UIProgressView not updated

I have a UIProgressView that I am trying to change the progress but is is never upd开发者_如何学编程ated. My "slow" operation is done from a NSoperation/NSOperation queue so it should be multithreaded.

Did you already experienced this or do you have any idea to solve this?

Thanks :)

---

Updates to the user interface should usually be done on the main thread. Try using -performSelectorOnMainThread:withObject:waitUntilDone: to update your UIProgressView.