findViewport static method

RenderViewportBase<ContainerParentDataMixin<RenderSliver>>? findViewport(
  1. RenderObject obj
)

Find out the viewport

Implementation

static RenderViewportBase? findViewport(RenderObject obj) {
  int maxCycleCount = 10;
  int currentCycleCount = 1;
  // Starting from flutter version 3.13.0, the type of parent received
  // is RenderObject, while the type of the previous version is AbstractNode,
  // but RenderObject is a subclass of AbstractNode, so for compatibility,
  // we can use RenderObject.
  var parent = obj.parent;
  if (parent is! RenderObject) {
    return null;
  }
  while (parent != null && currentCycleCount <= maxCycleCount) {
    if (parent is RenderViewportBase) {
      return parent;
    }
    parent = parent.parent;
    currentCycleCount++;
  }
  return null;
}