react-native-ble-manager

This is a porting of https://github.com/don/cordova-plugin-ble-central project to React Native.

Requirements

RN 0.60+

RN 0.40-0.59 supported until 6.7.X RN 0.30-0.39 supported until 2.4.3

Supported Platforms

• iOS 8+
• Android (API 19+)

Install

npm i --save react-native-ble-manager

The library support the autolink feature.

Android - Update Manifest

// file: android/app/src/main/AndroidManifest.xml
...
    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
...

In Android API 29 >= you need to use "ACCESS_FINE_LOCATION" instead of "ACCESS_COARSE_LOCATION".

If you need communication while the app is not in the foreground you need the "ACCESS_BACKGROUND_LOCATION" permission.

iOS - Update Info.plist

In iOS >= 13 you need to add the NSBluetoothAlwaysUsageDescription string key.

Note

• Remember to use the start method before anything.
• If you have problem with old devices try avoid to connect/read/write to a peripheral during scan.
• Android API >= 23 require the ACCESS_COARSE_LOCATION permission to scan for peripherals. React Native >= 0.33 natively support PermissionsAndroid like in the example.
• Android API >= 29 require the ACCESS_FINE_LOCATION permission to scan for peripherals. React-Native 0.63.X started targeting Android API 29.
• Before write, read or start notification you need to call retrieveServices method

Example

The easiest way to test is simple make your AppRegistry point to our example component, like this:

// in your index.ios.js or index.android.js
import React, { Component } from "react";
import { AppRegistry } from "react-native";
import App from "react-native-ble-manager/example/App"; //<-- simply point to the example js!

AppRegistry.registerComponent("MyAwesomeApp", () => App);

Or, you can still look into the whole example folder for a standalone project.

Methods

start(options)

Init the module. Returns a Promise object. Don't call this multiple times.

Arguments

• options - JSON

The parameter is optional the configuration keys are:

• showAlert - Boolean - [iOS only] Show or hide the alert if the bluetooth is turned off during initialization
• restoreIdentifierKey - String - [iOS only] Unique key to use for CoreBluetooth state restoration
• queueIdentifierKey - String - [iOS only] Unique key to use for a queue identifier on which CoreBluetooth events will be dispatched
• forceLegacy - Boolean - [Android only] Force to use the LegacyScanManager

Examples

BleManager.start({ showAlert: false }).then(() => {
  // Success code
  console.log("Module initialized");
});

scan(serviceUUIDs, seconds, allowDuplicates, scanningOptions)

Scan for availables peripherals. Returns a Promise object.

Arguments

• serviceUUIDs - Array of String - the UUIDs of the services to looking for. On Android the filter works only for 5.0 or newer.
• seconds - Integer - the amount of seconds to scan.
• allowDuplicates - Boolean - [iOS only] allow duplicates in device scanning
• scanningOptions - JSON - [Android only] after Android 5.0, user can control specific ble scan behaviors:
  • numberOfMatches - Number - corresponding to setNumOfMatches
  • matchMode - Number - corresponding to setMatchMode
  • scanMode - Number - corresponding to setScanMode
  • reportDelay - Number - corresponding to setReportDelay

Examples

BleManager.scan([], 5, true).then(() => {
  // Success code
  console.log("Scan started");
});

stopScan()

Stop the scanning. Returns a Promise object.

Examples

BleManager.stopScan().then(() => {
  // Success code
  console.log("Scan stopped");
});

connect(peripheralId)

Attempts to connect to a peripheral. In many case if you can't connect you have to scan for the peripheral before. Returns a Promise object.

In iOS, attempts to connect to a peripheral do not time out (please see Apple's doc), so you might need to set a timer explicitly if you don't want this behavior.

Arguments

• peripheralId - String - the id/mac address of the peripheral to connect.

Examples

BleManager.connect("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX")
  .then(() => {
    // Success code
    console.log("Connected");
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

disconnect(peripheralId, force)

Disconnect from a peripheral. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral to disconnect.
• force - boolean - [Android only] defaults to true, if true force closes gatt connection and send the BleManagerDisconnectPeripheral event immediately to Javascript, else disconnects the connection and waits for disconnected state to close the gatt connection and then sends the BleManagerDisconnectPeripheral to the Javascript

Examples

BleManager.disconnect("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX")
  .then(() => {
    // Success code
    console.log("Disconnected");
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

enableBluetooth() [Android only]

Create the request to the user to activate the bluetooth. Returns a Promise object.

Examples

BleManager.enableBluetooth()
  .then(() => {
    // Success code
    console.log("The bluetooth is already enabled or the user confirm");
  })
  .catch((error) => {
    // Failure code
    console.log("The user refuse to enable bluetooth");
  });

checkState()

Force the module to check the state of BLE and trigger a BleManagerDidUpdateState event.

Examples

BleManager.checkState();

startNotification(peripheralId, serviceUUID, characteristicUUID)

Start the notification on the specified characteristic, you need to call retrieveServices method before. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• serviceUUID - String - the UUID of the service.
• characteristicUUID - String - the UUID of the characteristic.

