a loop in own Thread

I want to show some picture with a waiting of 2sec before showing the other. So i tried to do it with the good old C99 : sleep(300) but the UI does not update.

The second thing I tried was: 1. create the method in his own thread

[NSThread detachNewThreadSelector:@selector(gameIt) toTar开发者_开发问答get:self withObject:nil]; 

1. Then sleep in the Method with:

   [NSThread sleepForTimeInterval:1];

But the same problem, the UI does not update. What do I make wrong? Please help me. Thank you.

Anytime you sleep on the main thread, you will stall the UI.

You may have some luck with NSThread's class method scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:. You'll have to keep some context so that each invocation of your method will know what to do, but this will not stall your UI and it will give you the 3 second (or whatever) interval you're looking for.

Run your processing on the background thread, but when you edit the UI you need to performSelectorOnMainThread

[view performSelectorOnMainThread:@selector(setNeedsDisplay) withObject:nil waitUntilDone:YES];