Handling a button action while a timer loop is running

[That Don Guy]

I have an app that checks integers one at a time until it finds one that meets a particular conditions. Since this check may take quite a bit of time, I want to be able to interrupt it with a UIButton. The method I am currently using is to create a non-repeating NSTimer with an interval of 0.001 seconds that calls an action that checks the next 100 integers, then, if none of them met the conditions, create a new NSTimer identical to the previous one and add it to currentRunLoop.
There is also a boolean variable runProcess, initially set to YES, and a UIButton labelled "Stop" that sets it to NO. In the method called when the timer is fired, if runProcess = NO, the new timer is not created. (Using an NSTimer allows for the button click to be detected in the middle of the processing.)

The NSTimer is not repeating as the processing within the called method takes longer than 1 millisecond, and I do not want messages from the timer to "stack up" so they would continue to be handled even after the processing is done and the timer no longer needs to be fired.

Is this the best way to do something like this? Would having a repeating timer (and then check to see if runProcess = YES before doing any of the processing) be better? Is using a short-period NSTimer even the way to go about this?

-- Don

[Ice_2k]

I would create a background thread to handle the processing instead of this timer algorithm. The stopping method can be the same as the one you're using right now (the background thread would process 100 units, then check its runProcess flag and decide if to quit or carry on).

[That Don Guy]

Thanks for the tip; that works - and I was surprised that it works the way I wanted it to work without having to do anything with Run Loops. (I think the only real hoop I had to jump through was having to call performSelectorOnMainThread to get a string to display from the background thread to the main thread.

-- Don