How to Temporarily Disable Keyboard Input in a macOS Application?

Question

I am working on a macOS application using Swift and Flutter, and I need to create a functionality to temporarily disable the keyboard input, similar to a "keyboard clean tool". I have attempted several approaches but haven't found a viable solution yet.

import Cocoa
import FlutterMacOS

class KeyboardServicePlugin: NSObject, FlutterPlugin {
    private var isBlockingKeyboard: Bool = false

    public static func register(with registrar: FlutterPluginRegistrar) {
        let channel = FlutterMethodChannel(
            name: "com.example.app/keyboard_service",
            binaryMessenger: registrar.messenger
        )
        let instance = KeyboardServicePlugin()
        registrar.addMethodCallDelegate(instance, channel: channel)
    }

    public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
        switch call.method {
            case "disableKeyboard":
                disableKeyboard()
                result(nil)
            case "enableKeyboard":
                enableKeyboard()
                result(nil)
            case "getKeyboardStatus":
                result(isBlockingKeyboard)
            case "toggleKeyboard":
                toggleKeyboard()
                result(nil)
            default:
                result(FlutterMethodNotImplemented)
        }
    }

    private func disableKeyboard() {
        // I'm not sure how to disable keyboard input in macOS
    }

    private func enableKeyboard() {
         // I'm not sure how to enable keyboard input in macOS
    }

    private func toggleKeyboard() {
        if isBlockingKeyboard {
            enableKeyboard()
        } else {
            disableKeyboard()
        }
    }
}

The solution should be able to block and unblock the keyboard input programmatically within my application.

Answer 1

you can find needed solution in this project source code:

https://github.com/pqrs-org/Karabiner-Elements

as this open-source app is also have a disable keyboard feature: