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Keyboard Detection

Easily detect keyboard visibility in your Flutter app with this plugin. It leverages the resizing of the bottom view inset to determine keyboard visibility, ensuring a native Flutter experience.

Introduction

Features

• Detect keyboard visibility changes (unknown, visibling, visible, hiding, hidden).
• Access keyboard visibility state as an enum or boolean.
• Listen to keyboard visibility changes via callbacks or streams.
• Retrieve keyboard size when it is fully loaded.

Simple Usage

Wrap your Scaffold with KeyboardDetection and listen to the onChanged value:

@override
Widget build(BuildContext context) {
  return MaterialApp(
    home: KeyboardDetection(
      controller: KeyboardDetectionController(
        onChanged: (value) {
          print('Keyboard visibility changed: $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(),
            ],
          ),
        ),
      ),
    ),
  );
}

The onChanged callback returns a KeyboardState enum (unknown, visibling, visible, hiding, hidden).

Advanced Usage with Controller

Declare the KeyboardDetectionController outside the build method for more control:

late KeyboardDetectionController keyboardDetectionController;

@override
void initState() {
  keyboardDetectionController = KeyboardDetectionController(
    onChanged: (value) {
      print('Keyboard visibility changed: $value');
      keyboardState = value;
    },
  );

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

  // Add one-time callback
  keyboardDetectionController.addCallback((state) {
    print('One-time callback: $state');
    return false;
  });

  // Add looped callback
  keyboardDetectionController.addCallback((state) {
    print('Looped callback: $state');
    return true;
  });

  // Add looped future callback
  keyboardDetectionController.addCallback((state) async {
    await Future.delayed(const Duration(milliseconds: 100));
    print('Looped future callback: $state');
    return true;
  });

  super.initState();
}

Use the controller in the 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: ${keyboardDetectionController.state}'),
              FutureBuilder(
                future: keyboardDetectionController.ensureSizeLoaded,
                builder: (context, snapshot) {
                  if (snapshot.hasData) {
                    return Text('Keyboard size loaded: ${keyboardDetectionController.size}');
                  }
                  return const Text('Loading keyboard size...');
                },
              ),
              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'),
              ),
            ],
          ),
        ),
      ),
    ),
  );
}

Controller Methods

• keyboardDetectionController.state: Get the current keyboard visibility state as a KeyboardState enum.
• keyboardDetectionController.stateAsBool([bool includeTransitionalState = false]): Get the keyboard visibility as a bool?. If includeTransitionalState is true, transitional states (visibling, hiding) are included.
• keyboardDetectionController.addCallback(callback): Add a callback for state changes. Return true for repeated calls, false to stop.
• keyboardDetectionController.stream: Listen to keyboard visibility changes as a stream.
• keyboardDetectionController.size: Get the keyboard size. Use keyboardDetectionController.ensureSizeLoaded to ensure the size is loaded.

Limitations

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

Contributions

Contributions and feedback are welcome! Feel free to open issues or submit pull requests.