ImagePicker

import 'dart:io';
import 'package:image_picker/image_picker.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  File _image;
  final picker = ImagePicker();

  Future getImg() async {
    final pickedfile = await picker.getImage(source: ImageSource.camera);
    final File file = File(pickedfile.path);
    setState(() {
      if (pickedfile != null) {
        _image = file;
      } else {
        print('no image');
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Center(
        child: (_image == null) ? Text('no image') : Image.file(_image),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => getImg(),
        tooltip: 'pick image',
        child: Icon(Icons.add_a_photo),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}