Share data while the Internet is available using flutter - flutter

Question

I have a query I would like to store some data in the cache in the event that the phone is not connected to the Internet and when I connect to the Internet, it is sent to the server. I would like to know the best scenario for this case...
And thank u.

Answer 1

You can try saving the data to the server and on failure you can write it in cache. Like
var response = await http.post(Uri.parse("api url here"),
body: json.encode(body),
);
if(response.statusCode != 200)
{
//save data in local like for example
SharedPreferences prefs = await SharedPreferences.getInstance();
prefs.setString("apiBody", json.encode(body);
}

Answer 2

If you need to store or receive a large amount of data, consider to store this datas in a localdatabase like sqflite: https://pub.dev/packages/sqflite
base on SQLLite, you can store and manipulate data with SQL queries.
Here is an example DB helper call that manipulate customer datas:
class DBProvider {
DBProvider._();
static final DBProvider db = DBProvider._();
late Database _database;
Future<Database> get database async {
_database = await initDB();
return _database;
}
initDB() async {
Directory documentsDirectory = await getApplicationDocumentsDirectory();
String path = join(
documentsDirectory.path,
"andidoor.db",
);
return await openDatabase(
path,
version: 2,
onOpen: (db) {},
onCreate: createDatabase,
onUpgrade: upgradeDatabase,
);
}
upgradeDatabase(Database db, int oldVersion, int newVersion) async {
print('Upgrade Database ...');
}
createDatabase(Database db, int version) async {
print('Create Database ...');
await db.execute("CREATE TABLE customers ("
"id INTEGER PRIMARY KEY,"
"user_id INTEGER,"
"company TEXT,"
"address_1 TEXT,"
"address_2 TEXT,"
"address_3 TEXT,"
"zipcode TEXT,"
"city TEXT,"
"country TEXT,"
"email TEXT,"
"phone TEXT,"
"status INTEGER,"
"synced TEXT"
")");
/**
* Customers helper functions
*/
Future<List<dynamic>> getCustomers() async {
Database db = await database;
return await db.rawQuery('SELECT * FROM customers ');
}
Future<void> populateCustomers(List<dynamic> customers) async {
final completer = Completer();
await deleteAllcustomers();
for (var i = 0; i < customers.length; i++) {
await addCustomer(Customer.fromMap(customers[i]), true);
}
completer.complete();
return completer.future;
}
Future<dynamic> deleteAllcustomers() async {
Database db = await database;
return await db.rawQuery('DELETE FROM customers');
}
Future<dynamic> deleteCustomer(String customerID) async {
final db = await database;
return db.delete(
"customers",
where: "id = ? ",
whereArgs: [customerID],
);
}
}
And in other dart file just use like this:
final db = DBProvider.db;
List<dynamic> allDatas = [];
allDatas = await db.getCustomers();