improves the usability of the app

open_wearable/android/app/src/main/kotlin/com/example/open_wearable/MainActivity.kt

@@ -1,5 +1,36 @@
 package edu.kit.teco.openWearable
 
+import android.content.Intent
+import android.provider.Settings
 import io.flutter.embedding.android.FlutterActivity
+import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.plugin.common.MethodChannel
 
-class MainActivity: FlutterActivity()
+class MainActivity : FlutterActivity() {
+  companion object {
+    private const val SYSTEM_SETTINGS_CHANNEL = "edu.kit.teco.open_wearable/system_settings"
+  }
+
+  override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
+    super.configureFlutterEngine(flutterEngine)
+
+    MethodChannel(
+      flutterEngine.dartExecutor.binaryMessenger,
+      SYSTEM_SETTINGS_CHANNEL,
+    ).setMethodCallHandler { call, result ->
+      if (call.method == "openBluetoothSettings") {
+        try {
+          val intent = Intent(Settings.ACTION_BLUETOOTH_SETTINGS).apply {
+            addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+          }
+          startActivity(intent)
+          result.success(true)
+        } catch (_: Exception) {
+          result.success(false)
+        }
+      } else {
+        result.notImplemented()
+      }
+    }
+  }
+}

open_wearable/ios/Runner/AppDelegate.swift

@@ -8,9 +8,10 @@ import UIKit
     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
   ) -> Bool {    
     let controller: FlutterViewController = window?.rootViewController as! FlutterViewController
-    let channel = FlutterMethodChannel(name: "edu.teco.open_folder", binaryMessenger: controller.binaryMessenger)
+    let openFolderChannel = FlutterMethodChannel(name: "edu.teco.open_folder", binaryMessenger: controller.binaryMessenger)
+    let systemSettingsChannel = FlutterMethodChannel(name: "edu.kit.teco.open_wearable/system_settings", binaryMessenger: controller.binaryMessenger)
 
-    channel.setMethodCallHandler { (call: FlutterMethodCall, result: @escaping FlutterResult) in
+    openFolderChannel.setMethodCallHandler { (call: FlutterMethodCall, result: @escaping FlutterResult) in
       if call.method == "openFolder", let args = call.arguments as? [String: Any], let path = args["path"] as? String {
         guard let url = URL(string: path) else {
           result(FlutterError(code: "INVALID_ARGUMENT", message: "Invalid folder path", details: nil))
@@ -27,6 +28,25 @@ import UIKit
       }
     }
 
+    systemSettingsChannel.setMethodCallHandler { (call: FlutterMethodCall, result: @escaping FlutterResult) in
+      if call.method == "openBluetoothSettings" {
+        guard let settingsUrl = URL(string: UIApplication.openSettingsURLString) else {
+          result(false)
+          return
+        }
+
+        if UIApplication.shared.canOpenURL(settingsUrl) {
+          UIApplication.shared.open(settingsUrl, options: [:]) { success in
+            result(success)
+          }
+        } else {
+          result(false)
+        }
+      } else {
+        result(FlutterMethodNotImplemented)
+      }
+    }
+
     GeneratedPluginRegistrant.register(with: self)
     return super.application(application, didFinishLaunchingWithOptions: launchOptions)
   }

open_wearable/lib/apps/heart_tracker/widgets/rowling_chart.dart

@@ -1,12 +1,13 @@
 import 'dart:async';
 import 'dart:math';
 import 'package:flutter/material.dart';
-import 'package:community_charts_flutter/community_charts_flutter.dart' as charts;
+import 'package:community_charts_flutter/community_charts_flutter.dart'
+    as charts;
 
 class RollingChart extends StatefulWidget {
   final Stream<(int, double)> dataSteam;
   final int timestampExponent; // e.g., 6 for microseconds to milliseconds
-  final int timeWindow; // in milliseconds
+  final int timeWindow; // in seconds
 
   const RollingChart({
     super.key,
@@ -20,8 +21,9 @@ class RollingChart extends StatefulWidget {
 }
 
 class _RollingChartState extends State<RollingChart> {
-  List<charts.Series<_ChartPoint, int>> _seriesList = [];
-  final List<_ChartPoint> _data = [];
+  List<charts.Series<_ChartPoint, num>> _seriesList = [];
+  final List<_RawChartPoint> _rawData = [];
+  List<_ChartPoint> _normalizedData = [];
   StreamSubscription? _subscription;
 
