how to convert excel sheet into json in flutter - flutter

Question

how to convert excel sheet into json in flutter.
I have a excel sheet of students names and classes and i want to convert it to json to make it easy to run the app or another way to upload date to firestore.
Future<String> excelToJson() async {
var file = await FilePicker.getFilePath(
type: FileType.custom, allowedExtensions: ['xlsx', 'csv', 'xls']);
var bytes = File(file).readAsBytesSync();
var excel = Excel.decodeBytes(bytes);
int i = 0;
List<dynamic> keys = new List<dynamic>();
List<Map<String, dynamic>> json = new List<Map<String, dynamic>>();
for (var table in excel.tables.keys) {
for (var row in excel.tables[table].rows) {
if (i == 0) {
keys = row;
i++;
} else {
Map<String, dynamic> temp = Map<String, dynamic>();
int j = 0;
String tk = '';
for (var key in keys) {
tk = "\u201C" + key + "\u201D";
temp[tk] = (row[j].runtimeType==String)?"\u201C" + row[j].toString() + "\u201D":row[j];
j++;
}
json.add(temp);
}
}
}
print(json.length);
String fullJson = json.toString().substring(1, json.toString().length - 1);
return fullJson;}
I want to learn how to use this script in my application or another way is more easy and simple
Thanks

Answer 1

Use this methods:
Future<void> excelToJson(String fileName, String fileDirectory,GlobalKey<ScaffoldState> scaffoldKey) async {
ByteData data = await rootBundle.load(fileDirectory);
var bytes = data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
var excel = Excel.decodeBytes(bytes);
int i = 0;
List<dynamic> keys = new List<dynamic>();
List<Map<String, dynamic>> json = new List<Map<String, dynamic>>();
for (var table in excel.tables.keys) {
for (var row in excel.tables[table].rows) {
if (i == 0) {
keys = row;
i++;
} else {
Map<String, dynamic> temp = Map<String, dynamic>();
int j = 0;
String tk = '';
for (var key in keys) {
tk = '"' + key + '"';
temp[tk] = (row[j].runtimeType == String)
? '"' + row[j].toString() + '"'
: row[j];
j++;
}
json.add(temp);
}
}
}
print(json.length);
String fullJson = json.toString().substring(1, json
.toString()
.length - 1);
fullJson = '{ "DATA" : [$fullJson]}';
final directory = await getExternalStorageDirectory();
File file = await File('${directory.path}/$fileName.json').create();
await file.writeAsString(fullJson).then((value) =>
scaffoldKey.currentState
.showSnackBar(SnackBar(content: Text("Completed")))
);
print(file.exists().toString());
}
Future<void> jsonToExcel(String fileName, String fileDirectory,GlobalKey<ScaffoldState> scaffoldKey) async{
String jsonString = await rootBundle.loadString(fileDirectory);
List<dynamic> jsonResult = jsonDecode(jsonString)["DATA"];
var excel = Excel.createExcel();
Sheet sheetObject = excel['Sheet1'];
Map<String,dynamic> result = jsonResult[0];
sheetObject.appendRow(result.keys.toList());
for(int i =0;i<jsonResult.length;i++){
Map<String,dynamic> result = jsonResult[i];
sheetObject.appendRow(result.values.toList());
}
final directory = await getExternalStorageDirectory();
excel.encode().then((onValue) {
File(("${directory.path}/$fileName.xlsx"))
..createSync(recursive: true)
..writeAsBytesSync(onValue);
scaffoldKey.currentState
.showSnackBar(SnackBar(content: Text("Completed")));
});
print(sheetObject);
}

Answer 2

Updated your code just a bit....
Future<String> excelToJson() async {
FilePickerResult result =await FilePicker.platform.pickFiles(type:FileType.custom,allowedExtensions: ['xls','xlsx','csv']);
if (result != null) {
File excelFile = File(result.files.single.path);}
var bytes = File(excelFilePath).readAsBytesSync();
var excel = Excel.decodeBytes(bytes);
int i = 0;
List<dynamic> keys = [];
var jsonMap = [];
for (var table in excel.tables.keys) {
dev.log(table.toString());
for (var row in excel.tables[table].rows) {
dev.log(row.toString());
if (i == 0) {
keys = row;
i++;
} else {
var temp = {};
int j = 0;
String tk = '';
for (var key in keys) {
tk = '\"${key.toString()}\"';
temp[tk] = (row[j].runtimeType == String)
? '\"${row[j].toString()}\"'
: row[j];
j++;
}
jsonMap.add(temp);
}
}
}
dev.log(
jsonMap.length.toString(),
name: 'excel to json',
);
dev.log(jsonMap.toString(), name: 'excel to json');
String fullJson =
jsonMap.toString().substring(1, jsonMap.toString().length - 1);
dev.log(
fullJson.toString(),
name: 'excel to json',
);
return fullJson;
}