如何基于两个Firestore集合构建Flutter小部件 [英] How to build Flutter widget based on two Firestore collections

问题描述

我在Firestore中有两个收藏夹:

I have two collections in Firestore:

事件:
标题
coachId

events:
title
coachId

教练:
名称

coaches:
name

我用StreamBuilder创建了一个小部件"EventsPage"，用于显示事件.现在，我需要该小部件来显示每个事件的教练名称-像coachs [event ['coachId'] ['name']之类的东西.在构建"EventsPage"小部件之前，如何获取"coachs"集合?

I made a widget 'EventsPage' with StreamBuilder which shows events. Now I need this widget to show coach name for every event - something like coaches[event['coachId']['name']. How can I get 'coaches' collection before 'EventsPage' widget is built?

推荐答案

您可以使用嵌套的StreamBuilder s

You can use nested StreamBuilders

Widget nestedStreamBuilders() {
  return StreamBuilder(
    stream: firstStream,
    builder: (BuildContext context, AsyncSnapshot snapshot) {
      if (snapshot.hasError) return Text('Error: ${snapshot.error}');
      switch (snapshot.connectionState) {
        case ConnectionState.none:
          return Text('Select lot');
        case ConnectionState.waiting:
          return Text('Awaiting bids...');
        case ConnectionState.active:
        case ConnectionState.done:
          return StreamBuilder(
            stream: secondStream,
            builder: (BuildContext context, AsyncSnapshot secondSnapshot) {
              if (secondSnapshot.hasError)
                return Text('Error: ${secondSnapshot.error}');
              switch (secondSnapshot.connectionState) {
                case ConnectionState.none:
                  return Text('Select lot');
                case ConnectionState.waiting:
                  return Text('Awaiting bids...');
                case ConnectionState.active:
                case ConnectionState.done:
                  return BuildYourWidgetHere();
                  // you can build your widget here because we have the both data 
              return null; // unreachable
            },
          );
      }
      return null; // unreachable
    },
  );
}

如果您需要FutureBuilder，请参见以下示例: FutureBuilder_Example

if you need FutureBuilder this is the example : FutureBuilder_Example

这篇关于如何基于两个Firestore集合构建Flutter小部件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！