CODEWITHSUNDEEP
javaandroidbluetoothbluetooth-device-discovery
GeneCode
GeneCode

Reputation: 7588

Bluetooth start discovery not giving results

This is my first app in Android. I am very new to Android and Java. I am kind of expert in iOS/ObjC though. I am learning by doing. So I jumped straight into making an app to connect to a bluetooth device. First step is of course to get a list of the bluetooth device available in range.

Here is my manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest...>

    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <application ...

Here is my Activity code:

private BluetoothAdapter btAdapter;

    @Override
    public void onDestroy() {
        super.onDestroy();
       // Unregister broadcast listeners
        unregisterReceiver(mReceiver);
    }


    /*-------------  ON CREATE ------------------------------*/
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btAdapter =  BluetoothAdapter.getDefaultAdapter();
        if (btAdapter == null) {
            System.out.println ("Bluetooth non support");
        } else {
            System.out.println ("Bluetooth initialized");
        }

        IntentFilter filter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
        registerReceiver(mReceiver, filter);

        IntentFilter filterDevice = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        registerReceiver(mReceiver, filterDevice);

        if (btAdapter.isEnabled()) {
            String mydeviceaddress = btAdapter.getAddress();
            String mydevicename = btAdapter.getName();

            String status = mydevicename + " : " + mydeviceaddress;
            System.out.println(status);
            System.out.println ("Start discover");
            btAdapter.startDiscovery();
        } else {
            System.out.println ("Not enabled");
            Intent enableBT = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBT, 1);
        }
    }


    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();

            if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
                final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,
                        BluetoothAdapter.ERROR);
                switch (state) {
                    case BluetoothAdapter.STATE_OFF:
                        System.out.println("1");
                        break;
                    case BluetoothAdapter.STATE_TURNING_OFF:
                        System.out.println("2");
                        break;
                    case BluetoothAdapter.STATE_ON:
                        System.out.println("3");
                        // SCAN HERE
                        btAdapter.startDiscovery();
                        break;
                    case BluetoothAdapter.STATE_TURNING_ON:
                        System.out.println("4");
                        break;
                }
            }

            if (BluetoothDevice.ACTION_FOUND.equals(action))
            {
                // Get the BluetoothDevice object from the Intent
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                // Add the name and address to an array adapter to show in a ListView
                System.out.println(device.getName() + "\n" + device.getAddress());
            } else {
                System.out.println("What de fuq");
            }

        }
    };

I turned on bluetooth on my android phone, and then running the app shows that log:

Bluetooth initialized Start discover

And thats all. Other logs are not printing out. Any idea why? My code seems perfect idk.

EDIT: Screenshot of the Bluetooth module HC-05 being detected by Android. enter image description here

Upvotes: 0

Views: 2264

Answers (3)

Jos_BCN
Jos_BCN

Reputation: 81

In my case, I solved it with following permissions...

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

Upvotes: 0

Arnab Saha
Arnab Saha

Reputation: 511

If your other device is a bluetooth module, in your case Arduino, right?

If so, check this tutorial describing connection between Android device and HC05 module. bthc-05 to android tutorial

Also, based on this official sample: google sample - bluetooth chat

Alternatively, you could also have the following method that makes your device discoverable. And install it on two phones. Then you should be able to discover the phones on each other atleast.

protected void makeDiscoverable(){
    // Make local device discoverable
    Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
    discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, DISCOVERABLE_DURATION);
    startActivityForResult(discoverableIntent, DISCOVERABLE_BT_REQUEST_CODE);
}

Maybe these help!

Upvotes: 0

amitava
amitava

Reputation: 505

The other devices may not be in discoverable mode. Make sure they are discoverable.

Upvotes: 1

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