UIPinchGestureRecognizer require two touches

Question

I have added the following gesture recognizers to a view:

UIPinchGestureRecognizer *pch= [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(ViewPinching:)];
[[self view] addGestureRecognizer:pch];

// and

UIPanGestureRecognizer *d = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(ViewDragging:)];
[d setMinimumNumberOfTouches:4];
[[self view] addGestureRecognizer:d];

I want to fire the event when 4 fingers are dragged and when I do that the Pinch gesture recognizer fires instead of the Pan gesture recognizer. I was thinking that maybe I could fix this problem if I restrict the UIPinchGestureRecognizer to be fired only if touches.count=2

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I don't know if this will be practical or not. Maybe I could add:

 UIPinchGestureRecognizer *pch= [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(ViewPinching:)];
[[self view] addGestureRecognizer:pch];

every time touches start if there is two touches I will add that event and remove it ontouchesended.

Bad idea: 4 fingers is a multitasking gesture that will close your app on iOS 5 — CodaFi
true. how can I restrict it so that it only works with 2 fingers and 4 or more then... — Tono Nam
Nope. You'll need your own subclass of UIGestureRecognizer, as UIPinchGestureRecognizer only responds to 2 or 1 finger touches (any more are ignored). — CodaFi

CodaFi CodaFi · Accepted Answer · 2012-05-04T02:56:58

This is ultimately a bad idea. A 4-finger pinch in iOS 5 will close your app, and a 4 finger pan will switch to the next app (obviously not good for UX). If you absolutely must use 4 fingers, make a subclass of UIGestureRecognizer and do the pinching logic yourself. Let me apologize ahead of time for not having an example, as your use case is quite unique.

UIPinchGestureRecognizer require two touches

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1 Answers