Refresh view with display and setNeedsDisplay not working

I am having problems updating my customView object during simulation. The window pops up after the simulation is done. I would like it to update itself during the simulation. For this I use setNeedsDisplay:YES and I have also tried display. None of this works for me however. Does anyone have an idea how I should get this working? As you can see below I have tried to create a new thread for the updating as well as using NSOperations. Grateful for help!

//Run simulation
    for (int iteration=0; iteration<numberOfIterations; iteration++){
        //NSInvocationOperation *update = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(updatePopulation) object:nil];
        //NSInvocationOperation *draw = [[NSInvocationOperation alloc] initWithTarget:view selector:@selector(redraw) object:nil];
        //[draw addDependency:update];
        //[queue addOperation:update];
        //[queue addOperation:draw];
        [NSThread sleepForTimeInterval:0.01]; //to make it easer to see..
        [self updatePopulation];
        //[view redraw];
        [NSThread detachNewThreadSelector:@selector(redraw) toTarget:view withObject:nil];
        //[self performSelector:@selector(updatePopulation) withObject:nil afterDelay:1];
        //[view performSelector:@selector(redraw) withObject:nil afterDelay:1];
        //Save segregation
        if (iteration%(numberOfIterations/100) == 0) {
            printf("hej\n");
        }
    }

in my viewer class:

- (void) redraw {
    //[self setNeedsDisplay:YES];
    [self display];开发者_如何学JAVA
}

It looks like you are trying to do the painting on the worker thread.

This is not, as far as I am aware, supported.

To solve this, you need to move your simulation to a worker thread, and then use performSelectorOnMainThread: to invoke the redraw on the main thread. I find this article on threading in cocoa to be required reading when trying to implemented threaded cocoa apps.