Custom widget as Flutter mobile app keyboard

In Flutter, you can create a widget that mimics the behavior of a keyboard using a combination of Flutter’s built-in widgets and user input handling. To create a custom widget that behaves like a keyboard, you’ll typically use GestureDetector to capture user input and modify the state of your widget accordingly.

The steps to create a simple custom keyboard widget in Flutter

• Create a Custom Keyboard Widget Class: Define a custom widget class
  that represents your keyboard. This class will extend StatefulWidget.
  The state of the widget will hold the current keyboard input.

  Design Your Keyboard UI: Within the build method of your widget,
  design the UI of your keyboard using Flutter widgets like Container,
  Row, Column, and FlatButton. Each button on the keyboard can be a
  FlatButton or a GestureDetector that responds to user input.

  Handle User Input: Wrap each button or key with a GestureDetector to
  capture taps or gestures. In the gesture handler, update the keyboard
  input state (e.g., append characters to the input string).

  Display the Keyboard: Add your custom keyboard widget to the Flutter
  UI where you want the keyboard to appear. Typically, this is within a
  Stack or a Positioned widget to overlay it on top of your input
  fields.

  Interact with Input Fields: For input fields that should use your
  custom keyboard, you can set up controllers or handlers to insert
  text from the custom keyboard into those fields when keys are
  pressed.

examples

import 'package:flutter/material.dart';

class CustomKeyboard extends StatefulWidget {
  @override
  _CustomKeyboardState createState() => _CustomKeyboardState();
}

class _CustomKeyboardState extends State<CustomKeyboard> {
  String inputText = '';

  void _handleKeyTap(String key) {
    setState(() {
      inputText += key;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        // Input field where you want to display the text
        TextField(
          controller: TextEditingController(text: inputText),
        ),
        // Custom keyboard UI
        Row(
          children: [
            GestureDetector(
              onTap: () => _handleKeyTap('1'),
              child: Container(
                // Customize your key appearance here
                child: Text('1'),
              ),
            ),
            GestureDetector(
              onTap: () => _handleKeyTap('2'),
              child: Container(
                // Customize your key appearance here
                child: Text('2'),
              ),
            ),
            // Add more keys as needed
          ],
        ),
      ],
    );
  }
}

void main() => runApp(MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Custom Keyboard Example'),
        ),
        body: CustomKeyboard(),
      ),
    ));