setCanDrag method

Implementation

@override
@protected
void setCanDrag(bool value) {
  if (value == _lastCanDrag && (!value || widget.axis == _lastAxisDirection)) {
    return;
  }
  if (!value) {
    _gestureRecognizers = const <Type, GestureRecognizerFactory>{};
    // Cancel the active hold/drag (if any) because the gesture recognizers
    // will soon be disposed by our RawGestureDetector, and we won't be
    // receiving pointer up events to cancel the hold/drag.
    _handleDragCancel();
  } else {
    switch (widget.axis) {
      case Axis.vertical:
        _gestureRecognizers = <Type, GestureRecognizerFactory>{
          VerticalDragGestureRecognizer:
              GestureRecognizerFactoryWithHandlers<VerticalDragGestureRecognizer>(
                () => VerticalDragGestureRecognizer(supportedDevices: _configuration.dragDevices),
                (VerticalDragGestureRecognizer instance) {
                  instance
                    ..onDown = _handleDragDown
                    ..onStart = _handleDragStart
                    ..onUpdate = _handleDragUpdate
                    ..onEnd = _handleDragEnd
                    ..onCancel = _handleDragCancel
                    ..minFlingDistance = _physics?.minFlingDistance
                    ..minFlingVelocity = _physics?.minFlingVelocity
                    ..maxFlingVelocity = _physics?.maxFlingVelocity
                    ..velocityTrackerBuilder = _configuration.velocityTrackerBuilder(context)
                    ..dragStartBehavior = widget.dragStartBehavior
                    ..multitouchDragStrategy = _configuration.getMultitouchDragStrategy(context)
                    ..gestureSettings = _mediaQueryGestureSettings
                    ..supportedDevices = _configuration.dragDevices;
                },
              ),
        };
      case Axis.horizontal:
        _gestureRecognizers = <Type, GestureRecognizerFactory>{
          HorizontalDragGestureRecognizer:
              GestureRecognizerFactoryWithHandlers<HorizontalDragGestureRecognizer>(
                () =>
                    HorizontalDragGestureRecognizer(supportedDevices: _configuration.dragDevices),
                (HorizontalDragGestureRecognizer instance) {
                  instance
                    ..onDown = _handleDragDown
                    ..onStart = _handleDragStart
                    ..onUpdate = _handleDragUpdate
                    ..onEnd = _handleDragEnd
                    ..onCancel = _handleDragCancel
                    ..minFlingDistance = _physics?.minFlingDistance
                    ..minFlingVelocity = _physics?.minFlingVelocity
                    ..maxFlingVelocity = _physics?.maxFlingVelocity
                    ..velocityTrackerBuilder = _configuration.velocityTrackerBuilder(context)
                    ..dragStartBehavior = widget.dragStartBehavior
                    ..multitouchDragStrategy = _configuration.getMultitouchDragStrategy(context)
                    ..gestureSettings = _mediaQueryGestureSettings
                    ..supportedDevices = _configuration.dragDevices;
                },
              ),
        };
    }
  }
  _lastCanDrag = value;
  _lastAxisDirection = widget.axis;
  if (_gestureDetectorKey.currentState != null) {
    _gestureDetectorKey.currentState!.replaceGestureRecognizers(_gestureRecognizers);
  }
}