RxBluetooth

Android reactive bluetooth library. Basically, RxBluetooth is just wrapper around android BluetoothAdapter, so first of all the Bluetooth developer guide should be read.

RxBluetooth for RxJava 1 is available in respective branch.

Full documentation

• Wiki
• Javadoc

Usage

1. Create RxBluetooth instance.

   RxBluetooth rxBluetooth = new RxBluetooth(this); // `this` is a context

2. For android 6.0+ you need location permission.

   if (ContextCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
       ActivityCompat.requestPermissions(MainActivity.this, new String[] { android.Manifest.permission.ACCESS_COARSE_LOCATION }, REQUEST_PERMISSION_COARSE_LOCATION);
   }
   // And catch the result like this:
      @Override public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[],
          @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_PERMISSION_COARSE_LOCATION) {
          for (String permission : permissions) {
            if (android.Manifest.permission.ACCESS_COARSE_LOCATION.equals(permission)) {
              // Do stuff if permission granted
            }
          }
        }
      }

3. Check that bluetooth is available and enabled:

   // check if bluetooth is supported on your hardware
   if  (!rxBluetooth.isBluetoothAvailable()) {
      // handle the lack of bluetooth support
   } else {
      // check if bluetooth is currently enabled and ready for use
      if (!rxBluetooth.isBluetoothEnabled()) { 
         // to enable bluetooth via startActivityForResult()
         rxBluetooth.enableBluetooth(this, REQUEST_ENABLE_BT);
      } else {
         // you are ready
      }
   }

4. Have fun.

5. Make sure you are unsubscribing and stopping discovery in OnDestroy():

   if (rxBluetooth != null) {
         rxBluetooth.cancelDiscovery();
       }
   unsubscribe(rxBluetoothSubscription);

Observing devices

rxBluetooth.observeDevices()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .subscribe(new Consumer<BluetoothDevice>() {
      @Override public void accept(@NonNull BluetoothDevice bluetoothDevice) throws Exception {
        //
      }
    }));

Create connection to device

// Use 00001101-0000-1000-8000-00805F9B34FB for SPP service 
// (ex. Arduino) or use your own generated UUID.
UUID uuid = UUID.fromString("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx");

rxBluetooth.observeConnectDevice(bluetoothDevice, uuid)
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.io())
    .subscribe(new Consumer<BluetoothSocket>() {
      @Override public void accept(BluetoothSocket socket) throws Exception {
        // Connected to the device, do anything with the socket
      }
    }, new Consumer<Throwable>() {
      @Override public void accept(Throwable throwable) throws Exception {
        // Error occured
      }
    });

Observing discovery state

To observe just ACTION_DISCOVERY_STARTED:

rxBluetooth.observeDiscovery()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .filter(BtPredicate.in(BluetoothAdapter.ACTION_DISCOVERY_STARTED))
    .subscribe(new Consumer<String>() {
      @Override public void accept(String action) throws Exception {
        //
      }
    });

To observe both ACTION_DISCOVERY_STARTED and ACTION_DISCOVERY_FINISHED:

rxBluetooth.observeDiscovery()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .filter(BtPredicate.in(BluetoothAdapter.ACTION_DISCOVERY_STARTED, BluetoothAdapter.ACTION_DISCOVERY_FINISHED))
    .subscribe(new Consumer<String>() {
      @Override public void accept(String action) throws Exception {
        //
      }
    });

Observing bluetooth state

rxBluetooth.observeBluetoothState()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .filter(BtPredicate.in(BluetoothAdapter.STATE_ON))
    .subscribe(new Consumer<Integer>() {
      @Override public void accept(Integer integer) throws Exception {
        //
      }
    });

You can observe single or multiple states:

BluetoothAdapter.STATE_OFF
BluetoothAdapter.STATE_TURNING_ON
BluetoothAdapter.STATE_ON
BluetoothAdapter.STATE_TURNING_OFF

Observing scan mode

rxBluetooth.observeScanMode()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .filter(BtPredicate.in(BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE))
    .subscribe(new Consumer<Integer>() {
    @Override public void accept(Integer integer) throws Exception {
      //
    }
    });

You can observe single or multiple scan modes:

BluetoothAdapter.SCAN_MODE_NONE
BluetoothAdapter.SCAN_MODE_CONNECTABLE
BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE

