flutter_tracker/lib/pages/track_page.dart

import 'package:flutter/material.dart';
import 'package:flutter_blue/flutter_blue.dart';
import 'package:flutter_tracker/dio/track_dao.dart';
import 'package:flutter_tracker/model/user_model.dart';
import 'package:flutter_tracker/views/contact_card.dart';
import 'package:nearby_connections/nearby_connections.dart';
import 'package:shared_preferences/shared_preferences.dart';

import 'bluetooth_off_page.dart';

/// Description:
/// Time       : 2021年12月03日 Friday
/// Author     : liuyuqi.gov@msncn
class TrackPage extends StatefulWidget {
  const TrackPage({Key key}) : super(key: key);

  @override
  _TrackPageState createState() => _TrackPageState();
}

class _TrackPageState extends State<TrackPage> {
  String testText = '';
  final Strategy strategy = Strategy.P2P_STAR;
  UserModel currentUser;
  List<UserModel> blueList = [];
  List<BluetoothDevice> devices = [];
  List<ScanResult> myScanResult = [];
  List<String> updateTime = [];

  List<UserModel> users = [];
  FlutterBlue flutterBlue = FlutterBlue.instance;

  @override
  Widget build(BuildContext context) {
    return StreamBuilder<BluetoothState>(
        stream: FlutterBlue.instance.state,
        initialData: BluetoothState.unknown,
        builder: (c, snapshot) {
          final state = snapshot.data;
          if (state == BluetoothState.on) {
            return buildContent();
          }
          return BluetoothOffPage(state: state);
        });
  }

  Column buildContent() {
    return Column(
      children: <Widget>[
        Expanded(
          child: Padding(
            padding: const EdgeInsets.only(
              left: 25.0,
              right: 25.0,
              bottom: 10.0,
              top: 30.0,
            ),
            child: Container(
              height: 50.0,
              width: double.infinity,
              decoration: BoxDecoration(
                color: Colors.deepPurple[500],
                borderRadius: BorderRadius.circular(20.0),
                boxShadow: const [
                  BoxShadow(
                    color: Colors.black,
                    blurRadius: 4.0,
                    spreadRadius: 0.0,
                    offset: Offset(2.0, 2.0), // shadow direction: bottom right
                  )
                ],
              ),
              child: Row(
                children: const <Widget>[
                  Expanded(
                    child: Image(
                      image: AssetImage('assets/images/corona.png'),
                    ),
                  ),
                  Expanded(
                    flex: 2,
                    child: Text(
                      '附近用户',
                      textAlign: TextAlign.left,
                      style: TextStyle(
                        fontSize: 21.0,
                        color: Colors.white,
                        fontWeight: FontWeight.w500,
                      ),
                    ),
                  )
                ],
              ),
            ),
          ),
        ),
        buildStartButton(),
        Expanded(
          flex: 2,
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 25.0),
            child: buildListView(),
          ),
        ),
      ],
    );
  }

  Widget buildListView() {
    if (blueList.isNotEmpty) {
      return ListView.builder(
        itemBuilder: (context, index) {
          return ContactCard(
            imagePath: 'assets/images/green.jpg',
            infection: '健康',
            username: "李四",
            updateTime: updateTime[index],
            deviceid: blueList[index].deviceid,
          );
        },
        itemCount: blueList.length,
      );
    } else {
      return Text("");
    }
  }

  StreamBuilder<bool> buildStartButton() {
    return StreamBuilder<bool>(
        stream: flutterBlue.isScanning,
        initialData: false,
        builder: (context, snapshot) {
          if (snapshot.data) {
            return Padding(
              padding: EdgeInsets.only(bottom: 200.0),
              child: RaisedButton(
                shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(20.0)),
                elevation: 5.0,
                color: Colors.red,
                onPressed: () async {
                  startTrack(snapshot.data);
                },
                child: const Text(
                  '停止追踪',
                  style: TextStyle(
                    fontSize: 20.0,
                    fontWeight: FontWeight.bold,
                    color: Colors.white,
                  ),
                ),
              ),
            );
          } else {
            return Padding(
              padding: EdgeInsets.only(bottom: 200.0),
              child: RaisedButton(
                shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(20.0)),
                elevation: 5.0,
                color: Colors.deepPurple[400],
                onPressed: () async {
                  startTrack(snapshot.data);
                },
                child: const Text(
                  '开始追踪',
                  style: TextStyle(
                    fontSize: 20.0,
                    fontWeight: FontWeight.bold,
                    color: Colors.white,
                  ),
                ),
              ),
            );
          }
        });
  }

  @override
  void initState() {
    super.initState();
    addContactsToList();
    getPermissions();
  }

  void discovery() async {
    try {
      bool a = await Nearby().startDiscovery(currentUser.username, strategy,
          onEndpointFound: (id, name, serviceId) async {
        // 保存数据
      }, onEndpointLost: (id) {
        print(id);
      });
      print('DISCOVERING: ${a.toString()}');
    } catch (e) {
      print(e);
    }
  }

  void getPermissions() async {
    Nearby().askLocationAndExternalStoragePermission();
  }

  Future<void> getCurrentUser() async {
    SharedPreferences sharedPreferences = await SharedPreferences.getInstance();
    UserModel user = sharedPreferences.get("user");
  }

  void addContactsToList() async {
    await getCurrentUser();
    //  服务器获取当前用户数据
    SharedPreferences sharedPreferences = await SharedPreferences.getInstance();
    String token = sharedPreferences.getString("token");
    setState(() async {
      users = await TrackDao.getContactList(token);
    });
  }

  void startTrack(bool flag) async {
    try {
      bool a = await Nearby().startAdvertising(
        currentUser.username,
        strategy,
        onConnectionInitiated: null,
        onConnectionResult: (id, status) {
          print(status);
        },
        onDisconnected: (id) {
          print('Disconnected $id');
        },
      );
      // 上传追踪数据
      SharedPreferences sharedPreferences =
          await SharedPreferences.getInstance();
      String token = sharedPreferences.getString("token");
      TrackDao.uploadContact(token);
      print('ADVERTISING ${a.toString()}');
    } catch (e) {
      print(e);
    }
    discovery();
  }
}