Develop Reference

Voice Commands On Flutter Application

I tried to do give a command to the flutter application using voice commands and in the application there was a text to voice function. so when i tried to give read command using voice there was a repeat on that function. how to avoid the repeat.
I have tried to terminate the Listening function after getting one input but it dosen't work.
Tried to terminate the Listening function.
but same error
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:newsapp/screens/News_Screen.dart';
import 'package:newsapp/utils/app_colors.dart';
import 'package:newsapp/utils/assets_constants.dart';
import 'package:webfeed/webfeed.dart';
import 'package:flutter_tts/flutter_tts.dart';
import 'package:url_launcher/url_launcher.dart';
import 'dart:io';
import 'package:flutter/foundation.dart';
import 'package:flutter_speech/flutter_speech.dart';
const languages = const [
// const Language('Francais', 'fr_FR'),
const Language('English', 'en_US'),
const Language('Pусский', 'ru_RU'),
const Language('Italiano', 'it_IT'),
const Language('Español', 'es_ES'),
];
class Language {
final String name;
final String code;
const Language(this.name, this.code);
}
class BBCNews extends StatefulWidget {
#override
_BBCNewsState createState() => _BBCNewsState();
}
class _BBCNewsState extends State<BBCNews> {
late SpeechRecognition _speech;
FlutterTts flutterTts = FlutterTts();
bool _speechRecognitionAvailable = false;
bool _isListening = false;
String transcription = '';
String _currentLocale = 'en_US';
//Language selectedLang = languages.first;
#override
initState() {
super.initState();
activateSpeechRecognizer();
}
void activateSpeechRecognizer() {
//print('_MyAppState.activateSpeechRecognizer... ');
_speech = SpeechRecognition();
_speech.setAvailabilityHandler(onSpeechAvailability);
_speech.setRecognitionStartedHandler(onRecognitionStarted);
_speech.setRecognitionResultHandler(onRecognitionResult);
_speech.setRecognitionCompleteHandler(onRecognitionComplete);
_speech.setErrorHandler(errorHandler);
_speech.activate('en_US').then((res) {
setState(() => _speechRecognitionAvailable = res);
});
}
var client = http.Client();
Future myDevBlog() async {
var response = await client
.get(Uri.parse('http://feeds.bbci.co.uk/news/world/rss.xml'));
var channel = RssFeed.parse(response.body);
final item = channel.items;
return item;
}
Future<void> openFeed(String url) async {
if (await canLaunch(url)) {
await launch(
url,
forceSafariVC: true,
forceWebView: false,
);
return;
}
}
rightIcon() {
return const Icon(
Icons.keyboard_arrow_right,
color: Colors.grey,
size: 30,
);
}
#override
Widget build(BuildContext context) {
var currentIndex;
return Scaffold(
appBar: AppBar(
backgroundColor: AppColors.primaryColor,
//title: const Text('VoiceNews'),
title: Image.asset(
AssetConstants.iconPath,
width: 150,
),
elevation: 10.0,
actions: [
IconButton(
onPressed: _speechRecognitionAvailable && !_isListening
? () => start()
: null,
icon: const Icon(Icons.play_arrow_rounded)),
IconButton(
onPressed: _isListening ? () => stop() : null,
icon: const Icon(Icons.stop_circle))
],
),
body: StreamBuilder(
stream: myDevBlog().asStream(),
builder: (context, snapshot) {
if (snapshot.hasData) {
return ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (context, int index) {
if (transcription.toLowerCase() == "play") {
// _isListening = false;
//stop();
print(transcription);
speak(snapshot.data[1].title);
var currentIndex = 0;
} else if (transcription.toLowerCase() == "next") {
// _isListening = false;
speak(snapshot.data[2].title);
print(transcription);
} else if (transcription.toLowerCase() == "all") {
// _isListening = false;
errorHandler();
//speak("Wrong Input");
//cancel();
}
return Padding(
padding: const EdgeInsets.all(8.0),
child: Card(
child: ListTile(
title: Text(snapshot.data[index].title),
subtitle:
Text(snapshot.data[index].description),
//onTap: () =>
speak(snapshot.data[index].title),
// onTap: () =>
openFeed(snapshot.data[index].link),
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) =>
newsScreen(snapshot.data[index].link),
// Pass the arguments as part of the
RouteSettings. The
// DetailScreen reads the arguments
from these settings.
// settings: RouteSettings(
// arguments: todos[index],
// ),
),
);
print(snapshot.data[index].link);
},
onLongPress: () =>
speak(snapshot.data[index].description),
leading: Text((1 + index).toString()),
trailing: rightIcon(),
),
),
);
},
);
} else if (snapshot.hasError ||
snapshot.connectionState == ConnectionState.none) {
return Center(
child: Text(snapshot.error.toString()),
);
}
return const Center(
child: CircularProgressIndicator(),
);
},
),
);
}
// List<CheckedPopupMenuItem<Language>> get
_buildLanguagesWidgets => languages
void start() => _speech.activate(_currentLocale).then((_) {
return _speech.listen().then((result) {
print('_MyAppState.start => result $result');
setState(() {
_isListening = result;
});
});
});
void cancel() =>
_speech.cancel().then((_) => setState(() => _isListening =
false));
void stop() => _speech.stop().then((_) {
setState(() => _isListening = false);
});
void onSpeechAvailability(bool result) =>
setState(() => _speechRecognitionAvailable = result);
// void onCurrentLocale(String locale) {
// // print('_MyAppState.onCurrentLocale... $locale');
// setState(
// () => _currentLocale = languages.firstWhere((l) =>
l.code == locale));
// }
void onRecognitionStarted() {
setState(() => _isListening = true);
}
void onRecognitionResult(String text) {
// print('_MyAppState.onRecognitionResult... $text');
setState(() => transcription = text);
}
void onRecognitionComplete(String text) {
//print('_MyAppState.onRecognitionComplete... $text');
setState(() => _isListening = false);
}
void errorHandler() => activateSpeechRecognizer();
void speak(String text) async {
await flutterTts.speak(text);
await flutterTts.setLanguage("en-US");
await flutterTts.setPitch(1);
await flutterTts.setSpeechRate(0.6);
}
}

