Call a function in a screen from another screen in flutter

GingerAle
August 31, 2023
282 views
0 votes
2 Answers

i have a method _func() in HomeScreen.
i have a button in HomeScreen that navigate the user to ViewScreen from HomeScreen like this

Navigator.push(
      context,
      CupertinoModalPopupRoute(
        builder: (context) => ViewScreen(
          listItem: item,
          icon: icon,
        ),
      ),
    );

from that ViewScreen there is another button that navigates to AddEditScreen from ViewScreen like this

Navigator.of(context).pushReplacement(
      CupertinoPageRoute(
        builder: (context) => AddEditScreen(
          item: item,
        ),
      ),
    );

when i pop back from AddEditScreen i will be navigate back to HomeScreen.
and when that happens i want the _func() method in HomeScreen to run.
how can i do that?

Tags: dart flutter

Answers

In your homescreen do this:

class HomeScreen extends StatelessWidget {
  void _func() {
    // Whatever the code you have
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // Your user interface code must come here

      
      ElevatedButton(
        onPressed: () {
          Navigator.push(
            context,
            CupertinoModalPopupRoute(
              builder: (context) => ViewScreen(
                listItem: item,
                icon: icon,
                callback: _func, // to Pass the callback
              ),
            ),
          );
        },
        child: Text("Navigate to ViewScreen"),
      ),
    );
  }
}

In you Viewscreen do this:

class ViewScreen extends StatelessWidget {
  final Function callback; 

  ViewScreen({required this.callback, /* other properties you want to add*/});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // other codes

      // Button to navigate to AddEditScreen
      ElevatedButton(
        onPressed: () {
          Navigator.of(context).pushReplacement(
            CupertinoPageRoute(
              builder: (context) => AddEditScreen(
                item: item,
                callback: callback, // Pass the callback
              ),
            ),
          );
        },
        child: Text("Navigate to AddEditScreen"),
      ),
    );
  }
}

In your AddEditScreen do this:

class AddEditScreen extends StatelessWidget {
  final Function callback;

  AddEditScreen({required this.callback, /* other properties you want to add */});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      //code that's already present

      
      ElevatedButton(
        onPressed: () {
          // Call the callback before popping
          callback();

          // Pop back to the original HomeScreen
          Navigator.pop(context);
        },
        child: Text("Pop to HomeScreen"),
      ),
    );
  }
}

Check out this sample example :

import 'package:flutter/material.dart';

import 'package:flutter/cupertino.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(
        scaffoldBackgroundColor: darkBlue,
      ),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: HomeScreen(),
        ),
      ),
    );
  }
}

class HomeScreen extends StatelessWidget {
  void addFunction() {
    print(2 + 2);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(children: [
        ElevatedButton(
            onPressed: () async {
              Navigator.push(
                context,
                CupertinoModalPopupRoute(
                  builder: (context) => ViewScreen(() {
                    addFunction();
                  }),
                ),
              );
            },
            child: const Text('Go to View screen'))
      ]),
    );
  }
}

class ViewScreen extends StatelessWidget {
  Function onbackCallback;

  ViewScreen(this.onbackCallback);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(children: [
        ElevatedButton(
            onPressed: () async {
              final response = await Navigator.of(context).pushReplacement(
                CupertinoPageRoute(
                  builder: (context) => AddEditScreen(),
                ),
              );
              if (response) {
                onbackCallback.call();
              }
              print(response);
            },
            child: const Text('Go to addedit screen'))
      ]),
    );
  }
}

class AddEditScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(children: [
        ElevatedButton(
            onPressed: () {
              Navigator.of(context).pop(true);
            },
            child: const Text('Go back to home screen '))
      ]),
    );
  }
}

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