flutter/examples/flutter_gallery/lib/demo/cupertino/cupertino_refresh_demo.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';
import 'dart:math' show Random;

import 'package:flutter/cupertino.dart';

import '../../gallery/demo.dart';

class CupertinoRefreshControlDemo extends StatefulWidget {
  static const String routeName = '/cupertino/refresh';

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

class _CupertinoRefreshControlDemoState extends State<CupertinoRefreshControlDemo> {
  List<List<String>> randomizedContacts;

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

  void repopulateList() {
    final Random random = Random();
    randomizedContacts = List<List<String>>.generate(
      100,
      (int index) {
        return contacts[random.nextInt(contacts.length)]
            // Randomly adds a telephone icon next to the contact or not.
            ..add(random.nextBool().toString());
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return DefaultTextStyle(
      style: CupertinoTheme.of(context).textTheme.textStyle,
      child: CupertinoPageScaffold(
        backgroundColor: CupertinoColors.systemGroupedBackground,
        child: CustomScrollView(
          // If left unspecified, the [CustomScrollView] appends an
          // [AlwaysScrollableScrollPhysics]. Behind the scene, the ScrollableState
          // will attach that [AlwaysScrollableScrollPhysics] to the output of
          // [ScrollConfiguration.of] which will be a [ClampingScrollPhysics]
          // on Android.
          // To demonstrate the iOS behavior in this demo and to ensure that the list
          // always scrolls, we specifically use a [BouncingScrollPhysics] combined
          // with a [AlwaysScrollableScrollPhysics]
          physics: const BouncingScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
          slivers: <Widget>[
            CupertinoSliverNavigationBar(
              largeTitle: const Text('Refresh'),
              // We're specifying a back label here because the previous page
              // is a Material page. CupertinoPageRoutes could auto-populate
              // these back labels.
              previousPageTitle: 'Cupertino',
              trailing: CupertinoDemoDocumentationButton(CupertinoRefreshControlDemo.routeName),
            ),
            CupertinoSliverRefreshControl(
              onRefresh: () {
                return Future<void>.delayed(const Duration(seconds: 2))
                ..then<void>((_) {
                    if (mounted) {
                      setState(() => repopulateList());
                    }
                });
              },
            ),
            SliverSafeArea(
              top: false, // Top safe area is consumed by the navigation bar.
              sliver: SliverList(
                delegate: SliverChildBuilderDelegate(
                  (BuildContext context, int index) {
                    return _ListItem(
                      name: randomizedContacts[index][0],
                      place: randomizedContacts[index][1],
                      date: randomizedContacts[index][2],
                      called: randomizedContacts[index][3] == 'true',
                    );
                  },
                  childCount: 20,
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

