I have two pages P1 and P2 .P1 has a button that navigates to P2. P2 has a function to list all pdf from the device. I want to show the circular progress bar with P1 button and want to navigate and remove the circular bar once all files get

CodePudding user response：

This is just Example That can help you.

// Test1 page

import 'package:demostack/test2page.dart';
import 'package:flutter/material.dart';

class Test1Page extends StatelessWidget {
  const Test1Page({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: TextButton(
            onPressed: () {

             // Navigat to Other Page

              Navigator.of(context).push(MaterialPageRoute(
                builder: (context) => const Test2Page(),
              ));
            },
            child: const Text('goto 2',style: TextStyle(fontSize: 30),)),
      ),
    );
  }
}

//Test2Page

import 'package:demostack/test3page.dart';
import 'package:flutter/material.dart';

class Test2Page extends StatefulWidget {
  const Test2Page({Key? key}) : super(key: key);

  @override
  _Test2PageState createState() => _Test2PageState();
}

    class _Test2PageState extends State<Test2Page> {
    //one bool var to know is processing or not
    //you can make this variable when your files are processing
    bool isProgress=false;
    
      @override
      void initState() {
    
        Future.delayed(Duration(seconds: 3),(){
         setState(() {
            //make this variable true when you get your files
           isProgress=true;
         });
        });
        super.initState();
      }
      @override
      Widget build(BuildContext context) {
        return Scaffold(
          body: Center(
    
            //set this condition where you are showing your files.
            child:isProgress==false?CircularProgressIndicator(color: Colors.red,): TextButton(
                onPressed: () => Navigator.of(context).push(MaterialPageRoute(
                  builder: (context) => const Test3Page(),
                )),
                child: const Text('goto 3',style: TextStyle(fontSize: 30))),
          ),
        );
      }
    }