correctBy method Null safety
- double correction
override
Apply a layout-time correction to the scroll offset.
This method should change the pixels value by correction, but without
calling notifyListeners. It is called during layout by the
RenderViewport, before applyContentDimensions. After this method is
called, the layout will be recomputed and that may result in this method
being called again, though this should be very rare.
See also:
- jumpTo, for also changing the scroll position when not in layout. jumpTo applies the change immediately and notifies its listeners.
- correctPixels, which is used by the ScrollPosition itself to set the offset initially during construction or after applyViewportDimension or applyContentDimensions is called.
Implementation
@override
void correctBy(double correction) {
assert(
hasPixels,
'An initial pixels value must exist by calling correctPixels on the ScrollPosition',
);
_pixels = _pixels! + correction;
_didChangeViewportDimensionOrReceiveCorrection = true;
}