Elegant way to implement press and hold continuous event firing? - objective-c

Question

I often have a need to fire a sequence of events as a result of holding down a button. Think of a + button that increments a field: tapping it should increment it by 1, but tap & hold should say increment this by 1 every second until the button is released. Another example is the scrubbing function when holding down the backwards or forwards button in an audio player type app.
I usually resort to the following strategy:
On touchDownInside I set up a repeating timer with my desired interval.
On touchUpInside I invalidate and release the timer.
But for every such button I need a separate timer instance variable, and 2 target-actions, and 2 method implementations. (This is assuming I'm writing a generic class and don't want to impose restrictions on the max number of simultaneous touches).
Is there a more elegant way to solve this that I'm missing?

Answer 1

Register the events for every button by:
[button addTarget:self action:#selector(touchDown:withEvent:) forControlEvents:UIControlEventTouchDown];
[button addTarget:self action:#selector(touchUpInside:withEvent:) forControlEvents:UIControlEventTouchUpInside];
For each button, set the tag attribute:
button.tag = 1; // 2, 3, 4 ... etc
In the handler, do whatever you need. Identify a button by the tag:
- (IBAction) touchDown:(Button *)button withEvent:(UIEvent *) event
{
NSLog("%d", button.tag);
}

Answer 2

I suggest UILongPressGestureRecognizer.
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(addOpenInService:)];
longPress.delegate = self;
longPress.minimumPressDuration = 0.7;
[aView addGestureRecognizer:longPress];
[longPress release];
longPress = nil;
On firing the event, you can get the call in
- (void) addOpenInService: (UILongPressGestureRecognizer *) objRecognizer
{
// Do Something
}
Likewise you can use UITapGestureRecognizer for recognizing user taps.
Hope this helps. :)