encrateia/lib/widgets/athlete_widgets/athlete_body_weight_widget.dart

import 'dart:convert';
import 'dart:io';
import 'package:encrateia/screens/add_weight_screen.dart';
import 'package:encrateia/utils/my_button.dart';
import 'package:flutter/material.dart';
import 'package:encrateia/models/athlete.dart';
import 'package:encrateia/models/weight.dart';
import 'package:encrateia/utils/icon_utils.dart';
import 'package:path_provider/path_provider.dart';
import 'package:csv/csv.dart';
import 'package:intl/intl.dart';

class AthleteBodyWeightWidget extends StatefulWidget {
  final Athlete athlete;

  AthleteBodyWeightWidget({this.athlete});

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

class _AthleteBodyWeightWidgetState extends State<AthleteBodyWeightWidget> {
  List<Weight> weights = [];
  int offset = 0;
  int rows;

  @override
  void initState() {
    getData();
    super.initState();
  }

  @override
  Widget build(context) {
    if (weights != null) {
      if (weights.length > 0) {
        rows = (weights.length < 8) ? weights.length : 8;
        return ListView(
          children: <Widget>[
            DataTable(
              headingRowHeight: kMinInteractiveDimension * 0.80,
              dataRowHeight: kMinInteractiveDimension * 0.80,
              columns: <DataColumn>[
                DataColumn(label: Text("Date")),
                DataColumn(
                  label: Text("Weight in kg"),
                  numeric: true,
                ),
                DataColumn(label: Text("Edit"))
              ],
              rows: weights.sublist(offset, offset + rows).map((Weight weight) {
                return DataRow(
                  key: Key(weight.db.id.toString()),
                  cells: [
                    DataCell(
                        Text(DateFormat("d MMM yyyy").format(weight.db.date))),
                    DataCell(Text(weight.db.value.toString())),
                    DataCell(MyIcon.edit, onTap: () async {
                      await Navigator.push(
                        context,
                        MaterialPageRoute(
                          builder: (context) => AddWeightScreen(weight: weight),
                        ),
                      );
                      getData();
                    })
                  ],
                );
              }).toList(),
            ),
            Padding(
              padding: EdgeInsets.all(10),
              child: Text(
                "${offset + 1} - ${offset + rows} "
                "of ${weights.length} ",
                textAlign: TextAlign.right,
              ),
            ),
            Row(
              children: <Widget>[
                Spacer(),
                MyButton.add(
                    child: Text("New weighting"),
                    onPressed: () async {
                      await Navigator.push(
                        context,
                        MaterialPageRoute(
                          builder: (context) => AddWeightScreen(
                            weight: Weight(athlete: widget.athlete),
                          ),
                        ),
                      );
                      getData();
                    }),
                Spacer(),
                MyButton.navigate(
                  child: Text("<<"),
                  onPressed: (offset == 0)
                      ? null
                      : () => setState(() {
                            offset > 8 ? offset = offset - rows : offset = 0;
                          }),
                ),
                Spacer(),
                MyButton.navigate(
                  child: Text(">>"),
                  onPressed: (offset + rows == weights.length)
                      ? null
                      : () => setState(() {
                            offset + rows < weights.length - rows
                                ? offset = offset + rows
                                : offset = weights.length - rows;
                          }),
                ),
                Spacer(),
              ],
            ),
          ],
        );
      } else {
        return ListView(
          children: <Widget>[
            Padding(
              padding: EdgeInsets.all(25.0),
              child: Text('''
No weight data so far:
                
You can import your historic weight data by putting a weights.csv-file in the App's document directory.
It's the one with a file named "put_your_fit_files_here.txt" inside.

Put one date and weight per line in the following format:
2020-04-28,75.3

Or you can simply enter your current weight using the New Weighting button. 
                '''),
            ),
            Row(
              children: <Widget>[
                Spacer(),
                RaisedButton(
                  // MyIcon.downloadLocal,
                  color: Colors.orange,
                  child: Text("Import Weights"),
                  onPressed: () => importWeights(),
                ),
                Spacer(),
                RaisedButton(
                    color: Colors.green,
                    child: Text("New weighting"),
                    onPressed: () async {
                      await Navigator.push(
                        context,
                        MaterialPageRoute(
                          builder: (context) => AddWeightScreen(
                            weight: Weight(athlete: widget.athlete),
                          ),
                        ),
                      );
                      getData();
                    }),
                Spacer(),
              ],
            )
          ],
        );
      }
    } else {
      return Center(child: Text("loading"));
    }
  }

  getData() async {
    Athlete athlete = widget.athlete;
    weights = await athlete.weights;
    setState(() {});
  }

  importWeights() async {
    Directory directory;
    Weight weight;

    if (Platform.isAndroid) {
      var directories = await getExternalStorageDirectories();
      directory = directories[0];
    } else {
      directory = await getApplicationDocumentsDirectory();
    }
    var pathToFile = directory.path + "/weights.csv";
    var isFile = await FileSystemEntity.isFile(pathToFile);
    if (isFile == true) {
      var input = File(pathToFile).openRead();
      final weightings = await input
          .transform(utf8.decoder)
          .transform(CsvToListConverter(eol: "\n"))
          .toList();
      for (List weighting in weightings) {
        weight = Weight(athlete: widget.athlete);
        weight.db.date = DateTime.utc(
          int.parse(weighting[0].split("-")[0]),
          int.parse(weighting[0].split("-")[1]),
          int.parse(weighting[0].split("-")[2]),
        );
        weight.db.value = weighting[1].toDouble();
        await weight.db.save();
      }
      await getData();
    }
  }
}