Requiring Gesture Recognizer Failures
In some cases, a gesture recognizer needs to fail in order to meet an app’s requirements. A great example is when a tap and a double tap need to work on the same view. By default, if a single-tap gesture recognizer and a double-tap gesture recognizer are attached to the same view, the single-tap recognizer will fire even if a double tap occurs—so both the single-tap and the double-tap target methods will get called. To see this in action, comment out the initial tap recognizer in viewDidLoad in the sample project.
/*UITapGestureRecognizer *tapRecognizer =[[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(myGestureViewTapped:)];[myGestureView addGestureRecognizer:tapRecognizer]; ...
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