Keyboard Detection

This plugin gives you an easy way to detect if the keyboard is visible or not. It uses the resizing of the bottom view inset to check the the keyboard visibility, so it's native to flutter.

Introduction

Simple Usage

You just need to wrap the Scaffold with KeyboardDetection like below and listen to onChanged value.

@override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: KeyboardDetection(
        controller: KeyboardDetectionController(
          onChanged: (value) {
            print('Keyboard visibility onChanged: $value');
            setState(() {
              keyboardState = value;
              stateAsBool = keyboardDetectionController.stateAsBool();
              stateAsBoolWithParamTrue =
                  keyboardDetectionController.stateAsBool(true);
            });
          },
        ),
       child: Scaffold(
          appBar: AppBar(
            title: const Text('Keyboard Detection'),
          ),
          body: Center(
            child: Column(
              children: [
                Text('State: $keyboardState'),
                Text(
                    'State as bool (includeTransitionalState = false): $stateAsBool'),
                Text(
                    'State as bool (includeTransitionalState = true): $stateAsBoolWithParamTrue'),
                const TextField(),
              ],
            ),
          ),
        ),
      ),
    );
  }

onChanged will be returned in enum KeyboardState (unknown: unknown, visibling: visibling, visible: visible, hiding: hiding, hidden: hidden).

Usage With Controller

You can declare the controller outside the build method like below:

late KeyboardDetectionController keyboardDetectionController;

@override
void initState() {
  keyboardDetectionController = KeyboardDetectionController(
    onChanged: (value) {
      print('Keyboard visibility onChanged: $value');
      setState(() {
        keyboardState = value;
        stateAsBool = keyboardDetectionController.stateAsBool();
        stateAsBoolWithParamTrue =
                  keyboardDetectionController.stateAsBool(true);
      });
    },
  );

  // Listen to the stream
  _sub = keyboardDetectionController.stream.listen((state) {
    print('Listen to onChanged with Stream: $state');
  });

  // One time callback
  keyboardDetectionController.addCallback((state) {
    print('Listen to onChanged with one time Callback: $state');

    // End this callback by returning false
    return false;
  });

  // Looped callback
  keyboardDetectionController.addCallback((state) {
    print('Listen to onChanged with looped Callback: $state');

    // This callback will be looped
    return true;
  });

  // Looped with future callback
  keyboardDetectionController.addCallback((state) async {
    await Future.delayed(const Duration(milliseconds: 100));
    print('Listen to onChanged with looped future Callback: $state');

    // This callback will be looped
    return true;
  });

  super.initState();
}

and add it to controller inside build method:

@override
Widget build(BuildContext context) {
  return KeyboardDetection(
    controller: keyboardDetectionController,
    child: Scaffold(
      appBar: AppBar(
        title: const Text('Keyboard Detection'),
      ),
      body: Center(
        child: Padding(
          padding: const EdgeInsets.all(12.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text('State: $keyboardState'),
              Text('State as bool (includeTransitionalState = false): $stateAsBool'),
              Text('State as bool (includeTransitionalState = true): $stateAsBoolWithParamTrue'),
              FutureBuilder(
                future: keyboardDetectionController.ensureKeyboardSizeLoaded,
                builder: (context, snapshot) {
                  if (snapshot.hasData) {
                    return Text(
                        'Keyboard size is loaded with size: ${keyboardDetectionController.keyboardSize}');
                  }

                  return const Text('Keyboard size is still loading');
                },
              ),
              const TextField(),
              ElevatedButton(
                onPressed: () {
                  Navigator.push(
                    context,
                    MaterialPageRoute(
                      builder: (_) => const MyApp(),
                    ),
                  );
                },
                child: const Text('Navigate to another page'),
              ),
              ElevatedButton(
                onPressed: () {
                  Navigator.pushAndRemoveUntil(
                      context,
                      MaterialPageRoute(
                        builder: (_) => const MyApp(),
                      ),
                      (_) => false);
                },
                child: const Text('Move to another page'),
              )
            ],
          ),
        ),
      ),
    ),
  );
}

You can get the current state of the keyboard visibility by using:

• keyboardDetectionController.state: the current state of the keyboard visibility return in enum KeyboardState (unknown: unknown, visibling: visibling, visible: visible, hiding: hiding, hidden: hidden).

• keyboardDetectionController.stateAsBool([bool includeTransitionalState = false]): the current state of the keyboard visibility return in bool? (null: unknown, true: visible, false: hidden). If the includeTransitionalState is true than it will return true even when the state is visibling and false when it's hiding.

• keyboardDetectionController.addCallback(callback) to add a callback to be called when the keyboard state is changed. If the callback returns true then it will be called eachtime the keyboard is changed, if false then it will be ignored. This callback also supports the Future method.

• keyboardDetectionController.stream to listen for keyboard visibility changing events in KeyboardState.

• keyboardDetectionController.size to get the keyboard size. Please notice that this value may returns 0 even when the keyboard state is visible because the keyboard needs time to show up completely. So that, you should call keyboardDetectionController.isSizeLoaded to checks that the keyboard size is loaded or not. From version 0.5.0, you can wait for this value by using await keyboardDetectionController.ensureSizeLoaded.

Limitations

• This package uses the bottom inset to detect the keyboard visibility so it doesn't work with the floating keyboard (Issue: #1)