Flutter AWS AppSync订阅功能插件aws_appsync_subscription的使用

该插件用于处理与AWS AppSync订阅的连接。

开始使用

在你的项目 pubspec.yaml 文件中添加以下依赖：

dependencies:
  appsync_subscription: ^1.0.1

然后运行 flutter pub get 来安装依赖。

使用示例

首先，在 Dart 文件中导入插件包：

import 'package:appsync_subscription/appsync_subscription.dart';

接下来，创建一个简单的 Flutter 应用并实现订阅功能。以下是一个完整的示例代码：

import 'package:flutter/material.dart';
import 'package:appsync_subscription/appsync_subscription.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  [@override](/user/override)
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final endPoint = "https://yourappsync.appsync-api.region.amazonaws.com/graphql";
  final apiKey = "your-api-key";
  final port = 443;
  final _appsyncSubscription = Subscription(endPoint, apiKey, port);

  [@override](/user/override)
  void initState() {
    super.initState();
    final query = {
      'query': '''subscription {
          onPublishResult(id: "12345") {
            id
          }
        }
        '''
    };
    _appsyncSubscription.subscribeToSubscription(query, _callBackFunc);
  }

  void _callBackFunc(data) {
    print('Data received from subscription $data');
    // 更新界面数据
    setState(() {});
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("AppSync 订阅示例"),
      ),
      body: Center(
        child: Text("等待接收数据..."),
      ),
    );
  }
}

代码解释

1. 导入库：

   import 'package:appsync_subscription/appsync_subscription.dart';
   

2. 初始化参数：

   final endPoint = "https://yourappsync.appsync-api.region.amazonaws.com/graphql";
   final apiKey = "your-api-key";
   final port = 443;
   final _appsyncSubscription = Subscription(endPoint, apiKey, port);
   

3. 订阅逻辑：

   [@override](/user/override)
   void initState() {
     super.initState();
     final query = {
       'query': '''subscription {
           onPublishResult(id: "12345") {
             id
           }
         }
         '''
     };
     _appsyncSubscription.subscribeToSubscription(query, _callBackFunc);
   }
   

4. 回调函数：

   void _callBackFunc(data) {
     print('Data received from subscription $data');
     // 更新界面数据
     setState(() {});
   }