overflow_view 0.1.0

A widget displaying children in a line with an overflow indicator at the end if there is not enough space.

example/lib/main.dart

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  final String title;

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

class Avatar {
  const Avatar(this.initials, this.color);
  final String initials;
  final Color color;
}

const List<Avatar> avatars = <Avatar>[
  Avatar('AD', Colors.green),
  Avatar('JG', Colors.pink),
  Avatar('DA', Colors.blue),
  Avatar('JA', Colors.black),
  Avatar('CB', Colors.amber),
  Avatar('RR', Colors.deepPurple),
  Avatar('JD', Colors.pink),
  Avatar('MB', Colors.amberAccent),
  Avatar('AA', Colors.blueAccent),
  Avatar('BA', Colors.tealAccent),
  Avatar('CR', Colors.yellow),
];

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 1;

  void _incrementCounter() {
    setState(() {
      _counter = (_counter + 1).clamp(0, avatars.length - 1);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              'People',
              style: TextStyle(fontSize: 20),
            ),
            SizedBox(height: 20),
            OverflowView(
              spacing: 4,
              children: <Widget>[
                for (int i = 0; i < _counter; i++)
                  AvatarWidget(
                    text: avatars[i].initials,
                    color: avatars[i].color,
                  )
              ],
              builder: (context, remaining) {
                return AvatarWidget(
                  text: '+$remaining',
                  color: Colors.red,
                );
              },
            ),
            SizedBox(height: 20),
            Expanded(
              child: OverflowView(
                direction: Axis.vertical,
                spacing: 4,
                children: <Widget>[
                  for (int i = 0; i < _counter; i++)
                    AvatarWidget(
                      text: avatars[i].initials,
                      color: avatars[i].color,
                    )
                ],
                builder: (context, remaining) {
                  return Stack(
                    fit: StackFit.expand,
                    children: [
                      if (remaining > 0)
                        AvatarOverview(
                          position: 0,
                          remaining: remaining,
                          counter: _counter,
                        ),
                      if (remaining > 1)
                        AvatarOverview(
                          position: 1,
                          remaining: remaining,
                          counter: _counter,
                        ),
                      if (remaining > 2)
                        AvatarOverview(
                          position: 2,
                          remaining: remaining,
                          counter: _counter,
                        ),
                      if (remaining > 3)
                        AvatarOverview(
                          position: 3,
                          remaining: remaining,
                          counter: _counter,
                        ),
                      Positioned.fill(
                        child: Center(
                          child: FractionallySizedBox(
                            alignment: Alignment.center,
                            widthFactor: 0.5,
                            heightFactor: 0.5,
                            child: FittedBox(
                              child: AvatarWidget(
                                text: '+$remaining',
                                color: Colors.black.withOpacity(0.9),
                              ),
                            ),
                          ),
                        ),
                      ),
                    ],
                  );
                },
              ),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

class AvatarOverview extends StatelessWidget {
  AvatarOverview({
    Key key,
    @required int remaining,
    @required int position,
    @required int counter,
  })  : index = counter - remaining + position,
        alignment = _getAlignment(position),
        super(key: key);

  final int index;
  final Alignment alignment;

  @override
  Widget build(BuildContext context) {
    final Avatar avatar = avatars[index];
    return FractionallySizedBox(
      key: ValueKey(index),
      alignment: alignment,
      widthFactor: 0.5,
      heightFactor: 0.5,
      child: FittedBox(
        child: AvatarWidget(
          text: avatar.initials,
          color: avatar.color,
        ),
      ),
    );
  }

  static Alignment _getAlignment(int position) {
    switch (position) {
      case 0:
        return Alignment.topLeft;
      case 1:
        return Alignment.topRight;
      case 2:
        return Alignment.bottomLeft;
      default:
        return Alignment.bottomRight;
    }
  }
}

class AvatarWidget extends StatelessWidget {
  const AvatarWidget({
    Key key,
    this.text,
    this.color,
  }) : super(key: key);

  final String text;
  final Color color;

  @override
  Widget build(BuildContext context) {
    return CircleAvatar(
      radius: 40,
      backgroundColor: color,
      foregroundColor: Colors.white,
      child: Text(
        text,
        style: TextStyle(fontSize: 30),
      ),
    );
  }
}