Navigate to new page once upload is done

Question

i'd like to naviagte to a new page to display the uploaded image , I've created custom function 'navigateToNewPage' to navigate , but I get this error

This expression has a type of 'void' so its value can't be used. Try checking to see if you're using the correct API; there might be a function or call that returns void you didn't expect. Also check type parameters and variables which might also be void.

code :

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: AppBar(
        title: Text("Pick Image Camera"),
        backgroundColor: Colors.green,
      ),
      body: Center(
        child: Container(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.spaceAround,
            children: [
              Card(
                child: (imageFile == null)
                    ? Text("Choose Image")
                    : navigateToNewPage() // here's the problem
,
              ),
              MaterialButton(
                textColor: Colors.white,
                color: Colors.pink,
                onPressed: () {
                  _showChoiceDialog(context);
                },
                child: Text("Select Image"),
              )
            ],
          ),
        ),
      ),
    );
  }

  void _openGallery(BuildContext context) async {
    final pickedFile = await ImagePicker().getImage(
      source: ImageSource.gallery,
    );
    setState(() {
      imageFile = pickedFile!;
    });

    Navigator.pop(context);
  }

  void _openCamera(BuildContext context) async {
    final pickedFile = await ImagePicker().getImage(
      source: ImageSource.camera,
    );
    setState(() {
      imageFile = pickedFile!;
    });
    Navigator.pop(context);
  }

  
  void navigateToNewPage() {
    Navigator.push(
      context,
      MaterialPageRoute(builder: (context) => second()),
    );
  }

Answer 1

The error message tells you the problem:

1. "Card()" is expecting a widget argument for "child".
2. Your method, "navigateToNewPage()", is a void function - it doesn't return anything.
3. Change "navigateToNewPage()" to return a widget; or - better - modify your code so that your app simply goes to a new page as soon as you've picked a file.

PS: Here's a tutorial - with some example code - that might help:

Flutter Image Picker : How to pick image from Gallery or Camera and Display it?