CODEWITHSUNDEEP
androidbluetoothbeacon
AmiguelS
AmiguelS

Reputation: 855

AltBeacon Beacon creation App

I need to create a super simple app that just creates a detectable Bluetooth LE beacon, there is no need to transmit any data. I have chosen to use the AltBeacon lybrary, and as such I implemented the app with one of the examples they provide. Still, the app crashes with java.lang.NullPointerException: Attempt to invoke virtual method 'void android.bluetooth.le.BluetoothLeAdvertiser.startAdvertising(android.bluetooth.le.AdvertiseSettings, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseCallback)' on a null object reference I get positive result on both null checks I perform, so I'm not sure what else I could do on my side. Has anyone had any trouble with this library?

The code bellow is 98% the example available here. I'm using Android 5.0.

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

import org.altbeacon.beacon.Beacon;
import org.altbeacon.beacon.BeaconParser;
import org.altbeacon.beacon.BeaconTransmitter;

import java.util.Arrays;
import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity {

    BeaconTransmitter beaconTransmitter;
    Beacon beacon;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        beacon = new Beacon.Builder()
                .setId1("2f234454-cf6d-4a0f-adf2-f4911ba9ffa6")
                .setId2("1")
                .setId3("2")
                .setManufacturer(0x0118)
                .setTxPower(-59)
                .setDataFields(Arrays.asList(new Long[]{0l}))
                .build();

        if(beacon==null)
            Toast.makeText(getApplicationContext(), "NULL beacon", Toast.LENGTH_LONG).show();
        else
            Toast.makeText(getApplicationContext(), "OK beacon", Toast.LENGTH_LONG).show();

        BeaconParser beaconParser = new BeaconParser().setBeaconLayout("m:2-3=beac,i:4-19,i:20-21,i:22-23,p:24-24,d:25-25");
        beaconTransmitter = new BeaconTransmitter(getApplicationContext(), beaconParser);

        if(beaconTransmitter==null)
            Toast.makeText(getApplicationContext(), "NULL beacon trasmitter", Toast.LENGTH_LONG).show();
        else
            Toast.makeText(getApplicationContext(), "OK beacon trasmitter", Toast.LENGTH_LONG).show();

        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
             @Override
            public void run() {
                beaconTransmitter.startAdvertising(beacon);
            }
        }, 5000);


    }
}

Upvotes: 0

Views: 1289

Answers (2)

Clement Tong
Clement Tong

Reputation: 46

I know this is an old post and it might not be related but remember to turn on Bluetooth! That was the reason that threw an error at me!

Upvotes: 0

Javad Jafari
Javad Jafari

Reputation: 730

you need to check peripheral mode support of your device first. using this code will help u

BluetoothManager btManager = (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
            BluetoothAdapter btAdapter = btManager.getAdapter();
            if (btAdapter.isEnabled()) 
               boolean isSupported = btAdapter.isMultipleAdvertisementSupported()) ;

Upvotes: 4

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