I want to load other screen properly on my flutter app

Question

In my AppBar menu I tried to put a button with this function (for change the screen):

        onPressed: (){ 
            Navigator.push(
            context,
             MaterialPageRoute(builder: (context) => Read_Pdf()),
          );
        }

But always appears "... => Read_Pdf())," with error cause "2 positional argument(s) expected, but 0 found. Try adding the missing arguments."

This is the content of the file.dart which contains the Read_Pdf Class:

import 'dart:io';
import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:flutter_full_pdf_viewer/full_pdf_viewer_scaffold.dart';

const String _documentPath = 'PDFs/manual_demo.pdf';

// ignore: camel_case_types
class Read_Pdf extends StatelessWidget {

  final BuildContext context;
  String pdfPath;
  Read_Pdf(this.context, this.pdfPath);

  Future<String> prepareTestPdf() async {
    final ByteData bytes = await DefaultAssetBundle.of(context).load(_documentPath);
    final Uint8List list = bytes.buffer.asUint8List();

    final tempDir = await getTemporaryDirectory();
    final tempDocumentPath = '${tempDir.path}/$_documentPath';

    final file = await File(tempDocumentPath).create(recursive: true);
    file.writeAsBytesSync(list);

    return tempDocumentPath;
  }


  @override
  Widget build(BuildContext context) {
    return PDFViewerScaffold(
        appBar: AppBar(
          title: Text("Document"),
        ),
        path: pdfPath);
  }
}

I know that there is a conflict with the pdfPath variable, but I don´t know how to solve it.

Solution 1

It happens because you have not passed the arguments to the constructor of Read_Pdf()

Read_Pdf(this.context, this.pdfPath);

It needs context and the pdfPath, you can do it like this

onPressed: (){ 
        Navigator.push(
        context,
         MaterialPageRoute(builder: (context) => Read_Pdf(context, pdfPath)),
      );
    }

That it'll do it.

But in your implementation:

I can see you have a demo pdf in Read_Pdf

Change your constructor to

Read_Pdf({this.context, this.pdfPath = _documentPath});

What this.pdfPath = _documentPath does is it assigns _documentPath to pdfPath if it's not provided when Read_Pdf is instantiated.

So now the onPressed function will change to

onPressed: (){ 
        Navigator.push(
        context,
         MaterialPageRoute(builder: (context) => Read_Pdf(context: context)),
      );
    }

Solution 2

it needs context and pdf path() try the following code :

onpressesd(){
Navigator.push(context,MaterialPageRoute(builder :(context) => Read_pdf(context: context)))
}

Solution 3

If you don't need this variable to forward to class Read_pdf from other class, you must remove constructor: Read_Pdf(this.context, this.pdfPath); If you remove this one line, error disappears.

If You need this variables, you must run class with arguments:

MaterialPageRoute(builder: (context) => Read_Pdf(context: context, pdfPath: pdfPath)),

Comments

[Arsh Shaikh]

It would be amazing if you could just tick my answer as the selected answer. It also helps others know that the question is already answered so people can try answering the people who are yet to receive a solution.