State.composite constructor

State.composite(
  1. StateKey key,
  2. InitialChild initialChild, {
  3. TransitionHandler? onEnter,
  4. TransitionHandler? onExit,
  5. MessageHandler? onMessage,
  6. required List<StateConfig> childStates,
  7. List<TreeStateFilter> filters = const [],
})

Constructs a composite state identified by key.

A composite state contains a number of childStates. When the composite state is entered, initialChild will be used to determine which if the child states to enter.

The behavior of the state can be customized by providing onMessage, onEnter, and onExit handler functions.

A list of filters can be provided in order to intercept the message and transition handlers of the state. The filters will be applied to the state in the order in which they appear in the list.

Implementation

factory State.composite(
  StateKey key,
  InitialChild initialChild, {
  TransitionHandler? onEnter,
  TransitionHandler? onExit,
  MessageHandler? onMessage,
  required List<StateConfig> childStates,
  List<TreeStateFilter> filters = const [],
}) =>
    State._((parent) {
      var childNodes = <TreeNodeInfo>[];
      var nodeInfo = InteriorNodeInfo(
        key,
        (_) => DelegatingTreeState(
          onMessage: onMessage,
          onEnter: onEnter,
          onExit: onExit,
        ),
        parent: parent,
        initialChild: initialChild.call,
        children: childNodes,
        filters: filters,
      );

      childNodes.addAll(childStates.map((e) => e.nodeInfo(nodeInfo)));

      return nodeInfo;
    });