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Use of NSTimer

bleasdellbleasdell Posts: 17Registered Users
in iPhone SDK Development
I have a situation (perhaps unique) that is causing me grief and I am hoping that someone can help me to get this straightened out.

Let me just jump right in with the code:

-(void)loadView {
	[self StartFadeItems];
}

-(void)StartFadeItems {
	timerFade = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(FadeItems) userInfo:nil repeats:NO];
}

-(void)ResetFadeItems {
	[UIView beginAnimations:nil context:NULL];
	[UIView setAnimationDuration:1];
	[infoButton setAlpha:dimmerAlpha];
	[mySwitch setAlpha:dimmerAlpha];
	[myLabel setAlpha:dimmerAlpha];
	[UIView commitAnimations];
	[self StartFadeItems];
}

-(void)FadeItems {
	[UIView beginAnimations:nil context:NULL];
	[UIView setAnimationDuration:1];
	[infoButton setAlpha:0];
	[mySwitch setAlpha:0];
	[myLabel setAlpha:0];
	[UIView commitAnimations];
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
	[self ResetFadeItems];
}


So the jist is that when the user touches the screen these three items will fade in, and after 5 seconds, the items will fade out. The problem is that I want the behavior to be such that the timer is invalidated if the user touches the screen more than once in the 5 second period and have the timer reset. In other words:

0:00 - app launched
0:05 - items fade out
0:10 - user touches screen, items fade in
0:15 - items fade out
0:20 - user touches screen, items fade in
0:22 - user touches screen again, items remain visible
0:27 - items fade out

I have tried putting in a [timerFade invalidate]; in the ResetFadeItems method, but that causes a "BAD_EXC_EXCEPTION" exception. I have tried wrapping the invalidate message inside an "if (timerFade != nil) {" statement, but still get the same exception. I have also done a "timerFade = nil;" after the invalidate, to no avail.

Thanks in advance for your help.
Post edited by bleasdell on
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Replies

  • detzdetz Posts: 394Registered Users
    How about just resetting the timer when there is a click...

    			 [fadeTimer setFireDate:[NSDate dateWithTimeIntervalSinceNow:5]];
    Super Pig

    iO
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  • bleasdellbleasdell Posts: 17Registered Users
    First, thanks for the quick reply.

    Second, I am having trouble fitting what you suggested into my code. I am sort of new to this so please bear with me. I can use setFireDate but I still have to init the timer object so that it knows what selector to trigger, correct? If I do that I get a crash when I call setFireDate. Here is the code:


    -(void)loadView {
    	[self StartFadeItems];
    }

    -(void)StartFadeItems {
    	if ([timerFade isValid]){
    		[timerFade setFireDate:[NSDate dateWithTimeIntervalSinceNow:5]];
    	}else{
    		[timerFade release];
    		timerFade = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(FadeItems) userInfo:nil repeats:NO];
    	}
    }

    -(void)ResetFadeItems {
    	[UIView beginAnimations:nil context:NULL];
    	[UIView setAnimationDuration:1];
    	[infoButton setAlpha:dimmerAlpha];
    	[mySwitch setAlpha:dimmerAlpha];
    	[myLabel setAlpha:dimmerAlpha];
    	[UIView commitAnimations];
    	[timerFade setFireDate:[NSDate dateWithTimeIntervalSinceNow:5]];
    	[self StartFadeItems];
    }

    -(void)FadeItems {
    	[UIView beginAnimations:nil context:NULL];
    	[UIView setAnimationDuration:1];
    	[mySwitch setAlpha:0];
    	[infoButton setAlpha:0];
    	[myLabel setAlpha:0];
    	[UIView commitAnimations];
    }

    -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    	[self ResetFadeItems];
    }


    What am I missing? I am guessing it is something simple, so be gentle.
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  • detzdetz Posts: 394Registered Users
    Change StartFadeItems to

    if (timerFade){
    		[timerFade setFireDate:[NSDate dateWithTimeIntervalSinceNow:5]];
    	}else{
    		timerFade = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(FadeItems) userInfo:nil repeats:NO];
    	}



    In the function FadeItems ad

    timerFade = nil;
    [timerFade invalidate];
    [timerFade release];



    If you get crashes add some break points and step through your program to find the line that is crashing.
    Super Pig

    iO
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  • bleasdellbleasdell Posts: 17Registered Users
    detz,

    Thank you VERY much for your help. The code you offered wasn't 100% perfect, but it led me to the solution. Here is the solution as I found it:


    -(void)loadView {
    	[self StartFadeItems];
    }

    -(void)StartFadeItems {
    	timerFade = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(FadeItems) userInfo:nil repeats:NO];
    }

    -(void)ResetFadeItems {
    	[UIView beginAnimations:nil context:NULL];
    	[UIView setAnimationDuration:1];
    	[infoButton setAlpha:dimmerAlpha];
    	[mySwitch setAlpha:dimmerAlpha];
    	[myLabel setAlpha:dimmerAlpha];
    	[UIView commitAnimations];
    	if ([timerFade isValid]) {
            [timerFade setFireDate:[NSDate dateWithTimeIntervalSinceNow:5]];
        }else{
    		[self StartFadeItems];
    	}
    }

    -(void)FadeItems {
    	[UIView beginAnimations:nil context:NULL];
    	[UIView setAnimationDuration:1];
    	[mySwitch setAlpha:0];
    	[infoButton setAlpha:0];
    	[myLabel setAlpha:0];
    	[UIView commitAnimations];
    		timerFade = nil;
    		[timerFade invalidate];
    		[timerFade release]; 
    }

    -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    	[self ResetFadeItems];
    }


    Again, thank you very, very much for helping me out.
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