Flutter制作自己的第一个全平台APP学习之Lists篇

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摘要

伯衡君发现总结了有关flutter编程语言以制作全平台的App，通过前一篇梳理Widgets组件和Layouts布局内容，感到思路清晰了不少，这一篇文章继续进行梳理，有关Lists的内容，这个简单来说就是各种行的不同形式，伯衡君希望进行梳理后，有一个整体的认知，让我们开始吧……
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Flutter制作自己的第一个全平台APP学习之Lists篇

开篇寄语

伯衡君发现总结了有关flutter编程语言以制作全平台的App，通过前一篇梳理Widgets组件和Layouts布局内容，感到思路清晰了不少，这一篇文章继续进行梳理，有关Lists的内容，这个简单来说就是各种行的不同形式，伯衡君希望进行梳理后，有一个整体的认知，让我们开始吧。

前情提要

内容详情

以下内容大多是更改lib下的main.dart文件内容，删掉里面的内容，复制粘贴代码，开启调试就可以出现了。

ListTile

  • 单个固定高度的行，通常包含一些文本以及前导或尾部图标，试举一例如下：
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root
  // of your application
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Insert Image Demo'),
        ),
        body: Column(children: <Widget>[
          Card(child: ListTile(title: Text('Hello World!'))),
          Card(child: ListTile(title: Text('Hello World!!'))),
          Card(child: ListTile(title: Text('Hello World!!!'))),
        ]),
      ),
    );
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇

ListView.builder

  • 简单来说就是批量构建行的函数，试举例如下：
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  List<String> litems = [
    "1",
    "2",
    "Third",
    "4",
    "a",
    "b",
    "c",
    "d",
    "22",
    "111"
  ];
  // This widget is the root
  // of your application
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Insert Image Demo'),
        ),
        body: new ListView.builder(
            itemCount: 10,
            itemBuilder: (BuildContext ctxt, int index) {
              return new Card(
                child: Text(litems[index]));
            }),
      ),
    );
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇

GridList

  • 想必大家对于相册并不陌生，这个类就相当于相册的展现形式，试举例如下：
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  List<String> litems = [
    "1",
    "2",
    "Third",
    "4",
    "a",
    "b",
    "c",
    "d",
    "22",
    "111"
  ];
  // This widget is the root
  // of your application
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Insert Image Demo'),
        ),
        body: GridView.count(
          // Create a grid with 2 columns. If you change the scrollDirection to
          // horizontal, this produces 2 rows.
          crossAxisCount: 2,
          // Generate 100 widgets that display their index in the List.
          children: List.generate(100, (index) {
            return Center(
              child: Container(
                decoration: BoxDecoration(
                  border: Border.all(color: Colors.grey, width: 3.0),
                ),
                padding: const EdgeInsets.all(16.0),
                child: Text(
                  'Item $index',
                  style: Theme.of(context).textTheme.headline5,
                ),
              ),
            );
          }),
        ),
      ),
    );
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇

ExpansionTile

  • 这个是点击后展开隐藏内容，相当于Web中点击后出现列表<li></li>这样，试举例如下，首先是在main.dart内输入以下代码：
import 'package:flutter/material.dart';
import 'home.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Expansion View',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Home(),
    );
  }
}

接着在main.dart文件的文件夹下新建home.dart文件，输入以下代码：

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

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          'Flutter Expansion View',
        ),
        centerTitle: true,
        elevation: 0.0,
      ),
      body: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 30.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Row(
              children: <Widget>[
                Expanded(
                  child: TextButton(
                    onPressed: () {
                      Navigator.push(
                          context,
                          MaterialPageRoute(
                              builder: (BuildContext context) =>
                                  Expansiontile()));
                    },
                    child: Text('ExpansionTile'),
                  ),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

