I/flutter ( 8777): java.io.IOException: cannot create document: File not in PDF format or corrupted.

[franquicidad]

Hello im having some problems with the file i have this logic in screen 1 ...
Future goToPdfCreator(BuildContext context,
UserModelString userModelString) async {
final pdf = pw.Document();
Directory? docDirectory = await getExternalStorageDirectory();
if (docDirectory != null) {
var path = docDirectory.path;
var file = File('$path/laboralCertificate.pdf');
await file.writeAsBytes(await pdf.save());
Navigator.of(context).push(MaterialPageRoute(
builder: (context) =>
PdfCreator(
userModelString: userModelString, path: path,)));
}
}

class 2 PdfCreator.....

import 'dart:async';
import 'dart:io';

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_pdfview/flutter_pdfview.dart';
import 'package:lab_cert_globant/Model/user_dates_display.dart';
import 'package:path_provider/path_provider.dart';
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart' as pw;

class PdfCreator extends StatefulWidget {
PdfCreator(
{Key? key,
required this.userModelString,
required this.path
})
: super(key: key);
final String path;
final UserModelString userModelString;

@OverRide
State createState() => _PdfCreatorState();
}

class _PdfCreatorState extends State with WidgetsBindingObserver {
final pdf = pw.Document();
var file;
final Completer _controller =
Completer();
int? pages = 0;
int? currentPage = 0;
bool isReady = false;
String errorMessage = '';

writeOnPdf() {
pdf.addPage(
pw.Page(
pageFormat: PdfPageFormat.letter,
build: (pw.Context context) {
return pw.Column(
crossAxisAlignment: pw.CrossAxisAlignment.center,
children: [
pw.Column(
crossAxisAlignment: pw.CrossAxisAlignment.start,
children: [
pw.Text(widget.userModelString.companyName),
pw.Divider(height: 20),
pw.Text(widget.userModelString.companyNumber),
pw.Divider(height: 20),
pw.Text('Certificado'),
pw.Divider(height: 20),
pw.Column(
crossAxisAlignment: pw.CrossAxisAlignment.start,
children: [
pw.Text(
'Por medio de la presente certifico que el señor'
'${widget.userModelString.name},identificado con Cédula de Ciudadania No. ${widget.userModelString.userId}, trabaja actualmente en la empresa'
'${widget.userModelString.companyName} con NIT: ${widget.userModelString.companyNumber}, desde ${widget.userModelString.initialDate}, con un contrato a termino indefinido'
'y bajo el cargo de ${widget.userModelString.rol}. Con horario laboral de 9 horas diarias de lunes a viernes y un total de 45 horas'
'semanales. Percibiento un Sueldo Basico mensual de ${widget.userModelString.salary} ${widget.userModelString.currency}.'),
pw.Divider(height: 20),
pw.Text(
'Se expide el presente certificado a solicitud del interesado en la fecha ${widget.userModelString.endDate}'),
pw.Divider(height: 20),
pw.Text(
'Para confirmar esta certificación, comuniquese enviando el presente certificado al correo'
'electronico Pjourney-COLPE@globant.com para validacion.'),
pw.Divider(height: 20),
pw.Divider(height: 20),
pw.Text('Yullo'),
pw.Text('Pealyst'),
pw.Text('1'),
pw.Text('yul@glob.com'),
])
])
]);
},
),
);
}

Future savePdf() async {
Directory? docDirectory = await getExternalStorageDirectory();
if(docDirectory != null) {
var path = docDirectory.path;
file = File('$path/laboralCertificate.pdf');
await file.writeAsBytes(await pdf.save());
}
}

@OverRide
Widget build(BuildContext context) {
writeOnPdf();
return SafeArea(
child: Scaffold(
appBar: AppBar(title: Text('Save Pdf'),),
body: Stack(
children: [
PDFView(
filePath: widget.path,
enableSwipe: true,
swipeHorizontal: true,
autoSpacing: false,
pageFling: true,
pageSnap: true,
defaultPage: currentPage!,
fitPolicy: FitPolicy.BOTH,
preventLinkNavigation: true,
onRender: (_pages) {
setState(() {
pages = _pages;
isReady = true;
});
},
onError: (error) {
setState(() {
errorMessage = error.toString();
});
print(error.toString());
},
onPageError: (page, error) {
setState(() {
errorMessage = '$page: ${error.toString()}';
});
print('$page: ${error.toString()}');
},
onViewCreated: (PDFViewController pdfViewController) {
_controller.complete(pdfViewController);
},
onLinkHandler: (String? uri) {
print('goto uri: $uri');
},
onPageChanged: (int? page, int? total) {
print('page change: $page/$total');
setState(() {
currentPage = page;
});
},
),
errorMessage.isEmpty
? !isReady
? const Center(
child: CircularProgressIndicator(),
)
: Container()
: Center(
child: Text(errorMessage),
)
],
),
),
);
}
}

And i get the title of this issue printed on screen what seems to be wrong please help!.