I'm trying to manage several Bluetooth events from my app so the user will not need to leave the app & try to search/pair Bluetooth devices from Android settings.
I'm able to enumerate previously paired devices, and start discovery, however I cant find nearby devices.
Background info:
Device = Samsung Galaxy S6
OS = Android 6.0.1 , Kernel 3.4.0-750027
Bluetooth devices are visible via Android's own built in discovery
Here is my relevant code:
package experiment.xyz.abc;
import android.app.ListActivity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
/**
 *      
 * This activity is responsible for bluetooth device discovery, pairing, and selection.
 * 1) user can search for nearby devices
 * 2) pair with device
 * 3) unpair a device
 * 4) select a bt device( upon successful selection the activity navigates away).
 */
public class BluetDeviceListActivity extends ListActivity
{
 public static String BLUETOOTH_DEVICE_ADDRESS= "BLUETOOTH_DEVICE_ADDRESS";
    List<BluetoothDevice> bluetList;
    BluetoothDeviceListAdapter newBluetoothDeviceListAdapter = null;
    private  Set<BluetoothDevice> pairedDevices;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.bluet_list_view);
        //instantiate adapter
        newBluetoothDeviceListAdapter = new BluetoothDeviceListAdapter(this);
        //populate bluet list
        populatePairedBluetoothDevices();
        //set the ListActivity's adapter with our custom adapter
        setListAdapter(newBluetoothDeviceListAdapter);
        //on item click get the associated item based index & use Intent to send BluetoothDevice
        getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                BluetoothDevice bluetoothDevice= newBluetoothDeviceListAdapter.getListOfBluetoothDevices().get(position);
                if (bluetoothDevice!=null) {
                    Intent returnIntent = new Intent();
                    returnIntent.putExtra(BLUETOOTH_DEVICE_ADDRESS, bluetoothDevice.getAddress());
                    setResult(RESULT_OK, returnIntent);
                }
                finish();
                if (mReceiver!=null)
                {
                    try {
                        unregisterReceiver(mReceiver);
                    }
                    catch (IllegalArgumentException exc)
                    {
                        exc.printStackTrace();
                    }
                }
            }
        });
        //cancel activity dialog
        Button cancelButton = (Button) findViewById(R.id.cancelBluetoothDialogButton);
        cancelButton.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
                if (mReceiver!=null)
                {
                    try {
                        unregisterReceiver(mReceiver);
                    }
                    catch (IllegalArgumentException exc)
                    {
                        exc.printStackTrace();
                    }
                }
            }
        });
        //search for bluetooth devices
        Button searchAndPairButton = (Button) findViewById(R.id.searchPairButton);
        searchAndPairButton.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //update textview
                populateDiscoveredBluetoothDevices();
            }
        });
        //pair or unpair selected device
        Button pairOrUnpairButton = (Button) findViewById(R.id.pairUnpairDialogButton);
        pairOrUnpairButton.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //TODO:
            }
        });
    }//end onCreate
    //discover nearby devices & add to list
    private void populateDiscoveredBluetoothDevices()
   {
       StreamApiUtility.getBluetoothAdapter();
       //is bluet enabled
       BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
       if (mBluetoothAdapter != null && mBluetoothAdapter.isEnabled()) {
           //if already discovering cancel
           if(mBluetoothAdapter.isDiscovering()){
               mBluetoothAdapter.cancelDiscovery();
           }
           //start a new discovery
           mBluetoothAdapter.startDiscovery();
           }//end there are paired devices
           else
           {
               Log.i("EEGdataCapture", "No paired devices, select Search & Pair.");
               TextView textView  =(TextView) findViewById(R.id.textViewBluetoothListInstruction);
               textView.setText("No paired devices, select Search & Pair.");
           }
       }
    //query already paired & add to list
    private void populatePairedBluetoothDevices()
    {
        StreamApiUtility.getBluetoothAdapter();
        //is bluet enabled
        BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (mBluetoothAdapter != null && mBluetoothAdapter.isEnabled()) {
            //if already discovering cancel
            if(mBluetoothAdapter.isDiscovering()){
                mBluetoothAdapter.cancelDiscovery();
            }
            //start a new discovery
            mBluetoothAdapter.startDiscovery();
            //iterate paired/bonded devices and if there are any add them to the custom adapter
            pairedDevices = mBluetoothAdapter.getBondedDevices();
            if (pairedDevices.size() > 0) {
                BluetoothDevice bluetoothDevice;
                Iterator<BluetoothDevice> it = pairedDevices.iterator();
                while (it.hasNext()) {
                    bluetoothDevice = (BluetoothDevice) it.next();
                    //add to adapter
                    newBluetoothDeviceListAdapter.addDevice(bluetoothDevice);
                    newBluetoothDeviceListAdapter.notifyDataSetChanged();
                    Log.i("EEGdataCapture", "paired device, name: " + bluetoothDevice.getName() + ", address: " + bluetoothDevice.getAddress());
                }
            }//end there are paired devices
            else
            {
                Log.i("EEGdataCapture", "No paired devices, select Search & Pair.");
                TextView textView  =(TextView) findViewById(R.id.textViewBluetoothListInstruction);
                textView.setText("No paired devices, select Search & Pair.");
            }
