *lbl =(UILabel*)[arrObj objectAtIndex:count2];
    [lbl setAlpha:0];
    lbl.numberOfLines=0;
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
    lbl.text=str2;
    [UIView setAnimationDuration:0.0];
    [lbl setAlpha:0];
    [UIView commitAnimations];

}
-(void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context
{

    UILabel *lbl =(UILabel*)[arrObj objectAtIndex:count2];
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:2.0];
    [lbl setAlpha:1];
    [UIView commitAnimations];
    count2++;
    if (count2<[arrCourse count]) {
        [self performSelector:@selector(textCalling) withObject:nil afterDelay:1];
    }else{
        count2=0;

        [self performSelector:@selector(imageCallingCourse) withObject:nil afterDelay:1];
    }
}
-(void)imageCallingCourse
{

    imgViewObj.image=[UIImage imageNamed:@"Objective.png"];
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(animationDidStopImageCourse:finished:context:)];
    [UIView setAnimationDuration:0.0];
    [imgViewObj setAlpha:0];
    [UIView commitAnimations];
}

-(void)animationDidStopImageCourse:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context
{
    NSLog(@"animationDidStopImage1");
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:2.0];
    [imgViewObj setAlpha:1];
    [UIView commitAnimations];


}

Answer 1

In .h,

BOOL checkMethodCall;

In .m viewWillAppear,

checkMethodCall = NO;

In viewWillDisappear,

checkMethodCall = YES;

then,

-(void)textCalling
{
  if(checkMethodCall)
  {
    return;
  }
  // Your code
}

so after changing the view the code after return in method wiil not excecute..