Double-tap or two single-taps?

Question

What is the time limit for two taps to be considered a double-tap, on the iPhone OS?

// Edit: Why is this important?

In order to handle single-tap and double-tap differently, Apple's guide says to do performSelector...afterDelay with some 'reasonable' interval on first tap (and cancel it later if the second tap is detected).

The problem is that if the interval is too short (0.1), the single tap action will be performed even when double-tapping (if relying only on tapCount, that is). If it's too long (0.8), the user will be waiting unnecessarily for the single-tap to be recognized, when there is no possibility for a double-tap.

It has to be exactly the correct number, in order to work optimally, but definitely not smaller, or there's a chance for bugs (simultaneous single-tap and double-tap).

Answer 1

You can detect any number of tap by the tap gesture. No need of playing with NSTouches either. For all the user seeking for the solution here it is.

These simple lines of code does the duty of single and double tap functionality.

  UITapGestureRecognizer *doubleTapRecg = [[UITapGestureRecognizer alloc]
                                             initWithTarget:self 
                                             action:@selector(doubleTapped:)];
    doubleTapRecg.delegate = self;
    doubleTapRecg.numberOfTapsRequired = 2;
    doubleTapRecg.numberOfTouchesRequired = 1;
    [view addGestureRecognizer:doubleTapRecg];


    UITapGestureRecognizer *tapRecg = [[UITapGestureRecognizer alloc]
                                       initWithTarget:self 
                                       action:@selector(tapped:)];
    tapRecg.delegate = self;
    tapRecg.numberOfTapsRequired = 1;
    tapRecg.numberOfTouchesRequired = 1;
    [view addGestureRecognizer:tapRecg];
    [tapRecg requireGestureRecognizerToFail:doubleTapRecg];


    [doubleTapRecg release];
    [tapRecg release];