didAdd method

Implementation

@protected
@mustCallSuper
void didAdd() {
  if (requestFocus) {
    // This TickerFuture serves two purposes. First, we want to make sure that
    // animations triggered by other operations will finish before focusing
    // the navigator. Second, navigator.focusNode might acquire more focused
    // children in Route.install asynchronously. This TickerFuture will wait
    // for it to finish first.
    //
    // The later case can be found when subclasses manage their own focus scopes.
    // For example, ModalRoute creates a focus scope in its overlay entries. The
    // focused child can only be attached to navigator after initState which
    // will be guarded by the asynchronous gap.
    TickerFuture.complete().then<void>((void _) {
      // The route can be disposed before the ticker future completes. This can
      // happen when the navigator is under a TabView that warps from one tab to
      // another, non-adjacent tab, with an animation. The TabView reorders its
      // children before and after the warping completes, and that causes its
      // children to be built and disposed within the same frame. If one of its
      // children contains a navigator, the routes in that navigator are also
      // added and disposed within that frame.
      //
      // Since the reference to the navigator will be set to null after it is
      // disposed, we have to do a null-safe operation in case that happens
      // within the same frame when it is added.
      navigator?.focusNode.enclosingScope?.requestFocus();
    });
  }
}