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Code Explained - The Terms List :

​import 'package:flutter/material.dart';
import '../Pages/page.dart';
import '../Pages/termslist.dart';
class Terms1 extends StatelessWidget {
  @override
  Terms1();
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Unit One Terms'),
          leading:  new IconButton(
              icon: new Icon(Icons.arrow_back),
              color: Colors.white,
              iconSize: 25.0,

              onPressed: () => Navigator.of(context).pushAndRemoveUntil(new MaterialPageRoute(builder: (BuildContext context) => new TermsList()), (Route route) => route == null)
          ),
        ),
        body: ListView.builder(
          itemBuilder: (BuildContext context, int index) =>
              EntryItem(data[index]),
          itemCount: data.length,
        ),
      ),
    );
  }
}

// One entry in the multilevel list displayed by this app.
class Entry {
  Entry(this.title, [this.children = const <Entry>[]]);

  final String title;
  final List<Entry> children;
}

// The entire multilevel list displayed by this app.
final List<Entry> data = <Entry>[
  Entry(
    'Social Contract Theory',
    <Entry>[
      Entry(
        'People give up certain rights to the government in order to be protected',
      ),
],
  ),
  Entry(
    'John Locke',
    <Entry>[
      Entry(
        'Wrote the Second Treatise on Government and established the idea of Inalienable Rights',
      ),
    ],
  ),
  Entry(
    'Inalienable Rights',
    <Entry>[
      Entry(
        'A right that according to natural law cannot be taken away, denied or transferred. These are the rights to life, liberty, and property.',
      ),
    ],
  ),
  Entry(
    'Montesquieu',
    <Entry>[
      Entry(
        'Wrote the Spirit of the Law and established the idea of Checks and Balances',
      ),
    ],
  ),
  Entry(
    'Machiavelli',
    <Entry>[
      Entry(
        'Wrote the Prince and established the idea that it is better to be feared than loved',

      ),

    ],

  ),
  Entry(
      'Thomas Hobbes',
      <Entry>[
      Entry(
      'Wrote the Leviathan and established the idea of the absolute power of the monarch by divine right',

  ),
  ],
  ),
  Entry(
    'Democracy',
    <Entry>[
      Entry(
        'A system of government by the whole population or all the eligible members of a state',

      ),
    ],
  ),
  Entry(
    'Representative Democracy',
    <Entry>[
      Entry(
        'Type of democracy in which citizens elect representatives who make up a legislature',

      ),
    ],
  ),
  Entry(
    'Minimalist Democracy',
    <Entry>[
      Entry(
        'Type of democracy in which citizens elect political teams and give them the right to rule',

      ),
    ],
  ),
  Entry(
    'Direct Democracy',
    <Entry>[
      Entry(
        'Type of democracy in which citizens cast their votes directly on laws,policies, and other legislative affairs',

      ),
    ],
  ),
  Entry(
    'Pluralism',
    <Entry>[
      Entry(
        'A theory of government that a large and diverse array of groups compete for influence leading to the weakening state of the government',

      ),
    ],
  ),
  Entry(
    'Elitism',
    <Entry>[
      Entry(
        'A theory of government that only those who have met the criteria for being elite may enter the political system',

      ),
    ],
  ),
  Entry(
    'Hyperpluralism',
    <Entry>[
      Entry(
        'Pluralism to the extreme; Overwhelming amount of groups pull at the systems of power creates a gridlock',

      ),
    ],
  ),
  Entry(
    'Collective Goods',
    <Entry>[
      Entry(
        'Goods and services that are by their nature cannot be denied to anyone',

      ),
    ],
  ),
  Entry(
    'Political Culture',
    <Entry>[
      Entry(
        'An overall set of values widely shared within a society',

      ),
    ],
  ),
  Entry(
    'Politics',
    <Entry>[
      Entry(
        'Process determining the leaders we select and the policies they pursue',

      ),
    ],
  ),
  Entry(
    'Public Policy',
    <Entry>[
      Entry(
        'A choice that government makes in response to a political issue',

      ),
    ],
  ),
  Entry(
    'Linkage Institutions',
    <Entry>[
      Entry(
        'Political Channels through which peoples concerns become political issues on the policy agenda',

      ),
    ],
  ),
  Entry(
    'New Jersey Plan',
    <Entry>[
      Entry(
        'Called for equal representation in Congress',

      ),
    ],
  ),
  Entry(
    'Virginia Plan',
    <Entry>[
      Entry(
        'Called for proportional representation in Congress',

      ),
    ],
  ),
  Entry(
    'Connecticut Compromise',
    <Entry>[
      Entry(
        'AKA The Great Compromise, combined both the Virginia and New Jersey Plan to create a bicameral legislature with equal representation for the senate and proportional representaiton for the House of Representatives',

      ),
    ],
  ),

];

// Displays one Entry. If the entry has children then it's displayed
// with an ExpansionTile.
class EntryItem extends StatelessWidget {
  const EntryItem(this.entry);

  final Entry entry;

  Widget _buildTiles(Entry root) {
    if (root.children.isEmpty) return ListTile(title: Text(root.title));
    return ExpansionTile(
      key: PageStorageKey<Entry>(root),
      title: Text(root.title),
      children: root.children.map(_buildTiles).toList(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return _buildTiles(entry);
  }
}

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