SkaleKit for Flutter

A Flutter plugin for connecting to Skale smart coffee scales via Bluetooth Low Energy (BLE).

Features

Real-time weight updates
Device discovery with native picker UI
Tare (zero) function
Battery level monitoring
Button event detection (circle and square buttons)
Auto-connect support
LED display control (iOS only)

Platform Support

Platform	Support
iOS	12.0+
Android	API 21+

Installation

Add skale_kit to your pubspec.yaml:

dependencies:
  skale_kit: ^1.0.3

iOS Setup

Add the following keys to your Info.plist:

<key>NSBluetoothAlwaysUsageDescription</key>
<string>This app needs Bluetooth access to connect to your Skale coffee scale.</string>
<key>NSBluetoothPeripheralUsageDescription</key>
<string>This app needs Bluetooth access to connect to your Skale coffee scale.</string>

Android Setup

The plugin automatically adds the required permissions to your AndroidManifest.xml. However, you'll need to request permissions at runtime using a package like permission_handler.

Usage

Basic Example

import 'package:skale_kit/skale_kit.dart';

// Create an instance
final skaleKit = SkaleKit();

// Listen to connection state changes
skaleKit.connectionStateStream.listen((state) {
  print('Connection state: $state');
});

// Listen to weight updates
skaleKit.weightStream.listen((weight) {
  print('Weight: ${weight}g');
});

// Listen to button presses
skaleKit.buttonStream.listen((button) {
  print('Button pressed: $button');
});

// Show device picker and connect
final device = await skaleKit.showDevicePicker();

// Tare the scale
await skaleKit.tare();

// Get battery level
final batteryLevel = await skaleKit.getBatteryLevel();
print('Battery: $batteryLevel%');

// Disconnect
await skaleKit.disconnect();

// Don't forget to dispose
skaleKit.dispose();

Permission Handling

Before connecting, ensure you have the required permissions:

import 'package:permission_handler/permission_handler.dart';

Future<void> requestPermissions() async {
  if (Platform.isAndroid) {
    await [
      Permission.bluetoothScan,
      Permission.bluetoothConnect,
      Permission.locationWhenInUse,
    ].request();
  }
}

Auto-Connect

By default, auto-connect is disabled. This means showDevicePicker() will display the device selection UI each time.

To enable auto-connect (automatically reconnect to the last connected device):

// Enable auto-connect
await skaleKit.setAutoConnect(true);

// Disable auto-connect (default)
await skaleKit.setAutoConnect(false);

Note: When auto-connect is enabled, showDevicePicker() may not show the device picker UI if a previously connected device is available.

Error Handling

The plugin uses typed exceptions for error handling:

try {
  await skaleKit.showDevicePicker();
} on BluetoothDisabledError {
  print('Please enable Bluetooth');
} on PermissionDeniedError {
  print('Bluetooth permissions required');
} on CancelledError {
  print('User cancelled device selection');
} on SkaleError catch (e) {
  print('Error: $e');
}

API Reference

SkaleKit

Method	Description
`showDevicePicker()`	Shows native device picker UI
`connect(device)`	Connects to a specific device
`disconnect()`	Disconnects from current device
`tare()`	Tares (zeros) the scale
`getBatteryLevel()`	Returns battery percentage (0-100)
`setLEDDisplay(bool)`	Controls LED display (iOS only)
`setAutoConnect(bool)`	Enables/disables auto-connect (default: false)
`startScan()`	Starts scanning for devices
`stopScan()`	Stops scanning
`isBluetoothEnabled()`	Checks if Bluetooth is enabled
`hasPermissions()`	Checks if permissions are granted
`dispose()`	Releases resources

Streams

Stream	Type	Description
`weightStream`	`Stream<double>`	Real-time weight in grams
`connectionStateStream`	`Stream<SkaleConnectionState>`	Connection state changes
`buttonStream`	`Stream<SkaleButton>`	Button press events
`deviceStream`	`Stream<List<SkaleDevice>>`	Discovered devices

Enums

SkaleConnectionState

disconnected
scanning
connecting
connected

SkaleButton

circle (value: 1)
square (value: 2)

Error Types

BluetoothDisabledError - Bluetooth is disabled
PermissionDeniedError - Required permissions not granted
DeviceNotFoundError - Device was not found
ConnectionFailedError - Failed to connect
ConnectionLostError - Connection was lost
ConnectionTimeoutError - Connection timed out
AlreadyConnectedError - Already connected to a device
CancelledError - Operation was cancelled
UnknownError - Unknown error occurred

Native SDK Integration

This plugin wraps the native SkaleKit SDKs:

iOS: SkaleKit.xcframework
Android: skalekit-1.0.0.aar

The native SDKs must be placed in the following locations:

iOS: ios/Frameworks/SkaleKit.xcframework
Android: android/libs/skalekit-1.0.0.aar

Contributing

Contributions are welcome! Please read our contributing guidelines before submitting a pull request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Support

For issues and feature requests, please file an issue on GitHub.