How to Retrieve Image/ Screenshot from Application Document Directory Flutter?

I'm trying to build an in app gallery function where I can screenshot certain widgets in the app and then display it inside the app's internal gallery screen. Currently, I am using the Flutter screenshot package and then I save the screenshot to the Application document directory path. But how do I retrieve the images back and display them later on the app again?

Here's how I've done it before using the path_provider package.
(this is only for one image, but you can adapt the code to retrieve multiple images).
Create an uninitialized variable:
Image? image;
then, in the initState:
void initState() {
_loadImage();
super.initState();
}
Here is the _loadImage()
Future<void> _loadImage() async {
final path = await imagePath;
final _doesTheImageExist = File('${path}/qr.png').existsSync();
print(_doesTheImageExist);
if (_doesTheImageExist == true) {
setState(() {
image = Image.file(File("${path}/qr.png"));
});
} else {
print('no');
setState(() {
image = null;
});
}
}
Create a getter to get the image path imagePath:
Future<String> get imagePath async {
final directory = (await getApplicationDocumentsDirectory()).path;
return '$directory/qr.png';
}
then, create a function to save the image to the device:
Future<void> _captureAndSaveQRCode() async {
final imageDirectory = await imagePath;
await _screenshotController.captureAndSave(imageDirectory,
fileName: 'qr.png');
await _loadImage();
// setState(() {});
}
Here is the complete runnable example:
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:qr_flutter/qr_flutter.dart';
import 'package:screenshot/screenshot.dart';
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const Scaffold(
body: QrCode(),
),
);
}
}
class QrCode extends StatefulWidget {
const QrCode({Key? key}) : super(key: key);
#override
State<QrCode> createState() => _QrCodeState();
}
class _QrCodeState extends State<QrCode> {
final _screenshotController = ScreenshotController();
Image? image;
#override
Widget build(BuildContext context) {
return Scaffold(
body: image != null
? Center(
child: Padding(
padding: const EdgeInsets.only(
top: 100.0,
),
child: Column(
children: [
image!,
],
),
))
: Center(
child: Column(
children: [
TextButton(
onPressed: _captureAndSaveQRCode,
child: Text("Save QrCode")),
Screenshot(
controller: _screenshotController,
child: _buildQRImage('data'))
],
),
),
);
}
Widget _buildQRImage(String data) {
return QrImage(
data: data,
size: 250.0,
version: QrVersions.auto,
errorCorrectionLevel: QrErrorCorrectLevel.H,
gapless: false,
foregroundColor: Colors.black,
backgroundColor: Colors.white,
);
}
Future<String> get imagePath async {
final directory = (await getApplicationDocumentsDirectory()).path;
return '$directory/qr.png';
}
Future<void> _loadImage() async {
final path = await imagePath;
final _doesTheImageExist = File('${path}/qr.png').existsSync();
print(_doesTheImageExist);
if (_doesTheImageExist == true) {
setState(() {
image = Image.file(File("${path}/qr.png"));
});
} else {
setState(() {
image = null;
});
}
}
Future<void> _captureAndSaveQRCode() async {
final imageDirectory = await imagePath;
await _screenshotController.captureAndSave(imageDirectory,
fileName: 'qr.png');
await _loadImage();
}
#override
void initState() {
_loadImage();
super.initState();
}
}

