save sensor data as json file

android/app/build.gradle

@@ -8,15 +8,14 @@ plugins {
 android {
     namespace = "tw.moonjuice.light_sesnor_capture"
     compileSdk = flutter.compileSdkVersion
-    ndkVersion = flutter.ndkVersion
+    ndkVersion "25.1.8937393"
 
     compileOptions {
-        sourceCompatibility = JavaVersion.VERSION_1_8
+        sourceCompatibility JavaVersion.VERSION_17
-        targetCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_17
     }
-
     kotlinOptions {
-        jvmTarget = JavaVersion.VERSION_1_8
+        jvmTarget = 17
     }
 
     defaultConfig {

android/app/src/main/AndroidManifest.xml

@@ -1,4 +1,5 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <uses-permission android:name="android.permission.INTERNET"/>
     <application
         android:label="light_sesnor_capture"
         android:name="${applicationName}"

android/app/src/main/java/tw/moonjuice/light_sesnor_capture/MainActivity.java

@@ -1,20 +1,29 @@
 package tw.moonjuice.light_sesnor_capture;
 
+import android.Manifest;
 import android.content.Context;
+import android.content.pm.PackageManager;
 import android.hardware.Sensor;
 import android.hardware.SensorEvent;
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
 import android.os.Bundle;
+import android.os.Environment;
+import android.widget.Toast;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
+import java.util.HashMap;
+import java.util.Map;
+
 import io.flutter.embedding.android.FlutterActivity;
 import io.flutter.embedding.engine.FlutterEngine;
 import io.flutter.plugin.common.EventChannel;
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
 
-public class MainActivity extends FlutterActivity implements EventChannel.StreamHandler, SensorEventListener {
+public class MainActivity extends FlutterActivity implements EventChannel.StreamHandler, SensorEventListener, MethodChannel.MethodCallHandler {
     private Sensor mLightSensor;
     private SensorManager mSensorManager;
     private EventChannel.EventSink mEventSink;
@@ -30,24 +39,39 @@ public class MainActivity extends FlutterActivity implements EventChannel.Stream
         super.configureFlutterEngine(flutterEngine);
         EventChannel eventChannel = new EventChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), "tw.moonjuice.light_sensor.stream");
         eventChannel.setStreamHandler(this);
+        MethodChannel methodChannel = new MethodChannel(flutterEngine.getDartExecutor(), "tw.moonjuice.light_sensor.method");
+        methodChannel.setMethodCallHandler(this);
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        mSensorManager.registerListener(this, mLightSensor, SensorManager.SENSOR_DELAY_FASTEST);
+    }
+
+    @Override
+    protected void onStop() {
+        mSensorManager.unregisterListener(this);
+        super.onStop();
     }
 
     @Override
     public void onListen(Object arguments, EventChannel.EventSink events) {
         mEventSink = events;
-        mSensorManager.registerListener(this, mLightSensor, SensorManager.SENSOR_DELAY_FASTEST);
     }
 
     @Override
     public void onCancel(Object arguments) {
         mEventSink = null;
-        mSensorManager.unregisterListener(this);
     }
 
     @Override
     public void onSensorChanged(SensorEvent sensorEvent) {
         if (mEventSink != null) {
-            mEventSink.success(sensorEvent.values[0]);
+            final Map data = new HashMap();
+            data.put("lux", sensorEvent.values[0]);
+            data.put("timestamp", sensorEvent.timestamp);
+            mEventSink.success(data);
         }
     }
 
@@ -55,4 +79,22 @@ public class MainActivity extends FlutterActivity implements EventChannel.Stream
     public void onAccuracyChanged(Sensor sensor, int i) {
 
     }
+
+    @Override
+    public void onMethodCall(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
+        switch (call.method) {
+            case "getExternalDownloadsPath":
+                result.success(Environment.getExternalStoragePublicDirectory(
+                        Environment.DIRECTORY_DOWNLOADS).getAbsolutePath());
+                break;
+            case "start":
+                Toast.makeText(getContext(), "start", Toast.LENGTH_SHORT).show();
+                result.success("success");
+                break;
+            default:
+                Toast.makeText(getContext(), "stop", Toast.LENGTH_SHORT).show();
+                result.success("success");
+                break;
+        }
+    }
 }

android/gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.10.2-all.zip

android/settings.gradle

@@ -18,8 +18,8 @@ pluginManagement {
 
 plugins {
     id "dev.flutter.flutter-plugin-loader" version "1.0.0"
-    id "com.android.application" version "8.1.0" apply false
+    id "com.android.application" version "8.3.2" apply false
-    id "org.jetbrains.kotlin.android" version "1.8.22" apply false
+    id "org.jetbrains.kotlin.android" version "2.0.20" apply false
 }
 
 include ":app"