Getting the profile proxy object

rxBluetooth.observeBluetoothProfile(myProfile)
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .subscribe(new Consumer<ServiceEvent>() {
    @Override public void accept(ServiceEvent serviceEvent) throws Exception {
      switch (serviceEvent.getState()) {
       case CONNECTED:
            BluetoothProfile bluetoothProfile = serviceEvent.getBluetoothProfile();
            List<BluetoothDevice> devices = bluetoothProfile.getConnectedDevices();
            for ( final BluetoothDevice dev : devices ) {
              //..
            }
            break;
       case DISCONNECTED:
            //serviceEvent.getBluetoothProfile() returns null
            break;
        }
      }
    });

myProfile can be one of BluetoothProfile.HEALTH, BluetoothProfile.HEADSET, BluetoothProfile.A2DP, BluetoothProfile.GATT or BluetoothProfile.GATT_SERVER

Clients should close profile proxy when they are no longer using the proxy obtained from observeBluetoothProfile:

rxBluetooth.closeProfileProxy(int profile, BluetoothProfile proxy);

Observing device state

To observe the current device state, you can receive the ConnectionStateEvent which provides the state, previous state, and BluetoothDevice.

rxBluetooth.observeConnectionState()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .subscribe(new Consumer<ConnectionStateEvent>() {
    @Override public void accept(ConnectionStateEvent event) throws Exception {
      switch (event.getState()) {
        case BluetoothAdapter.STATE_DISCONNECTED:
            // device disconnected
            break;
        case BluetoothAdapter.STATE_CONNECTING:
            // device connecting
            break;
        case BluetoothAdapter.STATE_CONNECTED:
            // device connected
            break;
        case BluetoothAdapter.STATE_DISCONNECTING:
            // device disconnecting
            break;
      }
    }
    });

Possible states are:

BluetoothAdapter.STATE_DISCONNECTED
BluetoothAdapter.STATE_CONNECTING
BluetoothAdapter.STATE_CONNECTED
BluetoothAdapter.STATE_DISCONNECTING

Observing device bond state

To observe the bond state of devices, you can receive the BondStateEvent which provides the state, previous state, and BluetoothDevice.

rxBluetooth.observeBondState()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .subscribe(new Consumer<BondStateEvent>() {
    @Override public void accept(BondStateEvent event) throws Exception {
      switch (event.getState()) {
        case BluetoothDevice.BOND_NONE:
            // device unbonded
            break;
        case BluetoothDevice.BOND_BONDING:
            // device bonding
            break;
        case BluetoothDevice.BOND_BONDED:
            // device bonded
            break;
      }
    }
    });

Possible states are:

BluetoothDevice.BOND_NONE
BluetoothDevice.BOND_BONDING
BluetoothDevice.BOND_BONDED

Read and Write with BluetoothSocket

After creating a connection to the device, you can use BluetoothConnection class to read and write with its socket.

Read:

BluetoothConnection bluetoothConnection = new BluetoothConnection(bluetoothSocket);

// Observe every byte received
bluetoothConnection.observeByteStream()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.io())
    .subscribe(new Consumer<Byte>() {
      @Override public void accept(Byte aByte) throws Exception {
        // This will be called every single byte received
      }
    }, new Consumer<Throwable>() {
      @Override public void accept(Throwable throwable) throws Exception {
        // Error occured
      }
    });

// Or just observe string
bluetoothConnection.observeStringStream()
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.io())
    .subscribe(new Consumer<String>() {
      @Override public void call(String string) throws Exception {
        // This will be called every string received
      }
    }, new Consumer<Throwable>() {
      @Override public void call(Throwable throwable) throws Exception {
        // Error occured
      }
    });

Write:

bluetoothConnection.send("Hello"); // String
bluetoothConnection.send("There".getBytes()); // Array of bytes

Close:

Remember to close streams and socket once you are done.

bluetoothConnection.closeConnection();

Observe ACL actions

rxBluetooth.observeAclEvent() //
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.computation())
    .subscribe(new Consumer<AclEvent>() {
      @Override public void accept(AclEvent aclEvent) throws Exception {
        switch (aclEvent.getAction()) {
          case BluetoothDevice.ACTION_ACL_CONNECTED:
            //...
            break;
          case BluetoothDevice.ACTION_ACL_DISCONNECT_REQUESTED:
            //...
            break;
          case BluetoothDevice.ACTION_ACL_DISCONNECTED:
            //...
            break;
        }
      }
    });

Download

Releases are available both in jcenter and mavenCentral repositories.

compile 'com.github.ivbaranov:rxbluetooth2:2.0.1'

Snapshots

Snapshots of the development version are available in Sonatype's snapshots repository.

In order to download from snapshot repository add:

repositories {
    maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
}

Contributing

Make sure you use SquareAndroid code style. (https://github.com/square/java-code-styles)

Create a branch for each feature.

Developed By

Ivan Baranov

License

Copyright 2015 Ivan Baranov

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.