I would like to perform a selector on the main thread from another thread, but the selector has multiple arguments, similar to this: -(void) doSomethingWith:(int) a b:(float)b c:(float)c d:(float)...

i am doing function call with scheduledTimerWithTimeInterval. i am just checking that xml parsing is completed or not for particular web services and invalidating timer in didEndElement method afte...

How can I run an arbitrary selector on an object, the return of which is a double? For example, I have obj A, which has method -(double)blah; How can I do double res = [obj performSelector:@select...

In my iPhone app I got several places where I can do a [object performSelector: withObject: afterDelay:] call. All lead to the same method. Now, in that method I want to execute some code only o...

I'm writing a client-server app to iPhone. And I have a question about threading. When I access my online database from the device, I need to do this on a separate thread to not freeze the UI/main ...

Grand Central Dispatch is great and reduces the amount of code but why I cannot run something on a background thread? I have made a sample application to show what I mean (none of the commented wor...