onSingleTap

onSingleTap is a term used in user interface programming to describe a callback or handler that responds to a single-tap gesture. The exact API and naming vary by framework, but the core idea is to trigger an action when the user taps once and releases without initiating a second tap.

In Android, gesture detection is commonly implemented with a GestureDetector. The interface GestureDetector.OnGestureListener includes onSingleTapUp(MotionEvent e), which fires when the user performs a tap and lifts the finger. Some applications also listen for a true single-tap event using OnDoubleTapListener’s onSingleTapConfirmed(MotionEvent e); this callback runs only if a second tap does not occur within the double-tap interval, ensuring the gesture is definitively a single tap.

In other platforms, the concept appears under different names. For example, iOS uses a UITapGestureRecognizer configured with numberOfTapsRequired = 1 to handle single taps; the action is tied to a selector rather than a method named onSingleTap. The exact event lifecycle and latency can differ: onSingleTapUp tends to happen promptly at lift, while onSingleTapConfirmed introduces a short delay to distinguish from double taps.

Usage considerations include balancing responsiveness with accuracy. If a framework distinguishes between onSingleTapUp and onSingleTapConfirmed, choosing the right callback affects perceived latency. Developers should account for interaction patterns, ensure the gesture does not conflict with scrolling or other gestures, and tailor hit-testing and thresholds to the target platform.

See also: gesture detectors, double-tap, tap gesture, onSingleTapUp, onSingleTapConfirmed, UITapGestureRecognizer.