How to delay while retaining a responsive GUI on Cocoa Touch?

Basically, I have an array of buttons I want to iterate and highlight (among other things) one after another, with a delay in-between. Seems like an easy task, but I can't seem to manage to get it to work cleanly while still being responsive.

I started out with this:

for MyButton *button in buttons {
    [button highlight];
    [button doStuff];
    usleep(800000); // Wait 800 milliseconds.
}

But it is unresponsive, so I tried using the run loop instead.

void delayWithRunLoop(NSTimeInterval interval)
{
    NSDate *date = [NSDate dateWithTimeIntervalSinceNow:interval];开发者_JAVA百科
    [[NSRunLoop currentRunLoop] runUntilDate:date];
}

for MyButton *button in buttons {
    [button highlight];
    [button doStuff];
    delayWithRunLoop(0.8); // Wait 800 milliseconds.
}

However, it is also unresponsive.

Is there any reasonable way to do this? It seems cumbersome to use threads or NSTimers.

NSTimer will be perfect for this task.

The timer's action will fire ever x seconds, where x is what you specify.

The salient point is that this doesn't block the thread it runs on. As Peter said in the comments for this answer, I was incorrect in saying the timer waits on a separate thread. See the link in the comment for details.

Nevermind, Jasarien was right, NSTimer is perfectly suitable.

- (void)tapButtons:(NSArray *)buttons
{
    const NSTimeInterval waitInterval = 0.5; // Wait 500 milliseconds between each button.
    NSTimeInterval nextInterval = waitInterval;
    for (MyButton *button in buttons) {
        [NSTimer scheduledTimerWithTimeInterval:nextInterval
                                         target:self
                                       selector:@selector(tapButtonForTimer:)
                                       userInfo:button
                                        repeats:NO];
        nextInterval += waitInterval;
    }
}

- (void)tapButtonForTimer:(NSTimer *)timer
{
    MyButton *button = [timer userInfo];
    [button highlight];
    [button doStuff];
}