contact_tracing/lib/main.dart

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import 'package:flutter_sms/flutter_sms.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:flutter_vibrate/flutter_vibrate.dart';

void main() {
  runApp(const AnalyzeView());
}

class AnalyzeView extends StatefulWidget {
  const AnalyzeView({Key? key}) : super(key: key);

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

class AnalyzeViewState extends State<AnalyzeView>
    with SingleTickerProviderStateMixin {
  String? barcode;
  double peopleCount = 1;
  final String prefix = 'smsto:1922:';

  MobileScannerController controller = MobileScannerController(
    torchEnabled: false,
    facing: CameraFacing.back,
  );

  void _sendSMS(String message, List<String> recipents) async {
    if (await Vibrate.canVibrate) {
      Vibrate.vibrate();
    }
    var status = await Permission.sms.status;
    if (status.isDenied) {
      Map<Permission, PermissionStatus> statuses = await [
        Permission.sms,
      ].request();
    }
    String _result =
        await sendSMS(message: message, recipients: recipents, sendDirect: true)
            .catchError((onError) {
      if (kDebugMode) {
        print('sms err: $onError');
      }
    });
    if (kDebugMode) {
      print('sms res: $_result');
    }
    await sendSMS(message: '', recipients: recipents, sendDirect: false);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.black,
        body: Builder(builder: (context) {
          return Stack(
            children: [
              Align(
                alignment: Alignment.center,
                child: Container(
                  width: MediaQuery.of(context).size.width - 100,
                  color: Colors.black.withOpacity(0.0),
                  child: MobileScanner(
                      controller: controller,
                      fit: BoxFit.contain,
                      onDetect: (barcode, args) {
                        if (this.barcode != barcode.rawValue) {
                          setState(() {
                            this.barcode = barcode.rawValue;
                          });
                          String msg = barcode.rawValue.toLowerCase();
                          if (msg.startsWith(prefix)) {
                            List<String> recipents = ['1922'];
                            msg = msg.substring(prefix.length);
                            if (peopleCount > 1) {
                              msg += ' +${peopleCount.toInt() - 1}';
                            }
                            _sendSMS(msg, recipents);
                          }
                        }
                      }),
                ),
              ),

              Align(
                alignment: Alignment.bottomCenter,
                child: Container(
                    alignment: Alignment.bottomCenter,
                    height: 150,
                    color: Colors.black.withOpacity(0.4),
                    child: Column(
                      children: [
                        Row(
                          crossAxisAlignment: CrossAxisAlignment.center,
                          children: [
                            Center(
                              child: SizedBox(
                                width: MediaQuery.of(context).size.width,
                                height: 80,
                                child: FittedBox(
                                  child: Slider(
                                      value: peopleCount,
                                      min: 1,
                                      max: 10,
                                      divisions: 9,
                                      label: 'People: ${peopleCount.toInt()}',
                                      onChanged: (v) {
                                        setState(() {
                                          peopleCount = v;
                                        });
                                      }),
                                ),
                              ),
                            ),
                          ],
                        ),
                        Row(
                          crossAxisAlignment: CrossAxisAlignment.center,
                          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                          children: [
                            IconButton(
                              color: Colors.white,
                              icon: ValueListenableBuilder(
                                valueListenable: controller.torchState,
                                builder: (context, state, child) {
                                  switch (state as TorchState) {
                                    case TorchState.off:
                                      return const Icon(Icons.flash_off,
                                          color: Colors.grey);
                                    case TorchState.on:
                                      return const Icon(Icons.flash_on,
                                          color: Colors.yellow);
                                  }
                                },
                              ),
                              iconSize: 32.0,
                              onPressed: () => controller.toggleTorch(),
                            ),
                            Center(
                              child: SizedBox(
                                width: MediaQuery.of(context).size.width - 220,
                                height: 50,
                                child: FittedBox(
                                  child: Text(
                                    barcode ?? 'Scan something!',
                                    overflow: TextOverflow.fade,
                                    style: Theme.of(context)
                                        .textTheme
                                        .headlineSmall!
                                        .copyWith(color: Colors.white),
                                  ),
                                ),
                              ),
                            ),
                            IconButton(
                              color: Colors.white,
                              icon: ValueListenableBuilder(
                                valueListenable: controller.cameraFacingState,
                                builder: (context, state, child) {
                                  switch (state as CameraFacing) {
                                    case CameraFacing.front:
                                      return const Icon(Icons.camera_front);
                                    case CameraFacing.back:
                                      return const Icon(Icons.camera_rear);
                                  }
                                },
                              ),
                              iconSize: 32.0,
                              onPressed: () => controller.switchCamera(),
                            ),
                          ],
                        ),
                      ],
                    )),
              ),

              // Container(
              //   alignment: Alignment.bottomCenter,
              //   margin: EdgeInsets.only(bottom: 80.0),
              //   child: IconButton(
              //     icon: ValueListenableBuilder(
              //       valueListenable: cameraController.torchState,
              //       builder: (context, state, child) {
              //         final color =
              //             state == TorchState.off ? Colors.grey : Colors.white;
              //         return Icon(Icons.bolt, color: color);
              //       },
              //     ),
              //     iconSize: 32.0,
              //     onPressed: () => cameraController.torch(),
              //   ),
              // ),
            ],
          );
        }),
      ),
    );
  }

  @override
  void dispose() {
    // cameraController.dispose();
    super.dispose();
  }

  void display(Barcode barcode) {
    Navigator.of(context).popAndPushNamed('display', arguments: barcode);
  }
}