import 'package:flutter/material.dart';

typedef TapSearchCallback = void Function(String text); 
typedef FocusSearchCallback = void Function(bool bFocus);

class InterviewSearchBarWidget extends StatefulWidget {
  final double height;
  final Color backgroundColor;
  final Color hintColor;
  final Color color;
  final TapSearchCallback onTap;
  final FocusSearchCallback onFocusCallback;
  final EdgeInsets padding;
  final EdgeInsets margin;

  InterviewSearchBarWidget({
    Key key,
    this.height,
    this.backgroundColor,
    this.hintColor,
    this.color,
    this.onTap,
    this.onFocusCallback,
    this.padding,
    this.margin,
  }) : super(key: key);

  TextField searchTextField;


  _InterviewSearchBarWidgetState createState() => _InterviewSearchBarWidgetState();
}

class _InterviewSearchBarWidgetState extends State<InterviewSearchBarWidget> {
  TextEditingController controller = new TextEditingController();
  FocusNode focusNode = FocusNode();
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    widget.searchTextField = new TextField(
      controller: controller,
      focusNode: focusNode,
      decoration: new InputDecoration(
        hintText: "BxgStrings.search_interview_hint",
          border: InputBorder.none,
          // fillColor: Colors.red,
        //   filled: true,
        // prefixIcon: Icons.search,
        //Icon(Icons.search),
        contentPadding: EdgeInsets.fromLTRB(0.0, 2.0, 0.0, 0.0)
        // 
      ),
      onSubmitted: onSearchSubmited,
      // maxLength:40,
    );

    widget.searchTextField.focusNode.addListener(() {
      print("searchTextField=${focusNode.hasFocus}");
      if (widget.onFocusCallback != null) {
        widget.onFocusCallback(focusNode.hasFocus);
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 27,
      child: Card(
        margin: EdgeInsets.all(0),
        color: widget.backgroundColor,
        child: widget.searchTextField,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(13.5)),

      ),
    );
  }

  onSearchSubmited(String text) async {
    if (widget.onTap != null) {
      widget.onTap(text);
    }
    print("searchText = $text");
  }
}
`
`///main.dart
import 'package:flutter/material.dart';
import 'package:search_bar/interview_search_bar_widget.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,
      ),
      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> {
  int _counter = 0;
  //  FocusNode _focusNode = FocusNode();

  InterviewSearchBarWidget searchBarWidget;
  bool _bFocus = true;
  @override
  void initState() {
    // TODO: implement initState

    searchBarWidget = InterviewSearchBarWidget(
      // focusNode: _focusNode,
      backgroundColor: Colors.green,
      onFocusCallback: (bool bFocus){
        this._bFocus = bFocus;
        print("onFocusCallback--${this._bFocus}");
        setState(() { });
      },
    );

    super.initState();
  }

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @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: Column(
          // Column is also layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.start,
          children: this._bFocus
              ? <Widget>[
                  searchBarWidget,
                  Wrap(children: <Widget>[
                    FlatButton(
                      child: Text("button1"),
                      onPressed: () {
                        searchBarWidget.searchTextField.controller.text =
                            "button01";
                        searchBarWidget.searchTextField.focusNode.unfocus();
                        this._bFocus = false;
                        setState(() {});
                      },
                    ),
                    FlatButton(
                      child: Text("button2"),
                      onPressed: () {
                        searchBarWidget.searchTextField.controller.text =
                            "button02";
                        searchBarWidget.searchTextField.focusNode.unfocus();
                        this._bFocus = false;
                        setState(() {});
                      },
                    ),
                    FlatButton(
                      child: Text("button3"),
                      onPressed: () {
                        searchBarWidget.searchTextField.controller.text =
                            "button03";
                        this._bFocus = false;
                        searchBarWidget.searchTextField.focusNode.unfocus();
                        setState(() {});
                      },
                    ),
                  ]),
                ]
              : <Widget>[
                  searchBarWidget,
                  Text("content"),
                ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}