react-native-ble-plx

After modifying your code (e.g., in App.tsx), use the following methods to reload the app and see your changes:

• Android: Press the <kbd>R</kbd> key twice, or open the Developer Menu (<kbd>Ctrl</kbd> + <kbd>M</kbd> on Windows/Linux or <kbd>Cmd ⌘</kbd> + <kbd>M</kbd> on macOS) and select "Reload".
• iOS: Press <kbd>Cmd ⌘</kbd> + <kbd>R</kbd> in the iOS Simulator.

If your project uses AndroidX, you must convert the library's import statements using jetifier. Add a postinstall script to your package.json to automate this:

1. Install jetifier: npm install --save-dev jetifier.
2. Add to package.json:

   "postinstall": "npx jetify"

To install the library in an ejected Expo project or a React Native project with version 0.60 or higher, follow these steps:

1. Install the package: npm install --save react-native-ble-plx.
2. Link the library: react-native link react-native-ble-plx.
3. Add a Swift file: Open the Xcode workspace in the ios folder and create a new empty Swift file. Accept the prompt to create an Objective-C bridging header.
4. Update Podfile: Add pod 'react-native-ble-plx', :path => '../node_modules/react-native-ble-plx' to your ios/Podfile.
5. Install pods: Run pod update inside the ios folder.

Requirements:

• Minimal iOS version: 8.0.
• For iOS 13+, add NSBluetoothAlwaysUsageDescription to your info.plist.

npm install --save react-native-ble-plx
react-native link react-native-ble-plx
# Inside ios folder
pod update

To enable background mode on iOS:

1. In your application target in Xcode, go to the Capabilities tab.
2. Enable Uses Bluetooth LE Accessories in the Background Modes section.
3. When initializing the BleManager, pass the restoreStateIdentifier and restoreStateFunction to the constructor.

Use the onDeviceDisconnected method on your BleManager instance to listen for disconnection events. This allows you to implement custom logic such as automatic reconnection or user notifications.

Note: Connection monitoring only occurs while the application is in the foreground.

const setupOnDeviceDisconnected = (deviceIdToMonitor: String) => {
  bleManagerInstance.onDeviceDisconnected(deviceIdToMonitor, disconnectedListener)
}

const disconnectedListener = (error: BleError | null, device: Device | null) => {
  if (error) {
    console.error(JSON.stringify(error, null, 4))
  }
  if (device) {
    console.info(JSON.stringify(device, null, 4))

    // reconnect to the device
    device.connect()
  }
}

To launch the application on an Android emulator or device, ensure the Metro Bundler is already running in a separate terminal, then execute the following command from the project root.

# using npm
npm run android

# OR using Yarn
yarn android

On iOS, the BLE stack is not immediately available upon launch. Use onStateChange() to listen for the PoweredOn state before attempting to scan or connect.

React.useEffect(() => {
  const subscription = manager.onStateChange(state => {
    if (state === 'PoweredOn') {
      scanAndConnect()
      subscription.remove()
    }
  }, true)
  return () => subscription.remove()
}, [manager])

Before running the application, you must start Metro, the JavaScript bundler that ships with React Native. Run this command from the root of your project.

# using npm
npm start

# OR using Yarn
yarn start

After calling device.connect(), you must call device.discoverAllServicesAndCharacteristics() before you can interact with the device's services and characteristics. Even if you already know the UUIDs, they must be discovered to be visible to the GATT client.

device
  .connect()
  .then(device => {
    return device.discoverAllServicesAndCharacteristics()
  })
  .then(device => {
    // A fully functional connection you can use, now you can read, write and monitor values
  })
  .catch(error => {
    // Handle errors
  })