All 7 Flutter Gestures & Touch Handling questions
More in Flutter Gestures & Touch Handling
What is the difference between GestureDetector and InkWell, and when would you specifically choose InkWell instead, particularly for a Material Design styled interactive element? How does the gesture arena in Flutter resolve genuine ambiguity when several different overlapping widgets, or several different possible gesture types on exactly the same widget, could all potentially claim to actually recognize and handle the exact same specific touch input event? How do you properly implement a custom swipeable card interface, such as the classic swipe left or swipe right pattern popularized by many dating apps, using Draggable or a raw GestureDetector combined with an AnimationController? How do you properly detect and respond to multi touch gestures in Flutter, such as pinch to zoom or a two finger rotation gesture, using the ScaleGestureRecognizer or the InteractiveViewer widget? How can you properly implement a genuinely custom gesture recognizer in Flutter when none of the existing built in gesture recognizers, such as tap, drag, or scale, actually adequately capture the exact very specific interaction pattern your particular app genuinely needs? What performance considerations become genuinely important when handling a very high frequency of continuous gesture events, such as a genuinely fast, continuous freehand drawing gesture, without noticeably introducing visible lag or dropped frames?
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Flutter › Flutter Gestures & Touch Handling

What is the GestureDetector widget in Flutter, and how does it let you detect common touch interactions, such as a tap, a double tap, or a long press, on any given widget?

Beginner

Answer

GestureDetector is a genuinely versatile widget that wraps around any other child widget and listens for a wide variety of common touch interactions, including a simple tap, a double tap, a long press, and various different drag gestures, letting you attach specific callback functions that automatically get called the moment each particular corresponding gesture is actually detected, and this makes it possible to add meaningful interactivity to essentially any visual widget, including ones like a plain Container or an Image that do not otherwise have any built in interactive tap behavior of their own.
GestureDetector(
  onTap: () => print('Tapped!'),
  onLongPress: () => print('Long pressed!'),
  child: Container(color: Colors.blue, width: 100, height: 100),
)
Real-world example A photo gallery app wraps each individual thumbnail image with a GestureDetector, opening that specific photo in full screen view on a regular single tap, while showing a context menu with additional sharing and deletion options specifically on a long press instead.

Common follow-ups: What is the difference between GestureDetector and the simpler InkWell widget?;Can a single GestureDetector actually detect several different gesture types simultaneously on exactly the same widget?

Flutter Widgets Fundamentals (Stateless & Stateful);Custom Widgets & Reusable Components
All 7 Flutter Gestures & Touch Handling questions