Flutter可扩展底部导航栏插件expandable_bottom_bar的使用

ExpandableBottomAppBar

Animatable bottom app bar with expandable sheet

预览

开始使用

在 pubspec.yaml 文件中添加依赖：

dependencies:
  ...
  expandable_bottom_bar: any

基本用法

在你的代码中添加 BottomExpandableAppBar 小部件：

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

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

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

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

  final String title;

  [@override](/user/override)
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final BottomAppBarController bbc = BottomAppBarController();

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '0',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      bottomNavigationBar: BottomExpandableAppBar(
        controller: bbc,
        expandedHeight: 200.0,
        horizontalMargin: 16,
        expandedBackColor: Theme.of(context).backgroundColor,
        expandedBody: Center(
          child: Text("Hello world!"),
        ),
        bottomAppBarBody: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Row(
            mainAxisSize: MainAxisSize.max,
            children: <Widget>[
              Expanded(
                child: Text(
                  "Hello",
                  textAlign: TextAlign.center,
                ),
              ),
              Spacer(
                flex: 2,
              ),
              Expanded(
                child: Text(
                  "World",
                  textAlign: TextAlign.center,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

自定义（可选）

BottomExpandableAppBar

• horizontalMargin - 从边缘到表格侧面的距离

• bottomOffset - 关闭状态下顶部表格边缘与顶部应用程序栏边缘之间的距离

• shape - FAB 的缺口形状

• appBarHeight - 如果你需要更改应用程序栏的高度

• bottomAppBarColor - 应用程序栏容器的背景颜色 或

• appBarDecoration - 应用程序栏容器的装饰

• expandedBackColor - 表格容器的背景颜色 或

• expandedDecoration - 表格容器的装饰

BottomAppBarController

设置

• snap - 如果为真，则表格将快速切换到打开和关闭状态
• dragLength - 指针需要移动的距离以完全打开或关闭表格

回调

• onDrag - 使用它与 GestureDetector 进行滑动控制

• onDragEnd - 使用它与 GestureDetector 进行滑动控制

• open - 切换表格到关闭状态

• close - 切换表格到打开状态

• swap - 如果表格是打开的，则关闭表格，反之亦然

完整示例

以下是一个完整的示例代码，展示了如何使用 BottomExpandableAppBar 和 BottomAppBarController：

import 'package:example/theme.dart';
import 'package:expandable_bottom_bar/expandable_bottom_bar.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: CustomTheme.dark(),
      home: DefaultBottomBarController(
        child: ExamplePage(),
      ),
    );
  }
}

class ExamplePage extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Theme.of(context).canvasColor,
      //
      // 设置 [extendBody] 以便底部应用程序栏重叠页面内容
      extendBody: true,
      appBar: AppBar(
        title: Text("Panel Showcase"),
        backgroundColor: Theme.of(context).bottomAppBarColor,
      ),
      //
      // 使用停靠的 FAB 来处理表格的状态
      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
      floatingActionButton: GestureDetector(
        //
        // 设置 onVerticalDrag 事件以拖动手势控制器进行滑动效果
        onVerticalDragUpdate: DefaultBottomBarController.of(context).onDrag,
        onVerticalDragEnd: DefaultBottomBarController.of(context).onDragEnd,
        child: FloatingActionButton.extended(
          label: AnimatedBuilder(
            animation: DefaultBottomBarController.of(context).state,
            builder: (context, child) => Row(
              children: [
                Text(
                  DefaultBottomBarController.of(context).isOpen
                      ? "Pull"
                      : "Pull",
                ),
                const SizedBox(width: 4.0),
                AnimatedBuilder(
                  animation: DefaultBottomBarController.of(context).state,
                  builder: (context, child) => Transform(
                    alignment: Alignment.center,
                    transform: Matrix4.diagonal3Values(
                      1,
                      DefaultBottomBarController.of(context).state.value * 2 -
                          1,
                      1,
                    ),
                    child: child,
                  ),
                  child: RotatedBox(
                    quarterTurns: 1,
                    child: Icon(
                      Icons.chevron_right,
                      size: 20,
                    ),
                  ),
                ),
              ],
            ),
          ),
          elevation: 2,
          backgroundColor: Colors.deepOrange,
          foregroundColor: Colors.white,
          //
          // 设置 onPressed 事件以切换底部栏的状态
          onPressed: () => DefaultBottomBarController.of(context).swap(),
        ),
      ),
      //
      // 实际的可扩展底部栏
      bottomNavigationBar: BottomExpandableAppBar(
        horizontalMargin: 16,
        shape: AutomaticNotchedShape(
            RoundedRectangleBorder(), StadiumBorder(side: BorderSide())),
        expandedBackColor: Theme.of(context).backgroundColor,
        expandedBody: Center(
          child: Text("Hello world!"),
        ),
        bottomAppBarBody: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Row(
            mainAxisSize: MainAxisSize.max,
            children: <Widget>[
              Expanded(
                child: Text(
                  "Foo",
                  textAlign: TextAlign.center,
                ),
              ),
              Spacer(
                flex: 2,
              ),
              Expanded(
                child: Text(
                  "Bar",
                  textAlign: TextAlign.center,
                ),
              ),
            ],
          ),
        ),
      ),
      body: GridView.builder(
        itemCount: 30,
        gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 2,
        ),
        itemBuilder: (context, index) => Card(
          color: Theme.of(context).bottomAppBarColor,
          child: Text(
            index.toString(),
          ),
        ),
      ),
    );
  }
}