List<List<String>> contacts = <List<String>>[
  <String>['George Washington', 'Westmoreland County', ' 4/30/1789'],
  <String>['John Adams', 'Braintree', ' 3/4/1797'],
  <String>['Thomas Jefferson', 'Shadwell', ' 3/4/1801'],
  <String>['James Madison', 'Port Conway', ' 3/4/1809'],
  <String>['James Monroe', 'Monroe Hall', ' 3/4/1817'],
  <String>['Andrew Jackson', 'Waxhaws Region South/North', ' 3/4/1829'],
  <String>['John Quincy Adams', 'Braintree', ' 3/4/1825'],
  <String>['William Henry Harrison', 'Charles City County', ' 3/4/1841'],
  <String>['Martin Van Buren', 'Kinderhook New', ' 3/4/1837'],
  <String>['Zachary Taylor', 'Barboursville', ' 3/4/1849'],
  <String>['John Tyler', 'Charles City County', ' 4/4/1841'],
  <String>['James Buchanan', 'Cove Gap', ' 3/4/1857'],
  <String>['James K. Polk', 'Pineville North', ' 3/4/1845'],
  <String>['Millard Fillmore', 'Summerhill New', '7/9/1850'],
  <String>['Franklin Pierce', 'Hillsborough New', ' 3/4/1853'],
  <String>['Andrew Johnson', 'Raleigh North', ' 4/15/1865'],
  <String>['Abraham Lincoln', 'Sinking Spring', ' 3/4/1861'],
  <String>['Ulysses S. Grant', 'Point Pleasant', ' 3/4/1869'],
  <String>['Rutherford B. Hayes', 'Delaware', ' 3/4/1877'],
  <String>['Chester A. Arthur', 'Fairfield', ' 9/19/1881'],
  <String>['James A. Garfield', 'Moreland Hills', ' 3/4/1881'],
  <String>['Benjamin Harrison', 'North Bend', ' 3/4/1889'],
  <String>['Grover Cleveland', 'Caldwell New', ' 3/4/1885'],
  <String>['William McKinley', 'Niles', ' 3/4/1897'],
  <String>['Woodrow Wilson', 'Staunton', ' 3/4/1913'],
  <String>['William H. Taft', 'Cincinnati', ' 3/4/1909'],
  <String>['Theodore Roosevelt', 'New York City New', ' 9/14/1901'],
  <String>['Warren G. Harding', 'Blooming Grove', ' 3/4/1921'],
  <String>['Calvin Coolidge', 'Plymouth', '8/2/1923'],
  <String>['Herbert Hoover', 'West Branch', ' 3/4/1929'],
  <String>['Franklin D. Roosevelt', 'Hyde Park New', ' 3/4/1933'],
  <String>['Harry S. Truman', 'Lamar', ' 4/12/1945'],
  <String>['Dwight D. Eisenhower', 'Denison', ' 1/20/1953'],
  <String>['Lyndon B. Johnson', 'Stonewall', '11/22/1963'],
  <String>['Ronald Reagan', 'Tampico', ' 1/20/1981'],
  <String>['Richard Nixon', 'Yorba Linda', ' 1/20/1969'],
  <String>['Gerald Ford', 'Omaha', 'August 9/1974'],
  <String>['John F. Kennedy', 'Brookline', ' 1/20/1961'],
  <String>['George H. W. Bush', 'Milton', ' 1/20/1989'],
  <String>['Jimmy Carter', 'Plains', ' 1/20/1977'],
  <String>['George W. Bush', 'New Haven', ' 1/20, 2001'],
  <String>['Bill Clinton', 'Hope', ' 1/20/1993'],
  <String>['Barack Obama', 'Honolulu', ' 1/20/2009'],
  <String>['Donald J. Trump', 'New York City', ' 1/20/2017'],
];

class _ListItem extends StatelessWidget {
  const _ListItem({
    this.name,
    this.place,
    this.date,
    this.called,
  });

  final String name;
  final String place;
  final String date;
  final bool called;

  @override
  Widget build(BuildContext context) {
    return Container(
      color: CupertinoDynamicColor.resolve(CupertinoColors.systemBackground, context),
      height: 60.0,
      padding: const EdgeInsets.only(top: 9.0),
      child: Row(
        children: <Widget>[
          Container(
            width: 38.0,
            child: called
                ? Align(
                    alignment: Alignment.topCenter,
                    child: Icon(
                      CupertinoIcons.phone_solid,
                      color: CupertinoColors.inactiveGray.resolveFrom(context),
                      size: 18.0,
                    ),
                  )
                : null,
          ),
        Expanded(
          child: Container(
              decoration: const BoxDecoration(
                border: Border(
                  bottom: BorderSide(color: Color(0xFFBCBBC1), width: 0.0),
                ),
              ),
              padding: const EdgeInsets.only(left: 1.0, bottom: 9.0, right: 10.0),
              child: Row(
                children: <Widget>[
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      children: <Widget>[
                        Text(
                          name,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: const TextStyle(
                            fontWeight: FontWeight.w600,
                            letterSpacing: -0.18,
                          ),
                        ),
                        Text(
                          place,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: TextStyle(
                            fontSize: 15.0,
                            letterSpacing: -0.24,
                            color: CupertinoColors.inactiveGray.resolveFrom(context),
                          ),
                        ),
                      ],
                    ),
                  ),
                  Text(
                    date,
                    style: TextStyle(
                      color: CupertinoColors.inactiveGray.resolveFrom(context),
                      fontSize: 15.0,
                      letterSpacing: -0.41,
                    ),
                  ),
                  Padding(
                    padding: const EdgeInsets.only(left: 9.0),
                    child: Icon(
                      CupertinoIcons.info,
                      color: CupertinoTheme.of(context).primaryColor,
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}