有没有办法暂停streambuilder并以编程方式启动它

Question

我有一个连接到 Algolia 以将数据带回我的搜索页面的流构建器，我的问题是，当它找到数据时，即使用户没有输入，它也会不断刷新结果，我认为这对于用户，我需要它在找到数据时暂停，仅在用户开始输入时刷新，以便用户有时间阅读他的结果

这是我的代码

StreamBuilder < List < AlgoliaObjectSnapshot >> (
    stream: Stream.fromFuture(_operation(_searchTerm)),
    builder: (context, snapshot) {
        if (!snapshot.hasData) return Text("Start Typing", style: TextStyle(color: Colors.white), );
        else {
            List < AlgoliaObjectSnapshot > currSearchStuff = snapshot.data;

            switch (snapshot.connectionState) {
                case ConnectionState.waiting:
                    return Container(child: CircularProgressIndicator());
                default:
                    if (snapshot.hasError)
                        return new Text('Error: ${snapshot.error}');
                    else
                        return CustomScrollView(shrinkWrap: true,
                            slivers: < Widget > [
                                SliverList(
                                    delegate: SliverChildBuilderDelegate(
                                        (context, index) {
                                            return _searchTerm.length > 0 ? DisplaySearchResult(artDes: currSearchStuff[index].data["name"], artistName: currSearchStuff[index].data["price"].toString(), genre: currSearchStuff[index].data["quantity"].toString(), ) :
                                                Container();

                                        },
                                        childCount: currSearchStuff.length ?? 0,
                                    ),
                                ),
                            ],
                        );


            }
        }


    }),

Answer 1

stream _yourSteam = Stream.fromFuture(_operation(_searchTerm)),
void pauseStream(){
_yourSteam.listen((event) { }).pause();
}

我从未使用过这种类型的流，但测试可能会回答

StreamBuilder < List < AlgoliaObjectSnapshot >> (
    stream: _yourSteam,
    builder: (context, snapshot) {
        if (!snapshot.hasData) return Text("Start Typing", style: TextStyle(color: Colors.white), );
        else {
            List < AlgoliaObjectSnapshot > currSearchStuff = snapshot.data;

            switch (snapshot.connectionState) {
                case ConnectionState.waiting:
                    return Container(child: CircularProgressIndicator());
                default:
                    if (snapshot.hasError)
                        return new Text('Error: ${snapshot.error}');
                    else
                        return CustomScrollView(shrinkWrap: true,
                            slivers: < Widget > [
                                SliverList(
                                    delegate: SliverChildBuilderDelegate(
                                        (context, index) {
                                            return _searchTerm.length > 0 ? DisplaySearchResult(artDes: currSearchStuff[index].data["name"], artistName: currSearchStuff[index].data["price"].toString(), genre: currSearchStuff[index].data["quantity"].toString(), ) :
                                                Container();

                                        },
                                        childCount: currSearchStuff.length ?? 0,
                                    ),
                                ),
                            ],
                        );


            }
        }


    }),

Answer 2

如果 algolia 在没有输入的情况下向您显示结果，则您必须控制结果的流式传输方式，即使您计划暂停流式传输，当您恢复流式传输时，一切都会完成（因为流式传输结果在暂停时被缓冲），我会这样接近它

class Search{
    bool _shouldEmit = true;

  void pause(){
    _shouldEmit = false;
  }
  void resume (){
    _shouldEmit = true;
  }
  
  Stream<dynamic> searchFor(String searchTerm) async*{
   final results = _operation(searchTerm);//your future operation
   await for(final result in results){
     if(_shouldEmit){
       yield result;
     }
   }
  }
}

这样使用

final mySearch = Search();
final theStream = mySearch.searchFor("keanu reeves");
///listen to the stream or pause when needed
mySearch.pause();