catch answer of WorkManager

I want to update the background color of my app in terms of result of my background task.
I use flutter_bloc and WorkManager.
I want my app to be blue during the action, and green if the result is good and red if my function throw an exception.
Or can I update my screen color in terms of result of my repo.getBattery call ?
Here in logs I can read workmanager.result error (bad url) but I can't catch it.
main.dart:
import 'package:batt/test_cubit.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:shared_preferences/shared_preferences.dart';
void main() {
WidgetsFlutterBinding.ensureInitialized();
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return BlocProvider(
create: (context) => TestCubit(),
child: MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
));
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key}) : super(key: key);
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
bool _sw_value = false;
TextEditingController _controller = TextEditingController(text: "url");
Future<Null> tmp() async{
SharedPreferences prefs = await SharedPreferences.getInstance();
setState(() {
_controller = TextEditingController(text: prefs.getString("url"));
});
}
#override
void initState(){
super.initState();
tmp();
}
#override
Widget build(BuildContext context) {
return BlocBuilder<TestCubit, TestState>(builder: (context, state) {
return Scaffold(
backgroundColor: state.status,
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
TextField(
controller: _controller,
maxLines: null,
keyboardType: TextInputType.url,
onChanged: (url) =>
context.read<TestCubit>().urlChanged(url),
),
const SizedBox(
height: 50,
),
CupertinoSwitch(
value: _sw_value,
onChanged: (value){
setState(() {
_sw_value = value;
});
if (value == true){
BlocProvider.of<TestCubit>(context).validate();
}
else {
BlocProvider.of<TestCubit>(context).cancel();
}
}
),
],
),
),
);
});
}
}
and my test_cubit.dart:
import 'dart:async';
import 'package:battery_plus/battery_plus.dart';
import 'package:bloc/bloc.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:workmanager/workmanager.dart';
import 'data/Repository/battery_repo.dart';
import 'data/data_provider/battery_provider.dart';
import 'package:http/http.dart' as http;
part 'test_state.dart';
const fetchBackground = "fetchBackground";
void callbackDispatcher() {
Workmanager().executeTask((task, inputData) async {
switch (task) {
case fetchBackground:
var battery = Battery();
var batlevel = await battery.batteryLevel;
final urlFinal = inputData!["string"] + batlevel.toString();
try {
await repo.getBattery(urlFinal);
} catch (e) {
return Future.error("bad url");
}
break;
}
return Future.value(true);
});
}
final BatteryRepository repo = BatteryRepository(api: ServerAPI(http.Client()));
class TestCubit extends Cubit<TestState> {
TestCubit() : super(TestState("", Colors.grey));
urlChanged(String url) {
state.path = url;
}
validate() async {
if (state.path != "") {
final SharedPreferences _prefs = await SharedPreferences.getInstance();
_prefs.setString('url', state.path);
}
WidgetsFlutterBinding.ensureInitialized();
await Workmanager().cancelAll();
await Workmanager().initialize(
callbackDispatcher,
isInDebugMode: false,
);
state.status = Colors.blue;
emit(state);
try {
Workmanager().registerPeriodicTask("1", fetchBackground,
backoffPolicy: BackoffPolicy.exponential,
inputData: {
'string': state.path,
});
} catch (e) {
state.status = Colors.red;
emit(state);
}
Workmanager().registerPeriodicTask("2", fetchBackground,
initialDelay: const Duration(minutes: 5),
inputData: {
'string': state.path,
});
Workmanager().registerPeriodicTask("3", fetchBackground,
initialDelay: const Duration(minutes: 10),
inputData: {
'string': state.path,
});
state.status = Colors.green;
emit(state);
}
cancel() async {
await Workmanager().cancelAll();
state.status = Colors.pink;
emit(state);
}
}
please can you help me ? :)
I'm very beginner so I think my code is not good at all too :/

