How to force a view to render itself?

Question

In my app I have a number of small subviews. When the user taps a subview, I place one separate view over top of the tapped subview (same size) and then animate this separa

Answer 1

As I commented above, Joe asked something similar (as a more general question) here, to which Tom Swift provided an answer that manipulates the current run loop.

His suggestion was to force the run loop through one iteration immediately after you call -setNeedsDisplay using the following code:

[[NSRunLoop currentRunLoop] runMode: NSDefaultRunLoopMode beforeDate: [NSDate date]];

There are some caveats to this approach, which are discussed in the comments there.

Also, it was pointed out there that

[CATransaction flush];

may also achieve the same effect of forcing an immediate redraw of the view.