Physical interaction.
WHAT A FINGER IS
Imprecise, and it obscures what it touches.
WHAT THAT REQUIRES
Targets large enough to hit reliably Spacing so a near miss does not trigger something else Feedback confirming the touch registered
WHAT SIZE TO USE
The platform's recommended minimum, at least.
WHY
Below it, error rates rise sharply.
WHAT TO CONSIDER ABOUT REACH
Where the thumb comfortably reaches on a phone held in one hand.
WHERE THAT IS
The lower and middle portion of the screen.
WHAT THAT MEANS
Primary actions low and central, not in top corners.
WHAT DOES NOT EXIST ON TOUCH
Hover.
WHAT THAT RULES OUT
Anything revealed only on hover.
WHAT GESTURES TO USE
Those the platform already uses, so they are familiar.
WHAT TO AVOID
Custom gestures with no visible affordance Gestures conflicting with system ones Long press as the only route to an action
WHAT TO ALWAYS PROVIDE
A visible alternative to any gesture.
WHY
Undiscoverable gestures are undiscovered.
WHAT TO TEST
One-handed, on a real device, outdoors.
