Question

I have been trying to add a button after a parser ( on a seperate thread ) is complete. I understand you cannot interact with UI elements on any thread other than the main thread.

I do not want to use a timer, or a while statement… so my question is

Once the parser is done what do you suggest I do to add the button to the view? I do not want it added before because the user will get to a blank table. I also do not want to reload the table when done because the presents other problems for me.

the performSelector on main thread does not seem to work for me either.. ? Im kind of lost here…

Any suggestions?

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Here is where I kick off to another thread to start parser (In AppDelegate)

// begin background downloads
[NSThread detachNewThreadSelector:@selector(parseNewData) toTarget:self withObject:nil];

My parseNewData function (In AppDelegate)

-(void)parseNewData {

    //start network activity spinner and release controller when done
    RootViewController * root = [[RootViewController alloc] init];
    [root downloadIcon];
    [root release];

    //create pool to avoid memory leak
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];


    // get the XML path and start parsing
    NSURL *pathURL = [NSURL URLWithString:@"http://www.mysite.com/file.xml"];
    NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:pathURL];
    [parser setDelegate:self];
    [parser parse];

    //drain pool 
    [pool drain];
    [pool release];

}

Parser Did Finish (In AppDelegate)

- (void)parserDidEndDocument:(NSXMLParser *)parser
{

    // parser is finished, we can now kill the network activity icon on root view controller
    RootViewController * root = [[RootViewController alloc] init];
    [root killDownloadIcon];
    [root performSelectorOnMainThread:@selector(unhideShowtimesButton) withObject:nil waitUntilDone:NO];
    [root release];

}

My unhideShowtimesButton on ( in RootViewController )

-(void)unhideShowtimesButton {
    showtimesButton.hidden = FALSE;
}

I am making it to my unhideShowtimesButton (verified by break point) but its just completely ignoring the hidden = False.

Answer 1

You are creating a new RootViewController instance in each of the functions. This looks wrong. You should use only one instance throughout the code. My gut feel is that since the RootViewController instances are different, the showTimesButton instance that you are trying to hide is different from the one that is being shown.