Flutter open_file.dart not opening pdf file - flutter

Question

Im noob in flutter, i try to recreate this proses,create, save then launch pdf, this app has 2 dart file:
1. main.dart
import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_pdf/pdf.dart';
import 'mobile.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {...}
class MyHomePage extends StatefulWidget {...}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: ElevatedButton(
child: Text('Cliick Me'),
onPressed: _createPDF,
),
),
);
}
Future<void> _createPDF() async {
PdfDocument document = PdfDocument();
final page = document.pages.add();
page.graphics.drawString(
'welcome',
PdfStandardFont(PdfFontFamily.helvetica, 30)
);
List<int> bytes = document.save();
document.dispose();
//FileSaveHelper.saveAndLaunchFile(bytes, 'Outfile.pdf');
saveAndLaunchFile(bytes, 'Outfile.pdf');
}
2.mobile.dart
import 'dart:io' as io;
import 'dart:io';
import 'package:open_file/open_file.dart';
import 'package:path_provider/path_provider.dart';
Future<void> saveAndLaunchFile(List<int> bytes, String fileName) async {
try {
final path = (await getExternalStorageDirectory())!.path;
print('filepath : $path/$fileName');
String data='empty';
print('data pos1= $data');
data = (await io.File('$path/$fileName').exists()).toString();
final file = File('$path/$fileName');
await file.writeAsBytes(
bytes,
flush: true
);
print('data pos2= $data');
OpenFile.open('$path/$fileName');
print('done');
}
catch (e) {
print('error : $e');
}
}
Now when I press 'click me', it does nothing, it supposed to show 'welcome' String from main.dart
the output from mobile.dart are bellow:
Syncing files to device Android SDK built for x86...
Reloaded 1 of 955 libraries in 310ms.
I/flutter ( 3688): filepath : `/storage/emulated/0/Android/data/com.cg2.my_first_try/files/Outfile.pdf`
I/flutter ( 3688): data pos1= empty
I/flutter ( 3688): data pos2= true
I/flutter ( 3688): done
The funny things, the day before, when i first install android studio, flutter and run this program, it was working. Then I updated dependency on yaml file, then on this perticular line on mobile.dart, asking
final path = (await getExternalStorageDirectory()).path; generate error ....potentialy null.
so i change into :
final path = (await getExternalStorageDirectory())!.path;
lastly, iam using ubuntu 20.04, i just need to understand whats going on, is it androdi studio or emulator problem, or do linux need permision to getExternalStorageDirectory. Thanks.

Answer 1

Its seem ths java version that causing this. after googling, it turns out openJdk16 has campatible issues, messing up gradle creation. So i downgrade to 11, so far looks good.

Answer 2

To use jdk 16 you should upgrade to:
android/gradle/wrapper/gradle-wrapper.properties
distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip
android/build.gradle
classpath 'com.android.tools.build:gradle:7.0.1'
my jdk
java 16.0.1 2021-04-20
Java(TM) SE Runtime Environment (build 16.0.1+9-24)
Java HotSpot(TM) 64-Bit Server VM (build 16.0.1+9-24, mixed mode, sharing)