Reading an image file from device storage and converting to Base64 results in an invalid base64 in Flutter

I'm trying to read file from a known path get base64 string from the image. I still don't understand why base64 is broken. This happens only in flutter code.
I did try doing the same conversion using a simple dart program i got the desired base64 string. This issue is happening in flutter.
onPressed: () async {
File imageFile =
await ImagePicker.pickImage(source: ImageSource.camera);
if (imageFile != null) {
Uint8List bytes = await imageFile.readAsBytes();
String base64data = base64.encode(bytes);
print(base64data);
}
}
Following is my console output.
W/ExifInterface(15331): Skip the tag entry since tag number is not defined: 2
W/ExifInterface(15331): Stop reading file since a wrong offset may cause an infinite loop: 0
I/chatty (15331): uid=10271(com.crowdanalytix.datax_app) Binder:15331_5 identical 2 lines
W/ExifInterface(15331): Stop reading file since a wrong offset may cause an infinite loop: 0
I/flutter (15331): 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
Base64 string which i'm getting is invalid. Can someone try this?
I'm using a OnePlus3t (ONEPLUS A3003).

print function did not print everything.
you can see full result with debug mode
code snippet
List<int> imageBytes = await _imageFile.readAsBytes();
String base64Image = base64Encode(imageBytes);
print(base64Image);
Copy base64 string from debug mode and paste to online converter, you can see result is correct.
full code from offical demo and add base64 convert
// Copyright 2019 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import 'dart:io';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:video_player/video_player.dart';
import 'dart:typed_data';
import 'package:image/image.dart' as ImageProcess;
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Image Picker Demo',
home: MyHomePage(title: 'Image Picker Example'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
File _imageFile;
dynamic _pickImageError;
bool isVideo = false;
VideoPlayerController _controller;
String _retrieveDataError;
Future<void> _playVideo(File file) async {
if (file != null && mounted) {
await _disposeVideoController();
_controller = VideoPlayerController.file(file);
await _controller.setVolume(1.0);
await _controller.initialize();
await _controller.setLooping(true);
await _controller.play();
setState(() {});
}
}
void _onImageButtonPressed(ImageSource source) async {
if (_controller != null) {
await _controller.setVolume(0.0);
}
if (isVideo) {
final File file = await ImagePicker.pickVideo(source: source);
await _playVideo(file);
} else {
try {
_imageFile = await ImagePicker.pickImage(source: source);
List<int> imageBytes = await _imageFile.readAsBytes();
String base64Image = base64Encode(imageBytes);
print(base64Image);
setState(() {});
} catch (e) {
_pickImageError = e;
}
}
}
#override
void deactivate() {
if (_controller != null) {
_controller.setVolume(0.0);
_controller.pause();
}
super.deactivate();
}
#override
void dispose() {
_disposeVideoController();
super.dispose();
}
Future<void> _disposeVideoController() async {
if (_controller != null) {
await _controller.dispose();
_controller = null;
}
}
Widget _previewVideo() {
final Text retrieveError = _getRetrieveErrorWidget();
if (retrieveError != null) {
return retrieveError;
}
if (_controller == null) {
return const Text(
'You have not yet picked a video',
textAlign: TextAlign.center,
);
}
return Padding(
padding: const EdgeInsets.all(10.0),
child: AspectRatioVideo(_controller),