Examples

BleManager.startNotification(
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
)
  .then(() => {
    // Success code
    console.log("Notification started");
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

startNotificationUseBuffer(peripheralId, serviceUUID, characteristicUUID, buffer) [Android only]

Start the notification on the specified characteristic, you need to call retrieveServices method before. The buffer will collect a number or messages from the server and then emit once the buffer count it reached. Helpful to reducing the number or js bridge crossings when a characteristic is sending a lot of messages. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• serviceUUID - String - the UUID of the service.
• characteristicUUID - String - the UUID of the characteristic.
• buffer - Integer - a number of message to buffer prior to emit for the characteristic.

Examples

BleManager.startNotification(
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  1234
)
  .then(() => {
    // Success code
    console.log("Notification started");
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

stopNotification(peripheralId, serviceUUID, characteristicUUID)

Stop the notification on the specified characteristic. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• serviceUUID - String - the UUID of the service.
• characteristicUUID - String - the UUID of the characteristic.

read(peripheralId, serviceUUID, characteristicUUID)

Read the current value of the specified characteristic, you need to call retrieveServices method before. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• serviceUUID - String - the UUID of the service.
• characteristicUUID - String - the UUID of the characteristic.

Examples

BleManager.read(
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
)
  .then((readData) => {
    // Success code
    console.log("Read: " + readData);

    const buffer = Buffer.Buffer.from(readData); //https://github.com/feross/buffer#convert-arraybuffer-to-buffer
    const sensorData = buffer.readUInt8(1, true);
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

write(peripheralId, serviceUUID, characteristicUUID, data, maxByteSize)

Write with response to the specified characteristic, you need to call retrieveServices method before. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• serviceUUID - String - the UUID of the service.
• characteristicUUID - String - the UUID of the characteristic.
• data - Byte array - the data to write.
• maxByteSize - Integer - specify the max byte size before splitting message

Data preparation

If your data is not in byte array format you should convert it first. For strings you can use convert-string or other npm package in order to achieve that. Install the package first:

npm install convert-string

Then use it in your application:

// Import/require in the beginning of the file
import { stringToBytes } from "convert-string";
// Convert data to byte array before write/writeWithoutResponse
const data = stringToBytes(yourStringData);

Feel free to use other packages or google how to convert into byte array if your data has other format.

Examples

BleManager.write(
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  data
)
  .then(() => {
    // Success code
    console.log("Write: " + data);
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

writeWithoutResponse(peripheralId, serviceUUID, characteristicUUID, data, maxByteSize, queueSleepTime)

Write without response to the specified characteristic, you need to call retrieveServices method before. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• serviceUUID - String - the UUID of the service.
• characteristicUUID - String - the UUID of the characteristic.
• data - Byte array - the data to write.
• maxByteSize - Integer - (Optional) specify the max byte size
• queueSleepTime - Integer - (Optional) specify the wait time before each write if the data is greater than maxByteSize

Data preparation

If your data is not in byte array format check info for the write function above.

Example

BleManager.writeWithoutResponse(
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  data
)
  .then(() => {
    // Success code
    console.log("Writed: " + data);
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

readRSSI(peripheralId)

Read the current value of the RSSI. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.

Examples

BleManager.readRSSI("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX")
  .then((rssi) => {
    // Success code
    console.log("Current RSSI: " + rssi);
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

requestConnectionPriority(peripheralId, connectionPriority) [Android only API 21+]

Request a connection parameter update. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• connectionPriority - Integer - the connection priority to be requested, as follows:
  • 0 - balanced priority connection
  • 1 - high priority connection
  • 2 - low power priority connection

Examples

BleManager.requestConnectionPriority("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX", 1)
  .then((status) => {
    // Success code
    console.log("Requested connection priority");
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

requestMTU(peripheralId, mtu) [Android only API 21+]

Request an MTU size used for a given connection. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• mtu - Integer - the MTU size to be requested in bytes.

Examples

BleManager.requestMTU("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX", 512)
  .then((mtu) => {
    // Success code
    console.log("MTU size changed to " + mtu + " bytes");
  })
  .catch((error) => {
    // Failure code
    console.log(error);
  });

retrieveServices(peripheralId[, serviceUUIDs])

Retrieve the peripheral's services and characteristics. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.
• serviceUUIDs - String[] - [iOS only] only retrieve these services.

Examples

BleManager.retrieveServices("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX").then(
  (peripheralInfo) => {
    // Success code
    console.log("Peripheral info:", peripheralInfo);
  }
);

refreshCache(peripheralId) [Android only]

refreshes the peripheral's services and characteristics cache Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.

Examples

BleManager.refreshCache("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX")
  .then((peripheralInfo) => {
    // Success code
    console.log("cache refreshed!");
  })
  .catch((error) => {
    console.error(error);
  });

getConnectedPeripherals(serviceUUIDs)

Return the connected peripherals. Returns a Promise object.

Arguments

• serviceUUIDs - Array of String - the UUIDs of the services to looking for.

