How to display detected beacons in recycler view based on distance using ALT beacon

Question

Hi i am developing an android app using ALT beacon library.I need to display the detected beacons in a recycler view based on the distance.The nearby distance beacon need to display first in list.I had done evrything But i am getting blank page.Beacons are not displaying in recyclerview.Please help me.

ArrayList<Beacon> data;
 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    recyclerView = findViewById(R.id.Recyclerview_tab);
    bt_stop =  findViewById(R.id.bt_stop);
    bt_start =  findViewById(R.id.bt_start);

    beaconManager = BeaconManager.getInstanceForApplication(this);

    beaconManager.getBeaconParsers().add(new BeaconParser()
            .setBeaconLayout("m:2-3=0215,i:4-19,i:20-21,i:22-23,p:24-24,d:25-25"));

    beaconManager.setBackgroundBetweenScanPeriod(30000l);
    beaconManager.setForegroundBetweenScanPeriod(10000l);
    region = new Region("myMonitoringUniqueId", null, null, null);

adapter=new Beaconadapter(this); recyclerView.setAdapter(adapter);

    bt_start.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            beaconManager.bind(Main2Activity.this);
            Toast.makeText(Main2Activity.this, "clicked", Toast.LENGTH_SHORT).show();

        }
    });
    bt_stop.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            beaconManager.unbind(Main2Activity.this);

        }
    });
}

@Override
public void onBeaconServiceConnect() {

    final Region region = new Region("myBeaons", Identifier.parse("e2c56db5-dffb-48d2-b060-d0f5a71096e0"), null, null);

    beaconManager.addMonitorNotifier(new MonitorNotifier() {
                                         @Override
                                         public void didEnterRegion(Region region) {
                                             try {
                                                 Log.d(TAG, "didEnterRegion");
                                                 beaconManager.startRangingBeaconsInRegion(region);
                                             } catch (RemoteException e) {
                                                 e.printStackTrace();
                                             }
                                         }

                                         @Override
                                         public void didExitRegion(Region region) {
                                             try {
                                                 Log.d(TAG, "didExitRegion");
                                                 beaconManager.stopRangingBeaconsInRegion(region);
                                             } catch (RemoteException e) {
                                                 e.printStackTrace();
                                             }
                                         }

                                         @Override
                                         public void didDetermineStateForRegion(int i, Region region) {

                                         }
                                     });

        beaconManager.addRangeNotifier(new RangeNotifier() {
            @Override
            public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
                if (beacons.size() > 0) {

adapter.initAll(beacons);

Log.i(TAG, "The first beacon I see is about "+beacons.iterator().next().getDistance()+" meters away."); } adapter.notifyDataSetChanged();

            }
        });

        try {
            beaconManager.startRangingBeaconsInRegion(new Region("myRangingUniqueId", null, null, null));
        } catch (RemoteException e) {    }


}

My adapter code:

public class Beaconadapter extends RecyclerView.Adapter<Beaconadapter.Myviewholder> {
Context mcontext;

public static  ArrayList<Beacon> beacons;

private LayoutInflater inflater;


public Beaconadapter(Context mcontext) {
    this.mcontext = mcontext;
    this.beacons = new ArrayList<Beacon>();
    this.inflater = LayoutInflater.from(mcontext);


}

@NonNull
@Override
public Myviewholder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    View v= LayoutInflater.from(mcontext).inflate(R.layout.beaconrecyclerview,viewGroup,false);
    Myviewholder myviewholder=new Myviewholder(v);
    return myviewholder;    }

@Override
public void onBindViewHolder(@NonNull Myviewholder myviewholder, int i) {
    myviewholder.tv_uuid.setText(beacons.get(i).getServiceUuid());
    myviewholder.tv_macid2.setText(beacons.get(i).getBluetoothAddress());
    myviewholder.tv_rssi2.setText((int) beacons.get(i).getDistance());

}

@Override
public int getItemCount() {
    return beacons.size();
}

public void initAll(Collection newBeacons) {

    this.beacons.clear();
    this.beacons.addAll(newBeacons);


}

public static class Myviewholder extends RecyclerView.ViewHolder{ TextView tv_uuid,tv_macid2,tv_rssi2;

    public Myviewholder(@NonNull View itemView) {
        super(itemView);

        this.tv_uuid=itemView.findViewById(R.id.tv_uuid);
        this.tv_macid2=itemView.findViewById(R.id.tv_macid2);
        this.tv_rssi2=itemView.findViewById(R.id.tv_rssi2);


    }
}

}

Answer 1

A few tips:

1. Move your code that starts ranging to didDetermineStateForRegion. If you are already "in region" when you start monitoring, you won't get a new callback to didEnterRegion. You always get a callback to didDetermineStateForRegion.

2. Add debug lines to the top of each callback method. Then run your code to determine which methods get called: onBeaconServiceConnected, didEnterRegion, didDetermineStateForRegion, didRangeBeaconsInRegion get called.

3. If one method in the chain of events does not get called, try to figure out why. Each time you get one callback working, repeat step 2 above. This is the tried and true means of debugging a program.