handleLifecycleEvents method

@mustCallSuper void handleLifecycleEvents(List<LifecycleEvent> events)

Implementation

@mustCallSuper
void handleLifecycleEvents(List<LifecycleEvent> events) {
  if (_currentLifecycleState == events.last) {
    return;
  }

  List<LifecycleEvent> fixedEvents = events;

  // Ensures that [LifecycleEvent.inactive] and [LifecycleEvent.invisible]
  // occurs when single [LifecycleEvent.pop] triggered.
  // When an observed widget is removed from widget tree, this case happens.
  //
  // 对 events 进行修正，如果触发了[LifecycleEvent.pop]，确保[LifecycleEvent.inactive]
  // 和[LifecycleEvent.invisible]一定被触发。
  // 当widget被移除时，可能会发生这种情况。
  if (events.length == 1 &&
      events.first == LifecycleEvent.pop &&
      _currentLifecycleState != LifecycleEvent.push) {
    if (_currentLifecycleState!.index < LifecycleEvent.inactive.index) {
      fixedEvents = [
        LifecycleEvent.inactive,
        LifecycleEvent.invisible,
        LifecycleEvent.pop,
      ];
    } else if (_currentLifecycleState! == LifecycleEvent.inactive) {
      fixedEvents = [LifecycleEvent.invisible, LifecycleEvent.pop];
    }
  }

  // 分发 events
  for (LifecycleEvent event in fixedEvents) {
    if (event != _currentLifecycleState) {
      _currentLifecycleState = event;
      onLifecycleEvent(event);
    }
  }
}