import 'package:flutter/material.dart';

class ListPage extends StatefulWidget {
  final String listName;

  ListPage({this.listName}) : super(key: Key(listName));

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

class _ListPageState extends State<ListPage> {
  Map<String, bool> items = {"Butter": true, "Milch": false};

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: new Text(widget.listName),
      ),
      body: ListView(
        padding: EdgeInsets.symmetric(vertical: 8.0),
        children: ListTile.divideTiles(
                context: context,
                tiles: items
                    .map((item, checked) => MapEntry(
                        item,
                        CheckboxListTile(
                          title: Text(item),
                          controlAffinity: ListTileControlAffinity.leading,
                          value: checked,
                          onChanged: (bool value) =>
                              setState(() => items[item] = value),
                        )))
                    .values)
            .toList(),
      ),
      floatingActionButton: FloatingActionButton(
          onPressed: () => _addItem(), child: Icon(Icons.add)),
    );
  }

  _addItem() {
    var textController = new TextEditingController();
    showDialog(
      context: context,
      child: new AlertDialog(
        contentPadding: const EdgeInsets.all(16.0),
        content: new Row(children: <Widget>[
          Expanded(
            child: new TextField(
              autofocus: true,
              decoration: new InputDecoration(
                  labelText: 'List Item', hintText: 'eg. Milk'),
              controller: textController,
            ),
          )
        ]),
        actions: <Widget>[
          new FlatButton(
            child: const Text('CANCEL'),
            onPressed: () => Navigator.pop(context),
          ),
          new FlatButton(
            child: const Text('ADD'),
            onPressed: () {
              if (textController.text.isNotEmpty)
                setState(() => items[textController.text] = false);
              Navigator.pop(context);
            },
          )
        ],
      ),
    );
  }
}