接着还是在文件夹下，新建一个名为expantionTile.dart文件，输入以下代码：

import 'package:flutter/material.dart';

class Expansiontile extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: Text('Expansion Tile'),
      ),
      body: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 30.0),
        child: Column(
          children: <Widget>[
            SizedBox(height: 20.0),
            ExpansionTile(
              title: Text(
                "Title",
                style: TextStyle(fontSize: 18.0, fontWeight: FontWeight.bold),
              ),
              children: <Widget>[
                ExpansionTile(
                  title: Text(
                    'Sub title',
                  ),
                  children: <Widget>[
                    ListTile(
                      title: Text('data'),
                    )
                  ],
                ),
                ListTile(
                  title: Text('data'),
                )
              ],
            ),
          ],
        ),
      ),
    );
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇

Swipe to Dismiss

  • 左右滑动，删除掉该行，这种方式很常见以在构建App，试举例如下：
import 'package:flutter/material.dart';

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

// ignore: must_be_immutable
class MyApp extends StatelessWidget {
  List<String> items = [
    "1",
    "2",
    "Third",
    "4",
    "a",
    "b",
    "c",
    "d",
    "22",
    "111"
  ];
  // This widget is the root
  // of your application
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
      appBar: AppBar(
        title: Text('Insert Image Demo'),
      ),
      body: ListView.builder(
          itemCount: items.length,
          itemBuilder: (context, index) {
            final item = items[index];
            return Dismissible(
              // Each Dismissible must contain a Key. Keys allow Flutter to
              // uniquely identify widgets.
              key: Key(item),
              // Provide a function that tells the app
              // what to do after an item has been swiped away.
              onDismissed: (direction) {
                // Remove the item from the data source.
                items.removeAt(index);

                // Then show a snackbar.
                ScaffoldMessenger.of(context)
                    .showSnackBar(SnackBar(content: Text('$item dismissed')));
              },
              // Show a red background as the item is swiped away.
              background: Container(color: Colors.red),
              child: ListTile(title: Text('$item')),
            );
          }),
    ));
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇

DataTable

  • 这个是新建一个交互式或者非交互式的表格，展现更多的信息，试举例如下：
import 'package:flutter/material.dart';

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

/// This is the main application widget.
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const MyStatelessWidget(),
      ),
    );
  }
}

/// This is the stateless widget that the main application instantiates.
class MyStatelessWidget extends StatelessWidget {
  const MyStatelessWidget({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return DataTable(
      columns: const <DataColumn>[
        DataColumn(
          label: Text(
            'Name',
            style: TextStyle(fontStyle: FontStyle.italic),
          ),
        ),
        DataColumn(
          label: Text(
            'Age',
            style: TextStyle(fontStyle: FontStyle.italic),
          ),
        ),
        DataColumn(
          label: Text(
            'Role',
            style: TextStyle(fontStyle: FontStyle.italic),
          ),
        ),
        DataColumn(
          label: Text(
            'Ranking',
            style: TextStyle(fontStyle: FontStyle.italic),
          ),
        ),
      ],
      rows: const <DataRow>[
        DataRow(
          cells: <DataCell>[
            DataCell(Text('MM')),
            DataCell(Text('20')),
            DataCell(Text('girl')),
            DataCell(Text('98')),
          ],
        ),
        DataRow(
          cells: <DataCell>[
            DataCell(Text('MM')),
            DataCell(Text('20')),
            DataCell(Text('girl')),
            DataCell(Text('98')),
          ],
        ),
        DataRow(
          cells: <DataCell>[
            DataCell(Text('MM')),
            DataCell(Text('20')),
            DataCell(Text('girl')),
            DataCell(Text('98')),
          ],
        ),
        DataRow(
          cells: <DataCell>[
            DataCell(Text('MM')),
            DataCell(Text('20')),
            DataCell(Text('girl')),
            DataCell(Text('98')),
          ],
        ),
      ],
    );
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇

