Flutter Streambuilder 不断重建

Question

我有一个流构建器在监听 Firestore，它有点工作。主要问题是streambuilder不断重建（如果它不花费我额外的读取，那么不用担心，但如果它这样做了，那么这是一个我假设它确实存在的问题）。当主页第一次构建时，当我转到另一个页面时，它会再次构建，当我弹回主页时，它会第三次重建。

代码：

class _RequestsListState extends State<RequestsList> with AutomaticKeepAliveClientMixin {
  final Map<String, List<Post>> posts = {};
  final List<String> postsUserIDs = [];

  @override
  bool get wantKeepAlive => true;

  @override
  Widget build(BuildContext context) {
    super.build(context);

    print('RequestsList');
    User cUser = InheritedUser.of(context).user;

    return StreamBuilder<List<Post>>(
        initialData: cUser.posts,
        stream: APIs().posts.auPostsStream(cUserID: cUser.userID),
        builder: (context, snap) {
          if (snap.hasError) {
            print('AUPostsList.dart StreamBuilder Error: ${snap.error}');
            return null;
          } else {

            print('POSTS LENGTH');
            print(snap.connectionState);
            print(cUser.posts.length);

            this.posts.clear();
            this.postsUserIDs.clear();

            snap.data.forEach((post) {
              if (this.posts[post.user.documentID] == null) {
                this.posts[post.user.documentID] = [post];
              } else {
                this.posts[post.user.documentID].add(post);
              }

              if (!this.postsUserIDs.contains(post.user.documentID)) {
                this.postsUserIDs.add(post.user.documentID);
              }
            });

            return ListView.separated(
                controller: widget.scrollController,
                physics: BouncingScrollPhysics(),
                shrinkWrap: true,
                padding: EdgeInsets.only(top: 0.0),
                itemBuilder: (context, index) => RequestItem(posts: this.posts[this.postsUserIDs[index]]),
                separatorBuilder: (context, index) => Container(),
                itemCount: this.postsUserIDs.length);
          }
        });
  }
}

其次，当我转到第二页时，数组被清空。我没有在任何地方清除它，所以我不确定为什么它在点击一个项目后清空数组......

日志：

Reloaded 0 of 773 
libraries in 169ms.
flutter: ChatsList
flutter: RequestsList
flutter: POSTS LENGTH
flutter: ConnectionState.waiting
flutter: 1
flutter: RequestsList
flutter: POSTS LENGTH
flutter: ConnectionState.waiting
flutter: 0
flutter: ChatsList
flutter: RequestsList
flutter: POSTS LENGTH
flutter: ConnectionState.waiting
flutter: 0
flutter: ChatsList

Answer 1

我知道这已经晚了，但是使用 init 方法或使用提供程序在服务文件中进行调用将流移出构建上下文是我进行设置的方式。让我知道你是否来对了。