Exporting a Flutter List to CSV file - flutter

Question

I have this screen which lists the items of a class into ListView. What I would want is to have the button (FloatingActionButton in the code) that would export that list to a CSV file. I have the code of what I think it should look, but my issue is that I don't know how to use onPressed on the button in order to export, for now it is null, but it should call the getCSV() function with something in it. Here's the code:
class MailListAdmin extends StatefulWidget {
#override
_MailListAdminState createState() => _MailListAdminState();
}
class _MailListAdminState extends State<MailListAdmin> {
List<String> list = [];
List<Email> finalExport;
#override
void initState() {
super.initState();
DatabaseProvider.db.getMail().then(
(mailList) {
BlocProvider.of<MailBloc>(context).add(SetMail(mailList));
},
);
}
getCsv(List<Email> mailList) async {
List<List<dynamic>> rows = List<List<dynamic>>();
for (int i = 0; i < mailList.length; i++) {
List<dynamic> row = List();
row.add(mailList[i].id);
row.add(mailList[i].email);
rows.add(row);
setState(() {
mailList = finalExport;
});
print(rows);
}
await SimplePermissions.requestPermission(Permission.WriteExternalStorage);
bool checkPermission = await SimplePermissions.checkPermission(
Permission.WriteExternalStorage);
if (checkPermission) {
String dir =
(await getExternalStorageDirectory()).absolute.path + "/documents";
String file = "$dir";
File f = new File(file + "filename.csv");
String csv = const ListToCsvConverter().convert(rows);
f.writeAsString(csv);
}
}
//-------------------------------------
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.blueGrey[900],
title: Text('Newsletter Users'),
actions: [
Padding(
padding: EdgeInsets.only(right: 20.0),
child: Badge(
child: Text('Copied ' + list.length.toString()),
showBadge: false)),
],
),
body: Container(
child: BlocConsumer<MailBloc, List<Email>>(
builder: (context, mailList) {
return ListView.separated(
itemCount: mailList.length,
itemBuilder: (BuildContext context, int index) {
Email mail = mailList[index];
return Card(
child: ListTile(
leading: GestureDetector(
child: Icon(Icons.copy),
onTap: () {
FlutterClipboard.copy(mail.email);
print('Copied ${mail.email}!');
Scaffold.of(context).showSnackBar(SnackBar(
backgroundColor: Colors.grey[600],
duration: Duration(milliseconds: 1000),
content: Text(
'${mail.email} Copied To Clipboard!',
style: TextStyle(fontSize: 20.0),
),
));
list.add(mail.email);
setState(() {
list.length.toString();
});
print(mail.email);
print(list);
}),
trailing: Icon(Icons.delete),
onTap: () {
DatabaseProvider.db.deleteMail(mail.id).then((_) {
BlocProvider.of<MailBloc>(context).add(
DeleteMail(index),
);
});
list.remove(mail.email);
print(list);
setState(() {
list.length.toString();
});
},
title: Text(
mail.email,
style: TextStyle(fontSize: 20.0),
),
),
);
},
separatorBuilder: (BuildContext context, int index) =>
Divider(color: Colors.black),
);
},
listener: (BuildContext context, mailList) {},
),
),
floatingActionButton: FloatingActionButton(
child: Text('Export'),
onPressed: () =>
null, //im not sure how to add the mailList to getCsv(???)
),
);
}
}
Check the export button, where I am not sure how to activate it with getCSV function. Also, how would I access the saved CSV file after it is saved (where would it be saved in the device?)

Answer 1

Try the following steps:
Create a new list in the class.
Assign it to the mail list from the BlocConsumer.
Then use the list in onPressed by passing it to getCsv method.
The Implementation
theEmails is the new list.
class _MailListAdminState extends State<MailListAdmin> {
List<String> list = [];
List<Email> finalExport;
#override
void initState() {
super.initState();
DatabaseProvider.db.getMail().then(
(mailList) {
BlocProvider.of<MailBloc>(context).add(SetMail(mailList));
},
);
}
List<Email> theEmails = [];
getCsv(List<Email> mailList) async {
List<List<dynamic>> rows = List<List<dynamic>>();
for (int i = 0; i < mailList.length; i++) {
List<dynamic> row = List();
row.add(mailList[i].id);
row.add(mailList[i].email);
rows.add(row);
setState(() {
mailList = finalExport;
});
print(rows);
}
await SimplePermissions.requestPermission(Permission.WriteExternalStorage);
bool checkPermission = await SimplePermissions.checkPermission(
Permission.WriteExternalStorage);
if (checkPermission) {
String dir =
(await getExternalStorageDirectory()).absolute.path + "/documents";
String file = "$dir";
File f = new File(file + "filename.csv");
String csv = const ListToCsvConverter().convert(rows);
f.writeAsString(csv);
}
}
//-------------------------------------
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.blueGrey[900],
title: Text('Newsletter Users'),
actions: [
Padding(
padding: EdgeInsets.only(right: 20.0),
child: Badge(
child: Text('Copied ' + list.length.toString()),
showBadge: false)),
],
),
body: Container(
child: BlocConsumer<MailBloc, List<Email>>(
builder: (context, mailList) {
theEmails = mailList;
return ListView.separated(
itemCount: mailList.length,
itemBuilder: (BuildContext context, int index) {
Email mail = mailList[index];
return Card(
child: ListTile(
leading: GestureDetector(
child: Icon(Icons.copy),
onTap: () {
FlutterClipboard.copy(mail.email);
print('Copied ${mail.email}!');
Scaffold.of(context).showSnackBar(SnackBar(
backgroundColor: Colors.grey[600],
duration: Duration(milliseconds: 1000),
content: Text(
'${mail.email} Copied To Clipboard!',
style: TextStyle(fontSize: 20.0),
),
));
list.add(mail.email);
setState(() {
list.length.toString();
});
print(mail.email);
print(list);
}),
trailing: Icon(Icons.delete),
onTap: () {
DatabaseProvider.db.deleteMail(mail.id).then((_) {
BlocProvider.of<MailBloc>(context).add(
DeleteMail(index),
);
});
list.remove(mail.email);
print(list);
setState(() {
list.length.toString();
});
},
title: Text(
mail.email,
style: TextStyle(fontSize: 20.0),
),
),
);
},
separatorBuilder: (BuildContext context, int index) =>
Divider(color: Colors.black),
);
},
listener: (BuildContext context, mailList) {},
),
),
floatingActionButton: FloatingActionButton(
child: Text('Export'),
onPressed: (){
getCsv(theEmails);
}, //im not sure how to add the mailList to getCsv(???)
),
);
}
}