keyboard open check

check_keyboard.dart

import 'dart:async';

import 'package:flutter/material.dart';

void main() {
  runApp(const CheckKeyBoard());
}

class CheckKeyBoard extends StatelessWidget {
  const CheckKeyBoard({Key? key}) : super(key: key);

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

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

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final key = const KeyboardCheck();
  var focusNode = FocusNode();

  @override
  void initState() {
    super.initState();
    focusNode.addListener(() {
      if (!focusNode.hasFocus) key.close();
    });
  }

  @override
  Widget build(BuildContext context) {
    if (focusNode.hasFocus) {
      key.check(MediaQuery.of(context).viewInsets.bottom);
    }
    return Scaffold(
      appBar: AppBar(
        title: key,
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            TextField(
              focusNode: focusNode,
              onTap: () => FocusScope.of(context).requestFocus(focusNode),
            ),
          ],
        ),
      ),
    );
  }
}

class KeyboardCheck extends StatelessWidget {
  const KeyboardCheck({Key? key}) : super(key: key);
  static var streamController = StreamController<String?>();

  void close() {
    streamController.sink.add(null);
  }

  void check(double keyboardHeight) {
    var counter = 0;
    while (counter < keyboardHeight) {
      counter += 1;
      if (counter == keyboardHeight) {
        streamController.sink.add('Keyboard Open');
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return StreamBuilder(
      stream: streamController.stream,
      builder: (
        BuildContext context,
        AsyncSnapshot<String?> snapShot,
      ) {
        if (snapShot.data?.isNotEmpty ?? false) {
          return Text(
            snapShot.data ?? '',
            style: const TextStyle(color: Colors.black),
          );
        } else {
          return const Text(
            'Keyboard Close',
            style: TextStyle(color: Colors.white),
          );
        }
      },
    );
  }
}

2022-06-09.6.15.37.mov