Introduced ParseToDoule function into mUtil as suggested by @AroonPro. I have used NumberFormat to do the parse as recommended by the Oracle java documentation. Fixes #185

CHANGELOG.md

@@ -1,5 +1,6 @@
 	OpenSeizureDetector Android App - Change Log
 	============================================
+    V4.2.8 - Fixed crash in export data function when using european style comma based decimal separator.
     V4.2.7 - BLE2 data source re-start fixed??
     V4.2.6 - Fixed problem with notifications in Android 13
            - Improved start-up checks for permissions

app/src/main/AndroidManifest.xml

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
-    android:versionCode="140"
+    android:versionCode="142"
-    android:versionName="4.2.7">
+    android:versionName="4.2.8">
     <!-- android:allowBackup="false" -->
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
 

app/src/main/java/uk/org/openseizuredetector/ExportDataActivity.java

@@ -35,11 +35,13 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.text.DateFormat;
+import java.text.NumberFormat;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Date;
+import java.util.Locale;
 
 public class ExportDataActivity extends AppCompatActivity
         implements View.OnClickListener {
@@ -198,8 +200,8 @@ public class ExportDataActivity extends AppCompatActivity
         if (view == mExportBtn) {
             mDateTxt.setText(String.format("%02d-%02d-%04d", mDay, mMonth + 1, mYear));
             mTimeTxt.setText(String.format("%02d:%02d:%02d", mHour, mMinute, 00));
-            mDuration = Double.parseDouble(mDurationTxt.getText().toString());
 
+            mDuration = mUtil.parseToDouble(mDurationTxt.getText().toString());
             String dateTimeStr = String.format("%04d-%02d-%02dT%02d:%02d:%02dZ", mYear, mMonth + 1, mDay, mHour, mMinute, 00);
             //mUtil.showToast(dateTimeStr);
             mEndDate = mUtil.string2date(dateTimeStr);

app/src/main/java/uk/org/openseizuredetector/OsdUtil.java

@@ -59,6 +59,7 @@ import java.io.File;
 import java.io.FileWriter;
 import java.net.InetAddress;
 import java.net.NetworkInterface;
+import java.text.NumberFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
@@ -66,6 +67,7 @@ import java.util.Arrays;
 import java.util.Date;
 import java.util.Enumeration;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.function.Consumer;
 
 /**
@@ -778,4 +780,27 @@ public class OsdUtil {
         return allOk;
     }
 
+    public double parseToDouble(String userInput) {
+        /**
+         * Parse a string to a double value, taking localisation into account.
+         * Using NumberFormat as recommended by https://docs.oracle.com/javase%2F7%2Fdocs%2Fapi%2F%2F/java/lang/Double.html#valueOf(java.lang.String)
+         */
+        double retVal;
+        try {
+            Locale currentLocale;
+            if (android.os.Build.VERSION.SDK_INT < 24) {
+                currentLocale = mContext.getResources().getConfiguration().locale;
+            } else {
+                currentLocale = mContext.getResources().getConfiguration().getLocales().get(0);
+            }
+            NumberFormat nf = NumberFormat.getInstance(currentLocale);
+            retVal = nf.parse(userInput).doubleValue();
+        } catch (ParseException e) {
+            // Handle invalid input (e.g., non-numeric characters)
+            showToast("Invalid input. Please enter a valid numeric value.");
+            retVal = 0.0;
+        }
+        return(retVal);
+    }
+
 }

app/src/main/res/values/strings.xml

@@ -3,6 +3,7 @@
     <string name="app_name">OpenSeizureDetector</string>
     <string name="changelog">
         "\n
+        \nV4.2.8 - fixed crash in export data function.
         \nV4.2.7 - Finally fixed BLE2 data source re-start after dropping connection?
         \nV4.2.6 - Fixed issues with Android 13 notifications and BLE data source shutdown.  Added support for V2.x of Garmin watch app, Added new BLE2 data source, signal strength and battery level graphs.
         \nV4.2.4 - Fault alarm rather than crash if bluetooth system crashes.