How to parse ICalendar format in Dart?

Question

I need to parse iCal format in Flutter and I don't find any package for do it. Someone can tell me if it exist any solution for solve my problem?

Did you get a solution to this? I am likely going to do it in the next couple of weeks but obviously would prefer to save some time. It would be ideal if it could be a Flutter plugin! — brindy, Nov 01 '19 at 23:31
Not yet, but I am working on an implementation in my spare time. I wouldn't hold your breath though :) — brindy, Nov 27 '19 at 23:52
Nothing worth sharing tbh. I just did something crude as a PoC. The project was supposed to kick off properly in March but got canned because of Covid :( — brindy, Oct 05 '20 at 10:56

score 2 · Answer 1 · answered Oct 26 '20 at 20:07

I don't know if you still have your issue but I've just released a package to parse iCalendar format in pure dart.

https://pub.dev/packages/icalendar_parser

It is still in early development stage but might help you with your problem.

Here is an example on how you could use the package:

import 'package:icalendar_parser/icalendar_parser.dart';

// Parsing from an ICS String (ex: if you are getting data from an API)
final iCalParsed = ICalendar.fromString(yourIcsString);

// Parsing from an ICS List<String> (ex: if you are reading data from a file)
final iCalParsed2 = ICalendar.fromLines(icsFileLines);

Here is a full example I've made in Flutter:

import 'dart:core';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart' show rootBundle;
import 'package:icalendar_parser/icalendar_parser.dart';
import 'package:path_provider/path_provider.dart';
import 'package:path/path.dart' as p;

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  ICalendar _iCalendar;
  bool _isLoading = false;

  Future<void> _getAssetsFile(String assetName) async {
    setState(() => _isLoading = true);
    try {
      final directory = await getTemporaryDirectory();
      final path = p.join(directory.path, assetName);
      final data = await rootBundle.load('assets/$assetName');
      final bytes =
          data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
      final file = await File(path).writeAsBytes(bytes);
      final lines = await file.readAsLines();
      setState(() {
        _iCalendar = ICalendar.fromLines(lines);
        _isLoading = false;
      });
    } catch (e) {
      setState(() => _isLoading = false);
      throw 'Error: $e';
    }
  }

  Widget _generateTextContent() {
    final style = const TextStyle(color: Colors.black);
    return RichText(
      text: TextSpan(
        children: [
          TextSpan(
              text: 'VERSION: ${_iCalendar.version}\n',
              style: style.copyWith(fontWeight: FontWeight.bold)),
          TextSpan(
              text: 'PRODID: ${_iCalendar.prodid}\n',
              style: style.copyWith(fontWeight: FontWeight.bold)),
          TextSpan(
              children: _iCalendar.data
                  .map((e) => TextSpan(
                        children: e.keys
                            .map((f) => TextSpan(children: [
                                  TextSpan(
                                      text: '${f.toUpperCase()}: ',
                                      style: style.copyWith(
                                          fontWeight: FontWeight.bold)),
                                  TextSpan(text: '${e[f]}\n')
                                ]))
                            .toList(),
                      ))
                  .toList()),
        ],
        style: style,
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(16),
        child: Column(
          children: [
            if (_isLoading || _iCalendar == null)
              const Center(child: CircularProgressIndicator())
            else
              _generateTextContent(),
            RaisedButton(
              child: const Text('Load File 1'),
              onPressed: () => _getAssetsFile('calendar.ics'),
            ),
            RaisedButton(
              child: const Text('Load File 2'),
              onPressed: () => _getAssetsFile('calendar2.ics'),
            ),
          ],
        ),
      ),
    );
  }
}

score 0 · Answer 2 · answered Jan 15 '20 at 18:48

To parse/get each platform's calendar?

A quick search of https://pub.dev/packages?q=calendar shows some possible candidates:

Also other related stack posts:

Adding an event to a calendar from Flutter app, this refers to device_calendar plugin
How can I create events in local calendar by Flutter?, this refers to add_2_calendar plugin

If you're not satisfied with the existing plugins, then yes, don't hold your breath, but get to work on your own through custom platform-specific code.

How to parse ICalendar format in Dart?

2 Answers2