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README.md

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readme.md

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main.dart

import 'package:flutter/cupertino.dart';
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(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
        // This makes the visual density adapt to the platform that you run
        // the app on. For desktop platforms, the controls will be smaller and
        // closer together (more dense) than on mobile platforms.
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  final node = FocusScopeNode();

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: FocusScope(
          node: node,
          child: Padding(
            padding: const EdgeInsets.all(8.0),
            child: Column(
              children: <Widget>[
                TextField(),
                Row(
                  children: <Widget>[
                    Expanded(
                      child: TextField(),
                    ),
                    RaisedButton(
                      focusNode: FocusNode(canRequestFocus: false),
                      child: Text('假装我是获取验证码'),
                      onPressed: () {},
                    ),
                  ],
                ),
                TextField(),
                TextField(),
                CupertinoTextField(),
                TextField(),
                CupertinoTextField(),
              ],
            ),
          ),
        ),
      ),
      bottomSheet: Container(
        height: 50,
        child: Row(
          children: <Widget>[
            IconButton(
              icon: Icon(Icons.arrow_upward),
              onPressed: () {
                FocusNode current;
                if (node.hasFocus && node.focusedChild != null) {
                  current = node.focusedChild;
                } else {
                  return;
                }

                final canReqFocus = node.children.where((element) {
                  return element.canRequestFocus &&
                      element.context.widget is EditableText;
                }).toList();

                for (var i = 0; i < canReqFocus.length; i++) {
                  if (current == canReqFocus[i]) {
                    if (i == 0) {
                      canReqFocus[canReqFocus.length - 1].requestFocus();
                    } else {
                      canReqFocus[i - 1].requestFocus();
                    }
                    return;
                  }
                }
              },
            ),
            IconButton(
              icon: Icon(Icons.arrow_downward),
              onPressed: () {
                FocusNode current;
                if (node.hasFocus && node.focusedChild != null) {
                  current = node.focusedChild;
                } else {
                  return;
                }

                final canReqFocus = node.children.where((element) {
                  return element.canRequestFocus &&
                      element.context.widget is EditableText;
                }).toList();

                for (var i = 0; i < canReqFocus.length; i++) {
                  if (current == canReqFocus[i]) {
                    if (i == canReqFocus.length - 1) {
                      canReqFocus[0].requestFocus();
                    } else {
                      canReqFocus[i + 1].requestFocus();
                    }
                    return;
                  }
                }
              },
            ),
            Expanded(child: Container()),
            IconButton(
              icon: Icon(Icons.keyboard_hide),
              onPressed: () {
                if (node.hasFocus) {
                  node.focusedChild?.unfocus();
                }
              },
            ),
          ],
        ),
      ),
    );
  }
}