lib/light_sensor_event.dart

@@ -0,0 +1,11 @@
+import 'dart:ffi';
+
+class LightSensorEvent {
+  final double lux;
+  final int timestamp;
+  LightSensorEvent(this.lux, this.timestamp);
+  Map<String, dynamic> toJson() => {
+        'lux': lux,
+        'timestamp': timestamp,
+      };
+}

lib/main.dart

@@ -1,5 +1,10 @@
+import 'dart:convert';
+import 'dart:io';
+
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:light_sesnor_capture/light_sensor_event.dart';
+import 'package:intl/intl.dart';
 
 void main() {
   runApp(const MyApp());
@@ -56,18 +61,10 @@ class MyHomePage extends StatefulWidget {
 }
 
 class _MyHomePageState extends State<MyHomePage> {
-  int _counter = 0;
+  int mState = 0;
-
+  static const MethodChannel methodChannel =
-  void _incrementCounter() {
+      MethodChannel('tw.moonjuice.light_sensor.method');
-    setState(() {
+  List mLightSensorEvents = [];
-      // This call to setState tells the Flutter framework that something has
-      // changed in this State, which causes it to rerun the build method below
-      // so that the display can reflect the updated values. If we changed
-      // _counter without calling setState(), then the build method would not be
-      // called again, and so nothing would appear to happen.
-      _counter++;
-    });
-  }
 
   @override
   Widget build(BuildContext context) {
@@ -107,12 +104,15 @@ class _MyHomePageState extends State<MyHomePage> {
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
             Spacer(),
-            StreamBuilder<String>(
+            StreamBuilder<LightSensorEvent>(
                 stream: streamSensorEventFromNative(),
                 builder: (context, snapshot) {
                   if (snapshot.hasData) {
+                    if (mState == 1) {
+                      mLightSensorEvents.add(snapshot.data);
+                    }
                     return Text(
-                      'Sensor Data: ${snapshot.data}',
+                      'Sensor Data: ${jsonEncode(snapshot.data)}',
                       style: Theme.of(context).textTheme.headlineLarge,
                     );
                   } else {
@@ -125,10 +125,13 @@ class _MyHomePageState extends State<MyHomePage> {
               children: [
                 Spacer(),
                 ElevatedButton(
-                    onPressed: onPressed, child: Text('Start Record')),
+                  onPressed: (mState == 0) ? onPressed : null,
+                  child: Text('Start Record'),
+                ),
                 Spacer(),
                 ElevatedButton(
-                    onPressed: onPressed, child: Text('Stop Record')),
+                    onPressed: (mState == 1) ? onPressed : null,
+                    child: Text('Stop Record')),
                 Spacer(),
               ],
             ),
@@ -139,12 +142,28 @@ class _MyHomePageState extends State<MyHomePage> {
     );
   }
 
-  void onPressed() {}
+  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<String> streamSensorEventFromNative() {
+  Stream<LightSensorEvent> streamSensorEventFromNative() {
     const eventChannel = EventChannel('tw.moonjuice.light_sensor.stream');
     return eventChannel
         .receiveBroadcastStream()
-        .map((event) => event.toString());
+        .map((event) => LightSensorEvent(event['lux'], event['timestamp']));
   }
 }

pubspec.lock

@@ -75,6 +75,30 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  http:
+    dependency: transitive
+    description:
+      name: http
+      sha256: b9c29a161230ee03d3ccf545097fccd9b87a5264228c5d348202e0f0c28f9010
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.2"
+  http_parser:
+    dependency: transitive
+    description:
+      name: http_parser
+      sha256: "2aa08ce0341cc9b354a498388e30986515406668dbcc4f7c950c3e715496693b"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.0.2"
+  intl:
+    dependency: "direct main"
+    description:
+      name: intl
+      sha256: "00f33b908655e606b86d2ade4710a231b802eec6f11e87e4ea3783fd72077a50"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.20.1"
   leak_tracker:
     dependency: transitive
     description:
@@ -192,6 +216,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.7.2"
+  typed_data:
+    dependency: transitive
+    description:
+      name: typed_data
+      sha256: f9049c039ebfeb4cf7a7104a675823cd72dba8297f264b6637062516699fa006
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.0"
   vector_math:
     dependency: transitive
     description:
@@ -208,6 +240,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "14.2.5"
+  web:
+    dependency: transitive
+    description:
+      name: web
+      sha256: cd3543bd5798f6ad290ea73d210f423502e71900302dde696f8bff84bf89a1cb
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.0"
 sdks:
   dart: ">=3.5.4 <4.0.0"
   flutter: ">=3.18.0-18.0.pre.54"

pubspec.yaml

@@ -35,6 +35,7 @@ dependencies:
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^1.0.8
+  intl: ^0.20.1
 
 dev_dependencies:
   flutter_test: