Develop Reference

Exception: CameraException(CameraAccess, CAMERA_ERROR (3): waitUntilIdle:1851: Camera 0: Error waiting to drain: Connection timed out (-110))

I am trying to build a screen that will use camera package to get the image stream from the live feed.
my code: -
class CameraView extends StatefulWidget {
CameraView(
{Key? key,
required this.title,
required this.customPaint,
required this.onImage,
this.initialDirection = CameraLensDirection.back})
: super(key: key);
final String title;
final CustomPaint? customPaint;
final Function(InputImage inputImage) onImage;
final CameraLensDirection initialDirection;
#override
_CameraViewState createState() => _CameraViewState();
}
class _CameraViewState extends State<CameraView> {
String _numberplate = 'Unknown';
ScreenMode _mode = ScreenMode.liveFeed;
CameraController? _controller;
File? _image;
int _cameraIndex = 0;
double zoomLevel = 0.0, minZoomLevel = 0.0, maxZoomLevel = 0.0;
List<String> dialogsShown = [];
#override
void initState() {
super.initState();
initNpGroups();
// _imagePicker = ImagePicker();
for (var i = 0; i < cameras.length; i++) {
if (cameras[i].lensDirection == widget.initialDirection) {
_cameraIndex = i;
}
}
_startLiveFeed();
}
#override
void dispose() {
_stopLiveFeed();
_controller?.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: ListView(
children: [
],
),
);
}
Future _startLiveFeed() async {
final camera = cameras[0];
_controller = CameraController(
camera,
ResolutionPreset.low,
enableAudio: false,
);
_controller?.initialize().then((_) async {
if (!mounted) {
return;
}
setState(() {});
_controller?.getMinZoomLevel().then((value) {
zoomLevel = value;
minZoomLevel = value;
});
_controller?.getMaxZoomLevel().then((value) {
maxZoomLevel = value;
});
if (_controller!.value.isInitialized == true) {
_controller?.startImageStream(_processCameraImage);
setState(() {});
} else {
await _controller?.initialize();
_controller?.startImageStream(_processCameraImage);
setState(() {});
}
});
}
Future _processCameraImage(CameraImage image) async {
textFound.length > 6 ? stopLiveFeed() : print(textFound);
final WriteBuffer allBytes = WriteBuffer();
for (Plane plane in image.planes) {
allBytes.putUint8List(plane.bytes);
}
final bytes = allBytes.done().buffer.asUint8List();
final Size imageSize =
Size(image.width.toDouble(), image.height.toDouble());
final camera = cameras[_cameraIndex];
final imageRotation =
InputImageRotationMethods.fromRawValue(camera.sensorOrientation) ??
InputImageRotation.Rotation_0deg;
final inputImageFormat =
InputImageFormatMethods.fromRawValue(image.format.raw) ??
InputImageFormat.NV21;
final planeData = image.planes.map(
(Plane plane) {
return InputImagePlaneMetadata(
bytesPerRow: plane.bytesPerRow,
height: plane.height,
width: plane.width,
);
},
).toList();
final inputImageData = InputImageData(
size: imageSize,
imageRotation: imageRotation,
inputImageFormat: inputImageFormat,
planeData: planeData,
);
final inputImage =
InputImage.fromBytes(bytes: bytes, inputImageData: inputImageData);
widget.onImage(inputImage);
}
}
Error : - [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: CameraException(CameraAccess, CAMERA_ERROR (3): waitUntilIdle:1851: Camera 0: Error waiting to drain: Connection timed out (-110))
one 1 in 2 times I get the undesired output.
undesired output : - working properly
desired output : - screen turns black and unresponsive
full code: - https://drive.google.com/file/d/1T5YxEXEc7ajVw3__pt1ahFXt6cypnCll/view?usp=sharing
Does anyone know how to solve this?

save a temp file to download file Android/IOS in flutter

I have a question, I am using Path-provider to generate a path for a new generated PDF file from my App… but path provider is storing the file in the App folder & after closing the app the file will be deleted, I am using getExternalStorageDirectory… how can I save that file to downloads when selected.
Anybody can help me?
just small explanation... the PDF file will be viewed from the App using
flutter_full_pdf_viewer
then from that page I need to let the user select if he wants to save the file or close the hall file.
This is the code for the file save
try {
final dir = await getExternalStorageDirectory();
String documentPath = dir.path;
fullPath = "$documentPath/$fileName";
final file = File('$fullPath');
await file.writeAsBytes(await pdf.save());
print('XXXXXXXXX$fileName');
return file;
} catch (e) {
// print('we have a problem');
}
print(fullPath);
}
And this is the PDFViewer page code
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: PDFViewerScaffold(
appBar: AppBar(
title: Text('PDF page'),
actions: <Widget>[
IconButton(
icon: Icon(Icons.share),
onPressed: () {
Share.shareFiles(
['$path'],
);
print('iiiiiiiiiiiiii$path');
},
),
IconButton(
icon: Icon(Icons.save),
onPressed: () {},
),
],
),
path: path,
),
),
);
}
}
============================================================================
after I modified the code now it looks like this for the PDF_save Page (for Methods)
Future<bool> saveFolder(String fileName) async {
Directory directory;
try {
if (Platform.isAndroid) {
if (await _requestPermission(Permission.storage)) {
directory = await getExternalStorageDirectory();
String newPath = "";
print('ZZZZZZZZzzzzZZZZz$directory');
List<String> paths = directory.path.split("/");
for (int x = 1; x < paths.length; x++) {
String folder = paths[x];
if (folder != "Android") {
newPath += "/" + folder;
} else {
break;
}
}
newPath = newPath + "/SAMApp";
directory = Directory(newPath);
print('AAAAAAAAAAAAAAAA$newPath');
print('AAAAAAAAAAAAAAAA$fileName');
} else {
return false;
}
} else {
if (await _requestPermission(Permission.photos)) {
directory = await getTemporaryDirectory();
} else {
return false;
}
}
File saveFile = File(directory.path + "/$fileName");
if (!await directory.exists()) {
await directory.create(recursive: true);
}
if (await directory.exists()) {
// await dio.download(saveFile.path, onReceiveProgress: (value1, value2) {
// setState(() {
// progress = value1 / value2;
// });
// });
// if (Platform.isIOS) {
// await ImageGallerySaver.saveFile(saveFile.path,
// isReturnPathOfIOS: true);
// }
File savedFile = File(directory.path + "/$fileName");
var savedPath = directory.path + "/$fileName";
print('$savedPath');
print('$savedFile');
savedFile.writeAsBytesSync(byteList);
if (savedPath != null) {
print('NO saved Path');
// await Navigator.pushReplacement(
// context,
// MaterialPageRoute(
// builder: (context) => SharePage(
// imageFilebytes: pngBytes,
// imagePath: savedPath,
// )),
// );
} else {
print("waiting for savedpath");
}
return true;
}
return false;
} catch (e) {
print(e);
return false;
}
}
did I made something wrong??

This is worked to save the image. It can be useful for you.
Future<bool> saveFile(var byteList, BuildContext context) async {
Directory storageDir;
try {
if (await requestPermission(Permission.storage)) {
storageDir = await getExternalStorageDirectory();
String newPath = '';
List<String> folders = storageDir.path.split('/');
for (int x = 1; x < folders.length; x++) {
String folder = folders[x];
if (folder != 'Android') {
newPath += '/' + folder;
} else {
break;
}
}
newPath = newPath + '/xyz';
storageDir = Directory(newPath);
} else {
if (await requestPermission(Permission.photos)) {
storageDir = await getTemporaryDirectory();
} else {
return false;
}
}
if (!await storageDir.exists()) {
await storageDir.create(recursive: true);
}
if (await storageDir.exists()) {
//List<int> bytesSync = widget.pickedImage.readAsBytesSync();
DateTime date = DateTime.now();
String baseFileName = 'abc' + date.toString() + ".jpg";
File savedFile = File(storageDir.path + "/$baseFileName");
savedPath = storageDir.path + "/$baseFileName";
savedFile.writeAsBytesSync(byteList);
if (savedPath != null) {
await Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => SharePage(
imageFilebytes: pngBytes,
imagePath: savedPath,
)));
} else {
print("waiting for savedpath");
}
return true;
}
} catch (e) {
print(e);
}
return false;
}

setState() not rendring the variable changes on the screen

I am trying to create a simple flutter project for learning. I need to write the tapped student name on the screen but setState isn't working. It's changing the variable but not rendering on the screen. -Photo-
Here is what I want. For example when I click on Name3 LastName3 I want it to write "Name3 LastName3" on the bottom.
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
#override
Widget build(BuildContext context) {
// TODO: implement build
return Scaffold(
appBar: AppBar(
title: Text("Student Exam Result System"),
),
body: bodyBuilder(context),
);
}
bodyBuilder(BuildContext context) {
String ChoosedStudent = "";
StudentManager student1 = new StudentManager("Name1", "LastName1", 22,
"https://uifaces.co/our-content/donated/hvaUVob5.jpg");
StudentManager student2 = new StudentManager("Name2", "LastName2", 70,
"https://uifaces.co/our-content/donated/eqUZLcBO.jpg");
StudentManager student3 = new StudentManager("Name3", "LastName3", 55,
"https://uifaces.co/our-content/donated/-oe25tWA.png");
StudentManager student4 = new StudentManager("Name4", "LastName4", 99,
"https://images.generated.photos/ukvWCGJJF8xoZ_rvVSFDLnQ-WDkGw2WsZ53uPPm63M8/rs:fit:512:512/Z3M6Ly9nZW5lcmF0/ZWQtcGhvdG9zLzA3/OTI0MTAuanBn.jpg");
StudentManager student5 = new StudentManager(
"Name5", "LastName5", 45, "https://thispersondoesnotexist.com/image");
List<StudentManager> StudentList = [
student1,
student2,
student3,
student4,
student5
];
return Column(
children: [
Expanded(
child: ListView.builder(
itemCount: StudentList.length,
itemBuilder: (BuildContext context, int index) {
if (StudentList[index].Grade >= 50) {
StudentList[index].IsPassed = true;
} else if (StudentList[index].Grade < 50) {
StudentList[index].IsPassed = false;
}
return ListTile(
leading: CircleAvatar(
backgroundImage:
NetworkImage(StudentList[index].PhotoURL),
),
title: Text(StudentList[index].Name +
" " +
StudentList[index].Surname),
subtitle: Text(
"${StudentList[index].Name} named students grade is "
"${StudentList[index].Grade}, ${StudentList[index].AlphebaticalGrade}"),
isThreeLine: true,
trailing: buildStatusIcon(StudentList[index].IsPassed),
onTap: () {
setState(() {
ChoosedStudent = StudentList[index].Name +
" " +
StudentList[index].Surname;
});
},
);
})),
Text("Student: " + ChoosedStudent),
Center(),
],
);
}
}
Widget buildStatusIcon(bool IsPassed) {
if (IsPassed == true) {
return Icon(Icons.done);
} else if (IsPassed == false) {
return Icon(Icons.warning);
} else {
return Icon(Icons.error);
}
}
I don't know if it's necessary but here is student class:
class StudentManager{
String Name;
String Surname;
int Grade;
String AlphebaticalGrade;
bool IsPassed;
String PhotoURL;
StudentManager(String Name, String Surname, int Grade, String PhotoURL){
this.Grade = Grade;
this.Surname = Surname;
this.Name=Name;
this.PhotoURL = PhotoURL;
if (Grade >= 90 && Grade <= 100) {
AlphebaticalGrade = "A+";
} else if (Grade >= 80 && Grade <= 90) {
AlphebaticalGrade = "A";
} else if (Grade >= 70 && Grade <= 80) {
AlphebaticalGrade = "B+";
} else if (Grade >= 60 && Grade <= 70) {
AlphebaticalGrade = "B";
} else if (Grade >= 50 && Grade <= 60) {
AlphebaticalGrade = "D+";
} else if (Grade >= 40 && Grade <= 50) {
AlphebaticalGrade = "D";
} else if (Grade <= 39 && Grade <= 40) {
AlphebaticalGrade = "F";
} else {
AlphebaticalGrade =
"The grade is unknown please contact with your teacher";
}
}
}
(I know it doesn't have C or C+ notes :D )

class _MyAppState extends State<MyApp> {
String ChoosedStudent = "";
// ↑ As a field, will not be reset during build method call
// ↓ build method called on setState. Any "state" inside build will be lost upon rebuild
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Student Exam Result System"),
),
body: bodyBuilder(context),
);
}
bodyBuilder(BuildContext context) {
// ↓ MOVE THIS UP AS A FIELD
// String ChoosedStudent = "";

you should define String ChoosedStudent = ""; as global variable.
Please try putting it right under class _MyAppState extends State<MyApp> {

What is the correct way to add time picker in flutter app?

In my app, the user needs to select a time manually for a task, but I do not know what is the correct way to use time picker in flutter app and select the time(of a day) manually by the user.

First declare this variable at the class level,
TimeOfDay selectedTime = TimeOfDay.now();
and then call this method -
Future<void> _selectTime(BuildContext context) async {
final TimeOfDay picked_s = await showTimePicker(
context: context,
initialTime: selectedTime, builder: (BuildContext context, Widget child) {
return MediaQuery(
data: MediaQuery.of(context).copyWith(alwaysUse24HourFormat: false),
child: child,
);});
if (picked_s != null && picked_s != selectedTime )
setState(() {
selectedTime = picked_s;
});
}

This code will shows a dialog containing a material design time picker.
Note that a showTimePicker is Future. So, you need to use await to get a time.
TimeOfDay initialTime = TimeOfDay.now();
TimeOfDay pickedTime = await showTimePicker(
context: context,
initialTime: initialTime,
);
Also you could customize your time picker using builder property inside the showTimePicker
TimeOfDay initialTime = TimeOfDay.now();
TimeOfDay pickedTime = await showTimePicker(
context: context,
initialTime: initialTime,
builder: (BuildContext context, Widget child) {
return Directionality(
textDirection: TextDirection.rtl,
child: child,
);
},
);
You can learn more about it on a official documentation here

you can use from flutter_datetime_picker plugin :
FlatButton(
onPressed: () {
DatePicker.showDatePicker(context,
showTitleActions: true,
minTime: DateTime(2018, 3, 5),
maxTime: DateTime(2019, 6, 7), onChanged: (date) {
print('change $date');
}, onConfirm: (date) {
print('confirm $date');
}, currentTime: DateTime.now(), locale: LocaleType.zh);
},
child: Text(
'show date time picker (Chinese)',
style: TextStyle(color: Colors.blue),
));
class CustomPicker extends CommonPickerModel {
String digits(int value, int length) {
return '$value'.padLeft(length, "0");
}
CustomPicker({DateTime currentTime, LocaleType locale}) : super(locale: locale) {
this.currentTime = currentTime ?? DateTime.now();
this.setLeftIndex(this.currentTime.hour);
this.setMiddleIndex(this.currentTime.minute);
this.setRightIndex(this.currentTime.second);
}
#override
String leftStringAtIndex(int index) {
if (index >= 0 && index < 24) {
return this.digits(index, 2);
} else {
return null;
}
}
#override
String middleStringAtIndex(int index) {
if (index >= 0 && index < 60) {
return this.digits(index, 2);
} else {
return null;
}
}
#override
String rightStringAtIndex(int index) {
if (index >= 0 && index < 60) {
return this.digits(index, 2);
} else {
return null;
}
}
#override
String leftDivider() {
return "|";
}
#override
String rightDivider() {
return "|";
}
#override
List<int> layoutProportions() {
return [1, 2, 1];
}
#override
DateTime finalTime() {
return currentTime.isUtc
? DateTime.utc(currentTime.year, currentTime.month, currentTime.day,
this.currentLeftIndex(), this.currentMiddleIndex(),
this.currentRightIndex())
: DateTime(currentTime.year, currentTime.month, currentTime.day,
this.currentLeftIndex(),
this.currentMiddleIndex(), this.currentRightIndex());
}
}

You can use this for timepicker in flutter
Future<void> _selectTime(BuildContext context) async {
TimeOfDay? picked = await showTimePicker(
context: context,
initialTime: TimeOfDay.now(), builder: (BuildContext context, Widget child) {
return MediaQuery(
data: MediaQuery.of(context).copyWith(alwaysUse24HourFormat: false),
child: child,
);});
if (picked != null && picked != TimeOfDay.now() )
}

How to read audio extensions in Flutter and display in a ListView?

How to make a function in Flutter which will Read audio files from SD card and display them to a ListView?

If you're asking about showing list of audio-files - here example of my code:
import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter_app/storage.dart';
import 'package:path_provider/path_provider.dart';
import 'package:simple_permissions/simple_permissions.dart';
class BrowserScaffold extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return _BrowserScaffoldState();
}
}
class _BrowserScaffoldState extends State<BrowserScaffold> {
final List<FileSystemEntity> files = List<FileSystemEntity>();
final savedFiles = Set<File>();
Directory parent;
ScrollController controller = ScrollController();
#override
Widget build(BuildContext context) {
if (parent == null) {
SimplePermissions
.requestPermission(Permission.WriteExternalStorage)
.then((value) {
if (value == PermissionStatus.authorized) {
localPath.then((String value) {
Directory dir = Directory(value);
while (dir.path != dir.parent.path) {
dir.isAbsolute;
dir = dir.parent;
}
parent = dir;
setState(() {
files.addAll(dir.parent.listSync());
sortFiles();
});
});
} else {
SimplePermissions.openSettings();
}
});
}
return Scaffold(
appBar: AppBar(
title: Text('Files'),
actions: <Widget>[
IconButton(icon: Icon(Icons.check), onPressed: apply),
],
),
body: buildList(),
);
}
void sortFiles() {
for (int i = files.length - 1; i >= 0; i--) {
FileSystemEntity entity = files[i];
if (entity is Link) {
files.remove(entity);
} else if (entity is Directory) {
try {
entity.listSync();
} catch (ex) {
print('catch: ${entity.path}, $ex');
files.remove(entity);
}
}
}
files.sort((FileSystemEntity a, FileSystemEntity b) {
if (a is Directory && b is File) return -1;
if (a is File && b is Directory) return 1;
return a.path.compareTo(b.path);
});
}
Widget buildList() {
if (parent == null) return ListView();
bool isRoot = parent.path == parent.parent.path;
return ListView.builder(
itemBuilder: (context, i) {
if (i.isOdd)
return Divider(
height: 4.0,
);
final index = isRoot ? i ~/ 2 : i ~/ 2 - 1;
return buildRow(index);
},
itemCount: isRoot ? files.length * 2 : (files.length + 1) * 2,
controller: controller,
);
}
Widget buildRow(int index) {
if (index == -1) return getRootTile();
FileSystemEntity file = files[index];
if (file is Directory) return getDirectoryTile(file);
if (file is File) return getFileTile(file);
if (file is Link)
return Container(
height: 0.0,
);
return Container(
height: 0.0,
);
}
Widget getRootTile() {
return ListTile(
title: Text('../'),
trailing: Icon(Icons.keyboard_backspace),
onTap: () {
setState(() {
parent = parent.parent;
List<FileSystemEntity> rootList = parent.listSync();
files.clear();
files.addAll(rootList);
sortFiles();
});
},
);
}
Widget getDirectoryTile(Directory dir) {
return ListTile(
title: Text(dir.path.split('/').last),
trailing: Icon(
Icons.folder_open,
color: Colors.grey,
),
onTap: () {
setState(() {
parent = dir;
files.clear();
files.addAll(dir.listSync());
sortFiles();
});
},
);
}
Widget getFileTile(File file) {
bool isSaved = savedFiles.map((file) => file.path).contains(file.path);
final List<String> extensions = <String>[
"MP3",
"WAV",
"AAC",
"WMA",
"AMR",
"OGG",
"MIDI"
];
bool isRightType =
extensions.contains(file.path.split('.').last.toUpperCase());
return ListTile(
title: Text(file.path.split('/').last),
trailing: isRightType
// ignore: missing_required_param
? IconButton(
icon: Icon(
isSaved ? Icons.check_box : Icons.check_box_outline_blank,
color: isSaved ? Colors.blueGrey : Colors.grey,
),
)
: null,
onTap: () {
setState(() {
if (isSaved) {
savedFiles.remove(file);
} else {
savedFiles.add(file);
}
});
},
);
}
void apply() async {
final List<Track> list = List();
list.addAll(savedFiles.map((file) => Track(file.path)));
Navigator.of(context).pop(list);
}
Future<String> get localPath async {
final directory = await getApplicationDocumentsDirectory();
return directory.path;
}
}
In my case I show all files, but only audio is selectable (with checkbox)

if you're talking about being able to identify a file extension, then you first need to install Path and import it:
import 'package:path/path.dart' as p;
then check against this:
String _extension = p.extension(_someFile).split('?').first;

I suggest you read the documentation of Android Studio | Files
You can use fileList() to get an ArrayList
Further, use a for loop to get the names and paths -> file.getName() | file.getPath()