   @override
@@ -42,56 +44,87 @@ class _RollingChartState extends State<RollingChart> {
   void _listenToStream() {
     _subscription = widget.dataSteam.listen((event) {
       final (timestamp, value) = event;
-    
+
       setState(() {
-        _data.add(_ChartPoint(timestamp, value));
-    
+        _rawData.add(_RawChartPoint(timestamp, value));
+
         // Remove old data outside time window
-        int cutoffTime = timestamp - (widget.timeWindow * pow(10, -widget.timestampExponent) as int);
-        _data.removeWhere((data) => data.time < cutoffTime);
-
+        final ticksPerSecond = pow(10, -widget.timestampExponent).toDouble();
+        final cutoffTime =
+            timestamp - (widget.timeWindow * ticksPerSecond).round();
+        _rawData.removeWhere((data) => data.timestamp < cutoffTime);
+
         _updateSeries();
       });
     });
   }
 
   void _updateSeries() {
+    if (_rawData.isEmpty) {
+      _normalizedData = [];
+      _seriesList = [];
+      return;
+    }
+
+    final firstTimestamp = _rawData.first.timestamp;
+    final secondsPerTick = pow(10, widget.timestampExponent).toDouble();
+
+    _normalizedData = _rawData
+        .map(
+          (point) => _ChartPoint(
+            (point.timestamp - firstTimestamp) * secondsPerTick,
+            point.value,
+          ),
+        )
+        .toList(growable: false);
+
     _seriesList = [
-        charts.Series<_ChartPoint, int>(
-          id: 'Live Data',
-          colorFn: (_, __) => charts.MaterialPalette.red.shadeDefault,
-          domainFn: (_ChartPoint point, _) => point.time,
-          measureFn: (_ChartPoint point, _) => point.value,
-          data: List.of(_data),
+      charts.Series<_ChartPoint, num>(
+        id: 'Live Data',
+        colorFn: (_, __) => charts.MaterialPalette.red.shadeDefault,
+        domainFn: (_ChartPoint point, _) => point.timeSeconds,
+        measureFn: (_ChartPoint point, _) => point.value,
+        data: _normalizedData,
       ),
     ];
   }
 
   @override
   Widget build(BuildContext context) {
-    final filteredPoints = _data;
+    final filteredPoints = _normalizedData;
 
-    final xValues = filteredPoints.map((e) => e.time).toList();
+    final xValues = filteredPoints.map((e) => e.timeSeconds).toList();
     final yValues = filteredPoints.map((e) => e.value).toList();
 
-    final int? xMin = xValues.isNotEmpty ? xValues.reduce((a, b) => a < b ? a : b) : null;
-    final int? xMax = xValues.isNotEmpty ? xValues.reduce((a, b) => a > b ? a : b) : null;
+    final double xMin = 0;
+    final double xMax = max(
+      widget.timeWindow.toDouble(),
+      xValues.isNotEmpty ? xValues.reduce((a, b) => a > b ? a : b) : 0,
+    );
 
-    final double? yMin = yValues.isNotEmpty ? yValues.reduce((a, b) => a < b ? a : b) : null;
-    final double? yMax = yValues.isNotEmpty ? yValues.reduce((a, b) => a > b ? a : b) : null;
+    final double? yMin =
+        yValues.isNotEmpty ? yValues.reduce((a, b) => a < b ? a : b) : null;
+    final double? yMax =
+        yValues.isNotEmpty ? yValues.reduce((a, b) => a > b ? a : b) : null;
 
     return charts.LineChart(
       _seriesList,
       animate: false,
       domainAxis: charts.NumericAxisSpec(
-        viewport: xMin != null && xMax != null
-          ? charts.NumericExtents(xMin, xMax)
-          : null,
+        viewport: charts.NumericExtents(xMin, xMax),
+        tickFormatterSpec: charts.BasicNumericTickFormatterSpec((num? value) {
+          if (value == null) return '';
+          final rounded = value.roundToDouble();
+          if ((value - rounded).abs() < 0.05) {
+            return '${rounded.toInt()}s';
+          }
+          return '${value.toStringAsFixed(1)}s';
+        }),
       ),
       primaryMeasureAxis: charts.NumericAxisSpec(
         viewport: yMin != null && yMax != null
-          ? charts.NumericExtents(yMin, yMax)
-          : null,
+            ? charts.NumericExtents(yMin, yMax)
+            : null,
       ),
     );
   }
@@ -103,9 +136,16 @@ class _RollingChartState extends State<RollingChart> {
   }
 }
 
+class _RawChartPoint {
+  final int timestamp;
+  final double value;
+
+  _RawChartPoint(this.timestamp, this.value);
+}
+
 class _ChartPoint {
-  final int time;
+  final double timeSeconds;
   final double value;
 
-  _ChartPoint(this.time, this.value);
+  _ChartPoint(this.timeSeconds, this.value);
 }