);
}
Widget _previewImage() {
final Text retrieveError = _getRetrieveErrorWidget();
if (retrieveError != null) {
return retrieveError;
}
if (_imageFile != null) {
return Image.file(_imageFile);
} else if (_pickImageError != null) {
return Text(
'Pick image error: $_pickImageError',
textAlign: TextAlign.center,
);
} else {
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
}
}
Future<void> retrieveLostData() async {
final LostDataResponse response = await ImagePicker.retrieveLostData();
if (response.isEmpty) {
return;
}
if (response.file != null) {
if (response.type == RetrieveType.video) {
isVideo = true;
await _playVideo(response.file);
} else {
isVideo = false;
setState(() {
_imageFile = response.file;
});
}
} else {
_retrieveDataError = response.exception.code;
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Platform.isAndroid
? FutureBuilder<void>(
future: retrieveLostData(),
builder: (BuildContext context, AsyncSnapshot<void> snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
case ConnectionState.waiting:
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
case ConnectionState.done:
return isVideo ? _previewVideo() : _previewImage();
default:
if (snapshot.hasError) {
return Text(
'Pick image/video error: ${snapshot.error}}',
textAlign: TextAlign.center,
);
} else {
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
}
}
},
)
: (isVideo ? _previewVideo() : _previewImage()),
),
floatingActionButton: Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
FloatingActionButton(
onPressed: () {
isVideo = false;
_onImageButtonPressed(ImageSource.gallery);
},
heroTag: 'image0',
tooltip: 'Pick Image from gallery',
child: const Icon(Icons.photo_library),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
onPressed: () {
isVideo = false;
_onImageButtonPressed(ImageSource.camera);
},
heroTag: 'image1',
tooltip: 'Take a Photo',
child: const Icon(Icons.camera_alt),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
backgroundColor: Colors.red,
onPressed: () {
isVideo = true;
_onImageButtonPressed(ImageSource.gallery);
},
heroTag: 'video0',
tooltip: 'Pick Video from gallery',
child: const Icon(Icons.video_library),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
backgroundColor: Colors.red,
onPressed: () {
isVideo = true;
_onImageButtonPressed(ImageSource.camera);
},
heroTag: 'video1',
tooltip: 'Take a Video',
child: const Icon(Icons.videocam),
),
),
],
),
);
}
Text _getRetrieveErrorWidget() {
if (_retrieveDataError != null) {
final Text result = Text(_retrieveDataError);
_retrieveDataError = null;
return result;
}
return null;
}
}
class AspectRatioVideo extends StatefulWidget {
AspectRatioVideo(this.controller);
final VideoPlayerController controller;
#override
AspectRatioVideoState createState() => AspectRatioVideoState();
}
class AspectRatioVideoState extends State<AspectRatioVideo> {
VideoPlayerController get controller => widget.controller;
bool initialized = false;
void _onVideoControllerUpdate() {
if (!mounted) {
return;
}
if (initialized != controller.value.initialized) {
initialized = controller.value.initialized;
setState(() {});
}
}
#override
void initState() {
super.initState();
controller.addListener(_onVideoControllerUpdate);
}
#override
void dispose() {
controller.removeListener(_onVideoControllerUpdate);
super.dispose();
}
#override
Widget build(BuildContext context) {
if (initialized) {
return Center(
child: AspectRatio(
aspectRatio: controller.value?.aspectRatio,
child: VideoPlayer(controller),
),
);
} else {
return Container();
}
}
}

