Toggle Bar In Flutter

Toggle Bar In Flutter :

Screenshot :

toggle_bar.dart

library toggle_bar;

import 'dart:collection';

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';

class ToggleBar extends StatefulWidget {
  final TextStyle labelTextStyle;
  final Color backgroundColor;
  final BoxBorder backgroundBorder;
  final Color selectedTabColor;
  final Color selectedTextColor;
  final Color textColor;
  final List<String> labels;
  final Function(int) onSelectionUpdated;

  ToggleBar(
      {@required this.labels,
      this.backgroundColor = Colors.black,
      this.backgroundBorder,
      this.selectedTabColor = Colors.deepPurple,
      this.selectedTextColor = Colors.white,
      this.textColor = Colors.black,
      this.labelTextStyle = const TextStyle(),
      this.onSelectionUpdated});

  @override
  State<StatefulWidget> createState() {
    return _ToggleBarState();
  }
}

class _ToggleBarState extends State<ToggleBar> {
  LinkedHashMap<String, bool> _hashMap = LinkedHashMap();
  int _selectedIndex = 0;

  @override
  void initState() {
    _hashMap = LinkedHashMap.fromIterable(widget.labels,
        value: (value) => value = false);
    _hashMap[widget.labels[0]] = true;

    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
        height: 48,
        margin: EdgeInsets.all(8.0),
        padding: EdgeInsets.all(8.0),
        decoration: BoxDecoration(
            color: widget.backgroundColor,
            border: widget.backgroundBorder,
            borderRadius: BorderRadius.circular(50)),
        child: ListView.builder(
            itemCount: widget.labels.length,
            scrollDirection: Axis.horizontal,
            itemBuilder: (context, index) {
              return GestureDetector(
                  child: Container(
                      width: (MediaQuery.of(context).size.width - 32) /
                          widget.labels.length,
                      padding:
                          EdgeInsets.only(left: 8, right: 8, top: 8, bottom: 8),
                      child: Text(_hashMap.keys.elementAt(index),
                          textAlign: TextAlign.center,
                          style: widget.labelTextStyle.apply(
                              color: _hashMap.values.elementAt(index)
                                  ? widget.selectedTextColor
                                  : widget.textColor)),
                      decoration: BoxDecoration(
                          color: _hashMap.values.elementAt(index)
                              ? widget.selectedTabColor
                              : null,
                          borderRadius: BorderRadius.circular(50))),
                  onHorizontalDragUpdate: (dragUpdate) async {
                    int calculatedIndex = ((widget.labels.length *
                                    (dragUpdate.globalPosition.dx /
                                        (MediaQuery.of(context).size.width -
                                            32)))
                                .round() -
                            1)
                        .clamp(0, widget.labels.length - 1);

                    if (calculatedIndex != _selectedIndex) {
                      _updateSelection(calculatedIndex);
                    }
                  },
                  onTap: () async {
                    if (index != _selectedIndex) {
                      _updateSelection(index);
                    }
                  });
            }));
  }

  _updateSelection(int index) {
    setState(() {
      _selectedIndex = index;
      widget.onSelectionUpdated(_selectedIndex);
      _hashMap.updateAll((label, selected) => selected = false);
      _hashMap[_hashMap.keys.elementAt(index)] = true;
    });
  }
}

main.dart

import 'package:flutter/material.dart';
import 'toggle_bar.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Tutorial',
      theme: ThemeData(
        primarySwatch: Colors.deepPurple,
      ),
      debugShowCheckedModeBanner: false,
      home: MyHomePage(title: 'Toggle Bar in Flutter'),
    );
  }
}

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

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  List<String> labels = ["Apples", "Bananas", "Oranges", "Papayas"];
  int currentIndex = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            children: <Widget>[
              ToggleBar(
                labels: labels,
                backgroundColor: Colors.grey.withOpacity(0.1),
                onSelectionUpdated: (index) =>
                    setState(() => currentIndex = index),
              ),
              Text(
                labels[currentIndex],
                style: Theme.of(context).textTheme.display1,
              )
            ]));
  }
}

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