DismissableApp

import 'package:flutter/material.dart';

class DismissableApp extends StatefulWidget {
  @override
  _DismissableAppState createState() => _DismissableAppState();
}

class _DismissableAppState extends State<DismissableApp> {
  List _trips = List<Trip>();

  @override
  void initState() {
    _trips
      ..add(Trip(id: 0, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 1, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 2, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 3, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 4, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 5, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 6, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 7, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 8, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 9, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 10, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 11, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 12, tripName: 'Rome', tripLocation: 'Italy'))
      ..add(Trip(id: 13, tripName: 'Rome', tripLocation: 'Italy'));

    super.initState();
  }

  void _markTripCompleted() {
    //mark trip completed in database or web service
    print('Completed');
  }

  void _deleteTrip() {
    //Delete trip from database or web service
    print('deleted');
  }

  ListTile _buildListTile(int index) {
    return ListTile(
      title: Text('${_trips[index].tripName}'),
      subtitle: Text('${_trips[index].tripLocation}'),
      leading: Icon(Icons.flight),
      trailing: Icon(Icons.fastfood),
    );
  }

  Container _buildCompleteTrip() {
    return Container(
      color: Colors.green,
      child: Padding(
        padding: EdgeInsets.all(16.0),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.start,
          children: [
            Icon(
              Icons.done,
              color: Colors.white,
            )
          ],
        ),
      ),
    );
  }

  Container _buildRemoveTrip() {
    return Container(
      color: Colors.red,
      child: Padding(
        padding: EdgeInsets.all(16.0),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.end,
          children: [
            Icon(
              Icons.delete,
              color: Colors.white,
            )
          ],
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: ListView.builder(
          itemCount: _trips.length,
          itemBuilder: (context, index) {
            return Dismissible(
              key: Key(_trips[index].id.toString()),
              child: _buildListTile(index),
              background: _buildCompleteTrip(),
              secondaryBackground: _buildRemoveTrip(),
              onDismissed: (DismissDirection direction) {
                direction == DismissDirection.startToEnd
                    ? _markTripCompleted()
                    : _deleteTrip();
                setState(() {
                  _trips.removeAt(index);
                });
              },
            );
          }),
    );
  }
}

class Trip {
  int id;
  String tripName;
  String tripLocation;

  Trip({this.id, this.tripName, this.tripLocation});
}