light_sensor_capture/lib/main.dart

import 'dart:convert';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:light_sensor_capture/light_sensor_event.dart';
import 'package:intl/intl.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Sensor Capture',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // TRY THIS: Try running your application with "flutter run". You'll see
        // the application has a purple toolbar. Then, without quitting the app,
        // try changing the seedColor in the colorScheme below to Colors.green
        // and then invoke "hot reload" (save your changes or press the "hot
        // reload" button in a Flutter-supported IDE, or press "r" if you used
        // the command line to start the app).
        //
        // Notice that the counter didn't reset back to zero; the application
        // state is not lost during the reload. To reset the state, use hot
        // restart instead.
        //
        // This works for code too, not just values: Most code changes can be
        // tested with just a hot reload.
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.greenAccent),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Sensor Capture'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int mState = 0;
  static const MethodChannel methodChannel =
      MethodChannel('tw.moonjuice.light_sensor.method');
  List mLightSensorEvents = [];

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // TRY THIS: Try changing the color here to a specific color (to
        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
        // change color while the other colors stay the same.
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          //
          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
          // action in the IDE, or press "p" in the console), to see the
          // wireframe for each widget.
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Spacer(),
            StreamBuilder<LightSensorEvent>(
                stream: streamSensorEventFromNative(),
                builder: (context, snapshot) {
                  if (snapshot.hasData) {
                    if (mState == 1) {
                      mLightSensorEvents.add(snapshot.data);
                    }
                    return Column(
                      children: [
                        Text(
                          'Sensor Data:',
                          style: Theme.of(context).textTheme.headlineLarge,
                        ),
                        Text(
                          snapshot.data!.lux.toString(),
                          style: Theme.of(context).textTheme.headlineLarge,
                        ),
                        Text(
                          snapshot.data!.timestamp.toString(),
                          style: Theme.of(context).textTheme.headlineLarge,
                        )
                      ],
                    );
                  } else {
                    return const CircularProgressIndicator();
                  }
                }),
            Spacer(),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Spacer(),
                ElevatedButton(
                  onPressed: (mState == 0) ? onPressed : null,
                  child: Text('Start Record'),
                ),
                Spacer(),
                ElevatedButton(
                    onPressed: (mState == 1) ? onPressed : null,
                    child: Text('Stop Record')),
                Spacer(),
              ],
            ),
            Spacer(),
          ],
        ),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

  Future<void> onPressed() async {
    setState(() {
      mState = ((mState == 0) ? 1 : 0);
    });
    if (mState == 0) {
      final String downloadsPath =
          await methodChannel.invokeMethod('getExternalDownloadsPath');
      DateTime now = DateTime.now();
      String formattedDate = DateFormat('yyyy-MM-dd_HH-mm-ss').format(now);
      File file = File('$downloadsPath/$formattedDate.txt');
      var sink = file.openWrite();
      sink.write(jsonEncode(mLightSensorEvents));
      await sink.flush();
      await sink.close();
      mLightSensorEvents.clear();
    }
  }

  Stream<LightSensorEvent> streamSensorEventFromNative() {
    const eventChannel = EventChannel('tw.moonjuice.light_sensor.stream');
    return eventChannel
        .receiveBroadcastStream()
        .map((event) => LightSensorEvent(event['lux'], event['timestamp']));
  }
}