ReorderableListView

  • 用户可以进行自定义排序的一个类，在App中很常见，试举例如下：
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // Remove the debug banner
      debugShowCheckedModeBanner: false,
      title: 'Kindacode.com',
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  // Generate dummy data for the list view
  List<String> _products =
      List.generate(100, (index) => "Product ${index.toString()}");

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Reorder Demo'),
      ),
      body: ReorderableListView.builder(
          itemCount: _products.length,
          itemBuilder: (context, index) {
            final String productName = _products[index];
            return Card(
              key: ValueKey(productName),
              color: Colors.amberAccent,
              elevation: 1,
              margin: const EdgeInsets.all(10),
              child: ListTile(
                contentPadding: EdgeInsets.all(30),
                title: Text(
                  productName,
                  style: TextStyle(fontSize: 18),
                ),
                onTap: () {/* Do something else */},
              ),
            );
          },
          // The reorder function
          onReorder: (oldIndex, newIndex) {
            setState(() {
              if (newIndex > oldIndex) {
                newIndex = newIndex - 1;
              }
              final element = _products.removeAt(oldIndex);
              _products.insert(newIndex, element);
            });
          }),
    );
  }
}
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // Remove the debug banner
      debugShowCheckedModeBanner: false,
      title: 'Kindacode.com',
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  // Generate dummy data for the list view
  List<String> _products =
      List.generate(100, (index) => "Product ${index.toString()}");

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Reorder Demo'),
      ),
      body: ReorderableListView.builder(
          itemCount: _products.length,
          itemBuilder: (context, index) {
            final String productName = _products[index];
            return Card(
              key: ValueKey(productName),
              color: Colors.amberAccent,
              elevation: 1,
              margin: const EdgeInsets.all(10),
              child: ListTile(
                contentPadding: EdgeInsets.all(30),
                title: Text(
                  productName,
                  style: TextStyle(fontSize: 18),
                ),
                onTap: () {/* Do something else */},
              ),
            );
          },
          // The reorder function
          onReorder: (oldIndex, newIndex) {
            setState(() {
              if (newIndex > oldIndex) {
                newIndex = newIndex - 1;
              }
              final element = _products.removeAt(oldIndex);
              _products.insert(newIndex, element);
            });
          }),
    );
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇

Slidable list tile

  • 这个类似于dismiss，左右滑动，但不是消除，而是出现选项，比如常用的邮箱App，标记已读或者删除等活动行为，就可以用此方法，试举一例：

首先是在pubspec.yaml这个文件添加支持的库，如下所示：

dependencies:
  flutter:
    sdk: flutter
  flutter_slidable: ^0.6.0

之后就可以在main.dart文件中调用了，代码如下：

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

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    final List<String> items =
        new List<String>.generate(10, (i) => "item  ${i + 1}");
    return Scaffold(
      appBar: AppBar(
        title: Text("Flutter Slideable Example"),
      ),
      body: ListView.separated(
          separatorBuilder: (context, index) => Divider(
                color: Colors.black,
              ),
          itemCount: items.length,
          itemBuilder: (context, int index) {
            return Slidable(
              actions: <Widget>[
                IconSlideAction(
                    icon: Icons.more,
                    caption: 'MORE',
                    color: Colors.blue,
                    onTap: () {
                      print("More ${items[index]} is Clicked");
                    }),
              ],
              secondaryActions: <Widget>[
                IconSlideAction(
                    icon: Icons.clear,
                    color: Colors.red,
                    caption: 'Cancel',
                    onTap: () {
                      print("Cancel ${items[index]} is Clicked");
                    })
              ],
              child: ListTile(
                leading: Icon(Icons.message),
                title: Text("${items[index]}"),
                subtitle: Text("Slide left or right"),
                trailing: Icon(Icons.arrow_back),
              ),
              actionPane: SlidableDrawerActionPane(),
            );
          }),
    );
  }
}

生成效果如下图所示：

Flutter制作自己的第一个全平台APP学习之Lists篇
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