Question

I have very simple method that is being called by performSelector:withObject:afterDelay: however no matter what value I assign to afterDelay, the method is always fired after a 10 second delay. The method calls a URLRequest that when complete, invokes another request (not sure this has implications or not).

I have:

-(void)connectionDidFinishLoading:(NSURLConnection*)connection {
    [self performSelector:@selector(poll) withObject:nil afterDelay: 1];
}
.....
-(void)poll
{
    NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
    ....
    NSURLConnection *connection = [[[NSURLConnection alloc] initWithRequest:request delegate:self] autorelease];
    .....
}

No matter what value I assign to afterDelay, the method is always invoked after 10 seconds. Any ideas as to what might cause this?

Answer 1

Is your NSURLConnectionDelegate getting messages on a thread different from the main thread? If so then post your message to the mainThread instead:

NSLog(@"WILL SEND wait1sec");
[self performSelectorOnMainThread:@selector(wait1sec) withObject:nil waitUntilDone:NO];

then

- (void)wait1sec
{
    NSLog(@"GOT wait1sec");
    [self performSelector:@selector(poll) withObject:nil afterDelay: 1];
}
- (void)poll
{
    NSLog(@"GOT poll()");
    ...

PS: you can do this more easily with dispatch_after() but you didn’t mention blocks so didn’t go there.

PS: try adding this to all your delegate messages:

-(void....
{
    assert([NSThread isMainThread]);
    ...

If that does not crash your app, then something is blocking our main runLoop – the one on your main thread – so you are probably waiting on something somewhere. In this case your UI would be totally unresponsive.