        }
    }
    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            BluetoothDevice device;
            if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                Log.i("EEGdataCapture", "BluetoothDevice.ACTION_FOUND");
                Log.i("EEGdataCapture", device.getName() + "\n" + device.getAddress());
                //update list
                newBluetoothDeviceListAdapter.addDevice(device);
                newBluetoothDeviceListAdapter.notifyDataSetChanged();
            }
            else if (BluetoothDevice.ACTION_BOND_STATE_CHANGED.equals(action)) {
                Log.i("EEGdataCapture", "BluetoothDevice.ACTION_BOND_STATE_CHANGED");
                final int state = intent.getIntExtra(BluetoothDevice.EXTRA_BOND_STATE, BluetoothDevice.ERROR);
                final int prevState = intent.getIntExtra(BluetoothDevice.EXTRA_PREVIOUS_BOND_STATE, BluetoothDevice.ERROR);
                if (state == BluetoothDevice.BOND_BONDED && prevState == BluetoothDevice.BOND_BONDING) {
                    Toast.makeText(MyApp.getAppContext(), "Paired", Toast.LENGTH_SHORT).show();
                } else if (state == BluetoothDevice.BOND_NONE && prevState == BluetoothDevice.BOND_BONDED) {
                    Toast.makeText(MyApp.getAppContext(), "Unpaired", Toast.LENGTH_SHORT).show();
                }
            }
            else if (BluetoothDevice.ACTION_UUID.equals(action)) {
                Log.i("EEGdataCapture", "BluetoothDevice.ACTION_UUID");
            }
            else if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
                Log.i("EEGdataCapture", "BluetoothAdapter.ACTION_DISCOVERY_STARTED, Discovery Started...");
            }
            else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
                Log.i("EEGdataCapture", "BluetoothAdapter.ACTION_DISCOVERY_FINISHED, Discovery finished.");
        }
            else
            {
                Log.i("EEGdataCapture", "BluetoothAdapter, ACTIOM is not supported, action ="+action);
            }
        }};
    private void pairDevice(BluetoothDevice device) {
        try {
            Method method = device.getClass().getMethod("createBond", (Class[]) null);
            method.invoke(device, (Object[]) null);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    private void unpairDevice(BluetoothDevice device) {
        try {
            Method method = device.getClass().getMethod("removeBond", (Class[]) null);
            method.invoke(device, (Object[]) null);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Override
    protected void onPause() {
        super.onPause();
        if ( StreamApiUtility.getBluetoothAdapter()!=null) {
            StreamApiUtility.getBluetoothAdapter().cancelDiscovery();
        }
        if (mReceiver!=null)
        {
            try {
                unregisterReceiver(mReceiver);
            }
            catch (IllegalArgumentException exc)
            {
                exc.printStackTrace();
            }
        }
    }
    @Override
    protected void onResume()
     {
         super.onResume();
         //filter to capture bluet events
         IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
         filter.addAction(BluetoothDevice.ACTION_UUID);
         filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
         filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
         //register listener for bluet events before starting discovery again
         registerReceiver(mReceiver, filter);
     }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mReceiver!=null)
        {
            try {
                unregisterReceiver(mReceiver);
            }
            catch (IllegalArgumentException exc)
            {
                exc.printStackTrace();
            }
        }
    }
}
updated Manifest:
 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
The BroadcastReciever's BluetoothDevice.ACTION_FOUND is not being triggered/called although ACTION_DISCOVERY_STARTED OR ACTION_DISCOVERY_FINISHED are being called.
Help please???
Thanks
Make sure Bluetooth is turned on. Touch and hold Bluetooth . In the list of paired devices, tap a paired but unconnected device. When your phone and the Bluetooth device are connected, the device shows as "Connected."
To start discovering devices, call startDiscovery() . The process is asynchronous and returns a boolean value indicating whether discovery has successfully started. The discovery process usually involves an inquiry scan of about 12 seconds, followed by a page scan of each device found to retrieve its Bluetooth name.
The UUID is used for uniquely identifying information. It identifies a particular service provided by a Bluetooth device. The standard defines a basic BASE_UUID: 00000000-0000-1000-8000-00805F9B34FB . Devices such as healthcare sensors can provide a service, substituting the first eight digits with a predefined code.
Your code seems ok. I guess you have the BLUETOOTH permission (otherwise you wouldn't receive the ACTION_DISCOVERY_STARTED) but do you also have the ACCESS_COARSE_LOCATION permission ?
You need it to receive ACTION_FOUND :
ACTION_FOUND
Broadcast Action: Remote device discovered.
RequiresBLUETOOTHandACCESS_COARSE_LOCATIONto receive.
You need to perform a realtime-Permission check to ensure that Coarse Location is enabled before discovering any devices. To do this, you should be targeting/minimum SDK 23+ in your build.gradle file.
if (mActivityContext.checkSelfPermission("android.permission.ACCESS_COARSE_LOCATION") == PackageManager.PERMISSION_GRANTED) {
        final BluetoothManager bluetoothManager =
                (BluetoothManager) mActivityContext.getSystemService(Context.BLUETOOTH_SERVICE);
        if (bluetoothManager != null) mBleAdapter = bluetoothManager.getAdapter();
Register Intent Filters here
        mBleAdapter.startDiscovery();
    } else {
        mInterface.requestPermission(Manifest.permission.ACCESS_COARSE_LOCATION, mCoarsePermissionTag);
    }
mInterface is my interface back to my MainActivity
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