[Cocoa] Placing an NSTimer in a separate thread
- by ndg
I'm trying to setup an NSTimer in a separate thread so that it continues to fire when users interact with the UI of my application. This seems to work, but Leaks reports a number of issues - and I believe I've narrowed it down to my timer code.
Currently what's happening is that updateTimer tries to access an NSArrayController (timersController) which is bound to an NSTableView in my applications interface. From there, I grab the first selected row and alter its timeSpent column.
From reading around, I believe what I should be trying to do is execute the updateTimer function on the main thread, rather than in my timers secondary thread.
I'm posting here in the hopes that someone with more experience can tell me if that's the only thing I'm doing wrong. Having read Apple's documentation on Threading, I've found it an overwhelmingly large subject area.
NSThread *timerThread = [[[NSThread alloc] initWithTarget:self selector:@selector(startTimerThread) object:nil] autorelease];
[timerThread start];
-(void)startTimerThread
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
activeTimer = [[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateTimer:) userInfo:nil repeats:YES] retain];
[runLoop run];
[pool release];
}
-(void)updateTimer:(NSTimer *)timer
{
NSArray *selectedTimers = [timersController selectedObjects];
id selectedTimer = [selectedTimers objectAtIndex:0];
NSNumber *currentTimeSpent = [selectedTimer timeSpent];
[selectedTimer setValue:[NSNumber numberWithInt:[currentTimeSpent intValue]+1] forKey:@"timeSpent"];
}
-(void)stopTimer
{
[activeTimer invalidate];
[activeTimer release];
}
