Enabling Multi-Touch interaction in
UIView instances lets iOS recover and respond to more than one finger touch at a time. Set the
YES or override
isMultipleTouchEnabled for your view. When enabled, each touch callback returns an entire set of touches. When that set’s count exceeds 1, you know you’re dealing with Multi-Touch.
In theory, iOS supports an arbitrary number of touches. You can explore that limit by running Recipe 1-9 on an iPad, using as many fingers as possible at once. The practical upper limit has changed over time; this recipe modestly demurs from offering a specific number.
When Multi-Touch was first explored on the iPhone, developers did not dream ...