Examples

BleManager.getConnectedPeripherals([]).then((peripheralsArray) => {
  // Success code
  console.log("Connected peripherals: " + peripheralsArray.length);
});

createBond(peripheralId,peripheralPin) [Android only]

Start the bonding (pairing) process with the remote device. If you pass peripheralPin(optional), bonding will be auto(without manual entering pin) Returns a Promise object. The promise is resolved when either new bond successfully created or bond already existed, otherwise it will be rejected.

Examples

BleManager.createBond(peripheralId)
  .then(() => {
    console.log("createBond success or there is already an existing one");
  })
  .catch(() => {
    console.log("fail to bond");
  });

removeBond(peripheralId) [Android only]

Remove a paired device. Returns a Promise object.

Examples

BleManager.removeBond(peripheralId)
  .then(() => {
    console.log("removeBond success");
  })
  .catch(() => {
    console.log("fail to remove the bond");
  });

getBondedPeripherals() [Android only]

Return the bonded peripherals. Returns a Promise object.

Examples

BleManager.getBondedPeripherals([]).then((bondedPeripheralsArray) => {
  // Each peripheral in returned array will have id and name properties
  console.log("Bonded peripherals: " + bondedPeripheralsArray.length);
});

getDiscoveredPeripherals()

Return the discovered peripherals after a scan. Returns a Promise object.

Examples

BleManager.getDiscoveredPeripherals([]).then((peripheralsArray) => {
  // Success code
  console.log("Discovered peripherals: " + peripheralsArray.length);
});

removePeripheral(peripheralId) [Android only]

Removes a disconnected peripheral from the cached list. It is useful if the device is turned off, because it will be re-discovered upon turning on again. Returns a Promise object.

Arguments

• peripheralId - String - the id/mac address of the peripheral.

isPeripheralConnected(peripheralId, serviceUUIDs)

Check whether a specific peripheral is connected and return true or false. Returns a Promise object.

Examples

BleManager.isPeripheralConnected(
  "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  []
).then((isConnected) => {
  if (isConnected) {
    console.log("Peripheral is connected!");
  } else {
    console.log("Peripheral is NOT connected!");
  }
});

Events

BleManagerStopScan

The scanning for peripherals is ended.

Arguments

• none

Examples

bleManagerEmitter.addListener("BleManagerStopScan", () => {
  // Scanning is stopped
});

BleManagerDidUpdateState

The BLE change state.

Arguments

• state - String - the new BLE state ('on'/'off').

Examples

bleManagerEmitter.addListener("BleManagerDidUpdateState", (args) => {
  // The new state: args.state
});

BleManagerDiscoverPeripheral

The scanning find a new peripheral.

Arguments

• id - String - the id of the peripheral
• name - String - the name of the peripheral
• rssi - Number - the RSSI value
• advertising - JSON - the advertising payload, here are some examples:
  • isConnectable - Boolean
  • serviceUUIDs - Array of String
  • manufacturerData - JSON - contains the raw bytes and data (Base64 encoded string)
  • serviceData - JSON - contains the raw bytes and data (Base64 encoded string)
  • txPowerLevel - Int

Examples

bleManagerEmitter.addListener("BleManagerDiscoverPeripheral", (args) => {
  // The id: args.id
  // The name: args.name
});

BleManagerDidUpdateValueForCharacteristic

A characteristic notify a new value.

Arguments

• value — Array — the read value
• peripheral — String — the id of the peripheral
• characteristic — String — the UUID of the characteristic
• service — String — the UUID of the characteristic

Event will only be emitted after successful startNotification.

Example

import { bytesToString } from "convert-string";
import { NativeModules, NativeEventEmitter } from "react-native";

const BleManagerModule = NativeModules.BleManager;
const bleManagerEmitter = new NativeEventEmitter(BleManagerModule);

async function connectAndPrepare(peripheral, service, characteristic) {
  // Connect to device
  await BleManager.connect(peripheral);
  // Before startNotification you need to call retrieveServices
  await BleManager.retrieveServices(peripheral);
  // To enable BleManagerDidUpdateValueForCharacteristic listener
  await BleManager.startNotification(peripheral, service, characteristic);
  // Add event listener
  bleManagerEmitter.addListener(
    "BleManagerDidUpdateValueForCharacteristic",
    ({ value, peripheral, characteristic, service }) => {
      // Convert bytes array to string
      const data = bytesToString(value);
      console.log(`Recieved ${data} for characteristic ${characteristic}`);
    }
  );
  // Actions triggereng BleManagerDidUpdateValueForCharacteristic event
}

BleManagerConnectPeripheral

A peripheral was connected.

Arguments

• peripheral - String - the id of the peripheral
• status - Number - [Android only] connect reasons

BleManagerDisconnectPeripheral

A peripheral was disconnected.

Arguments

• peripheral - String - the id of the peripheral
• status - Number - [Android only] disconnect reasons

BleManagerCentralManagerWillRestoreState [iOS only]

This is fired when centralManager:WillRestoreState: is called (app relaunched in the background to handle a bluetooth event).

Arguments

• peripherals - Array - an array of previously connected peripherals.

For more on performing long-term bluetooth actions in the background:

iOS Bluetooth State Preservation and Restoration

iOS Relaunch Conditions