getPreviousSibling method

RenderBox? getPreviousSibling({
  1. dynamic followPlaceHolder = true,
})

Implementation

RenderBox? getPreviousSibling({followPlaceHolder = true}) {
  RenderBoxModel renderBoxModel = this;
  RenderBox? previousSibling;
  RenderPositionPlaceholder? renderPositionPlaceholder = renderBoxModel.renderPositionPlaceholder;
  // It needs to find the previous sibling of the previous sibling if the placeholder of
  // positioned element exists and follows renderObject at the same time, eg.
  // <div style="position: relative"><div style="position: absolute" /></div>
  if (followPlaceHolder && renderPositionPlaceholder != null && renderPositionPlaceholder.parentData != null) {
    previousSibling = (renderPositionPlaceholder.parentData as ContainerParentDataMixin<RenderBox>).previousSibling;
    // The placeholder's previousSibling maybe the origin renderBox.
    if (previousSibling == renderBoxModel) {
      previousSibling = (renderBoxModel.parentData as ContainerParentDataMixin<RenderBox>).previousSibling;
    }
  } else {
    if (renderBoxModel.parentData != null) {
      previousSibling = (renderBoxModel.parentData as ContainerParentDataMixin<RenderBox>).previousSibling;
    }
  }
  return previousSibling;
}