How to run NSTimer until flag variable ON in Cocoa - objective-c

Question

I have a problem: I want to NSTimer waiting until FLAG variable is YES, if FLAG = YES, myTimer is stop. How can i do that? I tried below code:
NSTimer *myTimer;
int delay = 6.0;
scanTimer= [NSTimer scheduledTimerWithTimeInterval:6.0 target:self selector:#selector(anotherfunc) userInfo:nil repeats:YES];
myTimer= [NSTimer timerWithTimeInterval: delay
target:self
selector: #selector(resetAll:) userInfo:nil
repeats:NO];
[[NSRunLoop currentRunLoop] addTimer:myTimer forMode:NSModalPanelRunLoopMode];
[[NSApplication sharedApplication] runModalForWindow: scanningPanel];
This is resetAll () function :
-(void) resetAll: (NSTimer *) theTimer
{
if(FLAG)
{
NSLog(#"killWindow");
[[NSApplication sharedApplication] abortModal];
[scanningPanel orderOut: nil];
FLAG = NO;
}
else
{
delay +=6.0;
myTimer= [NSTimer timerWithTimeInterval: delay
target:self
selector: #selector(resetAll:) userInfo:nil
repeats:NO];
[[NSRunLoop currentRunLoop] addTimer:myTimer forMode:NSModalPanelRunLoopMode];
[[NSApplication sharedApplication] runModalForWindow: scanningPanel];
}
}
I used 2 NSTimer, but only myTimer run, scanTimer not run. Please give me any suggestions. Thanks in advance

Answer 1

Why not use Key Value Observing for the FLAG change? Add the flag variable as a property of the class you're working in:
#property(nonatomic, assign) BOOL flag;
To avoid repetition place in your .m:
#define kFooFlagKey #"flag"
Override -setFlag: so it is KVO compliant:
-(void)setFlag:(BOOL)flag
{
if (_flag == flag) {
return;
}
[self willChangeValueForKey:kFooFlagKey];
_flag = flag;
[self didChangeValueForKey:kFooFlagKey];
}
In the class' initializer add self as the observer for the keypath you'd like to monitor. In this case it will be for the property "flag".
[self addObserver:self
forKeyPath:kFooFlagKey
options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld
context:NULL];
Don't forget to remove the observer in the class' -dealloc:
[self removeObserver:self forKeyPath:kFooFlagKey];
Create the timer to fire repeatedly (firingCallBack is a method called with each fire):
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.0f
target:self
selector:#selector(firingCallBack)
userInfo:nil
repeats:YES];
Implement KVO observing method:
-(void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
if ([keyPath isEqualToString:kFooFlagKey]) {
if (self.flag) {
[self performSelector:#selector(resetAll) withObject:nil afterDelay:0.0f];
}
}
}
Implement -resetAll however you'd like. It will be called when you are setting the flag variable via the accessor AND the flag is set to YES

Answer 2

Try like this:-
NSTimer *myTimer;
int delay = 6.0;
scanTimer= [NSTimer scheduledTimerWithTimeInterval:6.0 target:self selector:#selector(anotherfunc) userInfo:nil repeats:YES];
myTimer= [NSTimer scheduledTimerWithTimeInterval: delay
target:self
selector: #selector(resetAll:) userInfo:nil
repeats:NO];
[NSApp beginSheet:scanningPanel modalForWindow:[self window]
modalDelegate:self
didEndSelector:nil
contextInfo:self];
- (void)resetAll:(NSTimer *)theTimer
{
if (flag== YES)
{
[NSApp endSheet:scanningPanel];
[scanningPanel orderOut:self];
flag=NO;
}
else
{
delay +=6.0;
myTimer= [NSTimer scheduledTimerWithTimeInterval: delay
target:self
selector: #selector(resetAll:) userInfo:nil
repeats:NO];
[NSApp beginSheet:scanningPanel modalForWindow:[self window]
modalDelegate:self
didEndSelector:nil
contextInfo:self];
}
}

Answer 3

You just start the timer (already scheduled) and make it repeat at a relatively high frequency and stop it when the condition is met. One timer can act as two, like this:
- (void)startTimers {
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:#selector(timerFired:) userInfo:nil repeats:YES];
}
- (void)timerFired:(NSTimer *)timer {
if (self.stopTimerA && self.stopTimerB) {
[timer invalidate];
} else {
if (!self.stopTimerA)
[self timerAFired];
if (!self.stopTimerB)
[self timerBFired];
}
}
- (void)timerAFired {
// this can be coded like it has it's own timer
// we didn't pass the timer, so we can't invalidate it
// to stop...
self.stopTimerA = YES;
}
- (void)timerBFired {
// same idea here
}