Missing concrete implementation of StatelessWidget - flutter

Question

This page is my PhotoPreviewScreen where I send the photo that comes from the camera screen to the home page after clicking the button in the code below.
I am getting some interesting errors, that I have not seen before with very little in the docs, which are in the screenshot.
Has anyone seen these before? How can I rectify?
import 'package:flutter/material.dart';
import 'dart:io';
class PhotoPreviewScreen extends StatelessWidget {
Function setData;
PhotoPreviewScreen({Key key, this.setData}) : super(key: key);
}
class _PhotoPreviewScreenState extends State<PhotoPreviewScreen> {
final String imagePath;
var image;
Future _openGallery() async {}
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton: FloatingActionButton(
onPressed: () => Navigator.pop(
context), // Go back to the camera to take the picture again
child: Icon(Icons.camera_alt),
),
appBar: AppBar(title: Text('Photo Preview')),
body: Column(children: [
Expanded(child: Image.file(File(imagePath))),
const SizedBox(height: 16.0),
OutlineButton(
onPressed: () {
_openGallery();
Navigator.pop(context);
},
child: Text('Okay'),
borderSide: BorderSide(
color: Color(
0xff33333D)),
),
]),
);
}
}
errors

Answer 1

class PhotoPreviewScreen extends StatefulWidget {Function setData; PhotoPreviewScreen({Key key, this.setData}) : super(key: key); }
I guess it should be "StatefulWidget" instead of "StatelesWidget".

Answer 2

Try the below code snippets:
import 'package:flutter/material.dart';
import 'dart:io';
class PhotoPreviewScreen extends StatefulWidget {
Function setData;
PhotoPreviewScreen({Key key, this.setData}) : super(key: key);
_PhotoPreviewScreenState createState() => _PhotoPreviewScreenState();
}
class _PhotoPreviewScreenState extends State<PhotoPreviewScreen> {
final String imagePath = ' ';
var image;
Future _openGallery() async {}
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton: FloatingActionButton(
onPressed: () => Navigator.pop(
context), // Go back to the camera to take the picture again
child: Icon(Icons.camera_alt),
),
appBar: AppBar(title: Text('Photo Preview')),
body: Column(children: [
Expanded(child: Image.file(File(imagePath))),
const SizedBox(height: 16.0),
OutlineButton(
onPressed: () {
_openGallery();
Navigator.pop(context);
},
child: Text('Okay'),
borderSide: BorderSide(
color: Color(
0xff33333D)),
),
]),
);
}
}