Flutter Directory.systemTemp is not working in the release apk

I'm trying to capture an image from camera and save it in cache(i.e., Directory.systemTemp available from dart.io package). It is working fine in debug mode. But when I build the release apk and install, it is not working. This is the code:
import 'dart:async';
import 'dart:io';
import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
class CameraExampleHome extends StatefulWidget {
#override
_CameraExampleHomeState createState() {
return new _CameraExampleHomeState();
}
}
/// Returns a suitable camera icon for [direction].
IconData getCameraLensIcon(CameraLensDirection direction) {
switch (direction) {
case CameraLensDirection.back:
return Icons.camera_rear;
case CameraLensDirection.front:
return Icons.camera_front;
case CameraLensDirection.external:
return Icons.camera;
}
throw new ArgumentError('Unknown lens direction');
}
void logError(String code, String message) =>
print('Error: $code\nError Message: $message');
class _CameraExampleHomeState extends State<CameraExampleHome> {
CameraController controller;
String imagePath;
final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
Future<List<CameraDescription>> getCameras() async {
return await availableCameras();
}
#override
Widget build(BuildContext context) {
return new Scaffold(
key: _scaffoldKey,
appBar: new AppBar(
title: const Text('Camera example'),
),
body: FutureBuilder(
future: getCameras(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
case ConnectionState.waiting:
return new Text('loading...');
default:
if (snapshot.hasError)
return new Text('Error: ${snapshot.error}');
else {
if (snapshot.hasData)
return createCameraView(context, snapshot);
else
return new Text('Null');
}
}
},
),
);
}
/// Display the preview from the camera (or a message if the preview is not available).
Widget _cameraPreviewWidget() {
if (controller == null || !controller.value.isInitialized) {
return const Text(
'Tap a camera',
style: const TextStyle(
color: Colors.white,
fontSize: 24.0,
fontWeight: FontWeight.w900,
),
);
} else {
return new AspectRatio(
aspectRatio: controller.value.aspectRatio,
child: new CameraPreview(controller),
);
}
}
/// Display the thumbnail of the captured image or video
/// Display the control bar with buttons to take pictures and record videos.
Widget _captureControlRowWidget() {
return new Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
mainAxisSize: MainAxisSize.max,
children: <Widget>[
new IconButton(
icon: const Icon(Icons.camera_alt),
color: Colors.blue,
onPressed: controller != null &&
controller.value.isInitialized &&
!controller.value.isRecordingVideo
? onTakePictureButtonPressed
: null,
),
],
);
}
/// Display a row of toggle to select the camera (or a message if no camera is available).
Widget _cameraTogglesRowWidget(var cameras) {
final List<Widget> toggles = <Widget>[];
if (cameras.isEmpty) {
return const Text('No camera found');
} else {
for (CameraDescription cameraDescription in cameras) {
toggles.add(
new SizedBox(
width: 90.0,
child: new RadioListTile<CameraDescription>(
title:
new Icon(getCameraLensIcon(cameraDescription.lensDirection)),
groupValue: controller?.description,
value: cameraDescription,
onChanged: controller != null && controller.value.isRecordingVideo
? null
: onNewCameraSelected,
),
),
);
}
}
return new Row(children: toggles);
}
String timestamp() => new DateTime.now().millisecondsSinceEpoch.toString();
void showInSnackBar(String message) {
_scaffoldKey.currentState
.showSnackBar(new SnackBar(content: new Text(message)));
}
void onNewCameraSelected(CameraDescription cameraDescription) async {
if (controller != null) {
await controller.dispose();
}
controller = new CameraController(cameraDescription, ResolutionPreset.high);
// If the controller is updated then update the UI.
controller.addListener(() {
if (mounted) setState(() {});
if (controller.value.hasError) {
showInSnackBar('Camera error ${controller.value.errorDescription}');
}
});
try {
await controller.initialize();
} on CameraException catch (e) {
_showCameraException(e);
}
if (mounted) {
setState(() {});
}
}
void onTakePictureButtonPressed() {
takePicture().then((String filePath) {
if (mounted) {
setState(() {
imagePath = filePath;
// videoController?.dispose();
// videoController = null;
});
if (filePath != null) showInSnackBar('Picture saved to $filePath');
}
});
}
Future<String> takePicture() async {
if (!controller.value.isInitialized) {
showInSnackBar('Error: select a camera first.');
return null;
}
//final Directory extDir = await getApplicationDocumentsDirectory();
final Directory extDir = Directory.systemTemp;
final String dirPath = '${extDir.path}/Pictures/flutter_test';
await new Directory(dirPath).create(recursive: true);
final String filePath = '$dirPath/${timestamp()}.jpg';
if (controller.value.isTakingPicture) {
// A capture is already pending, do nothing.
return null;
}
try {
await controller.takePicture(filePath);
} on CameraException catch (e) {
_showCameraException(e);
return null;
}
return filePath;
}
void _showCameraException(CameraException e) {
logError(e.code, e.description);
showInSnackBar('Error: ${e.code}\n${e.description}');
}
Widget createCameraView(BuildContext context, AsyncSnapshot snapshot) {
return new Column(
children: <Widget>[
new Expanded(
child: new Container(
width: MediaQuery.of(context).size.width,
child: _cameraPreviewWidget(),
),
),
_captureControlRowWidget(),
new Padding(
padding: const EdgeInsets.all(5.0),
child: new Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
_cameraTogglesRowWidget(snapshot.data),
//_thumbnailWidget(),
],
),
),
],
);
}
}
class CameraApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
home: new CameraExampleHome(),
);
}
}
List<CameraDescription> cameras;
void main() {
// Fetch the available cameras before initializing the app.
runApp(new CameraApp());
}
I've tried setting the directory to await getApplicationDocumentsDirectory() like this:
final Directory extDir = await getApplicationDocumentsDirectory();
//final Directory extDir = Directory.systemTemp;
final String dirPath = '${extDir.path}/Pictures/flutter_test';
await new Directory(dirPath).create(recursive: true);
final String filePath = '$dirPath/${timestamp()}.jpg';
Then the pictures are being saved both in debug mode and the release apk. But the pictures are lost once I relaunch the app. I want them to accessible even after the app is relaunched(that is the main reason why I want to use cache).
So what's going wrong when I try to save to cache in release build of the app?

use the path_provider package instead to get the temp path https://pub.dartlang.org/packages/path_provider
Directory tempDir = await getTemporaryDirectory();
String tempPath = tempDir.path;
Directory.systemTemp is only supposed to be used on the server/console.