如何知道应用程序的其他用户是否离我很近？

Question

我使用的是广播接收器，但我无法获得接近1公里的任何用户的位置。我无法理解这里有什么问题。 接收器的代码是。 。

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;
import android.util.Log;
import android.widget.Toast;

public class ProximityReciever extends BroadcastReceiver {

LocationManager locationManager;
double latitude, longitude;
Location location;
Context context;
private static final long MIN_DISTANCE = 1000;
private static final long MIN_TIME = 6000;
private static final int NOTIFICATION_ID = 1000;

@Override
public void onReceive(Context context, Intent intent) {
    Log.d("Proximity Reciever", "Inside Reciever");

    String k = LocationManager.KEY_LOCATION_CHANGED;

    // Key for determining whether user is leaving or entering

    this.context = context;
    boolean state = intent.getBooleanExtra(k, false);
    //Gives whether the user is entering or leaving in boolean form

    try {
        Log.d("ProxyReceiver_State", "Got the state:" + state);

        if (state) {
            // Call the Notification Service or anything else that you would like to do here
            Log.d("ProxyRe_State_true", "Someone Came in . . ");

            Toast.makeText(context, "Welcome to my Area", Toast.LENGTH_SHORT).show();
        } else {
            //Other custom Notification
            Toast.makeText(context, "Thank you for visiting my Area,come back again !!", Toast.LENGTH_SHORT).show();

        }
    } catch (Exception e) {
        Log.d("Proxy_Receiver", String.valueOf(e));
    }
}
}

使用此接收器的活动代码是：

import android.annotation.SuppressLint;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.Toast;

public class Proxy extends AppCompatActivity {

private GPS_Tracker gps_tracker;
private LocationManager locationManager;
private double lat = 0.0, long1 = 0.0;    //Defining Latitude & Longitude
float radius = 1000.0f;//in metres
private ProximityReciever reciever;

@SuppressLint("MissingPermission")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_proxy);

    //reciever = new ProximityReciever();

    //GPS tracker to know your current location . . ..
    //i have created another class for this 
    try {
        gps_tracker = new GPS_Tracker(Proxy.this);
        Log.d("Can Get Location:", String.valueOf(gps_tracker.canGetLocation()));
        if (gps_tracker.canGetLocation()) {
            lat = gps_tracker.getLatitude();
            long1 = gps_tracker.getLongitude();
            Log.d("Proxy_MyLocation", "Latitude: " + lat + "Longitude: " + long1);
            Toast.makeText(this, "My Location: Latitude: " + lat + " Longitude: " + long1, Toast.LENGTH_LONG).show();
        } else {
            gps_tracker.showSettingAlert();
        }
    } catch (Exception e) {
        Log.d("Proxy_Exception", String.valueOf(e));
    }

    //tryinh out things with Proxiity Reciever. . . .
    //calling it and which detects the other users . . . .
    try {
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        Log.d("Proxy_Manager", "Getting Location manager and sending intent");

        //Intent intent = new Intent("com.example.hp.proximityalert");
        Intent intent = new Intent("com.example.hp.proximityalert.ProximityAlert");

        PendingIntent pi = PendingIntent.getBroadcast(getApplicationContext(), 1, intent, 0);
        //PendingIntent pi = PendingIntent.getService(getApplicationContext(), 1, intent, 0);

        locationManager.addProximityAlert(lat, long1, radius, -1, pi);

        Log.d("Proxy_Manager", "Added PRoxy Alert");

        reciever = new ProximityReciever();

        //Receive something from the other activity . . .
        IntentFilter intentFilter = new IntentFilter("com.example.hp.proximityalert.ProximityAlert");
        //
        Log.d("Proxy_Manager", "Intent Filter . . . .");
        //
        intentFilter.setPriority(999);

        //this.registerReceiver(reciever, intentFilter);
        registerReceiver(reciever, intentFilter);

        Log.d("Proxy_Manager", "Receiver registered . . .");
    } catch (Exception e) {
        Log.d("Proxy_Proxy_error", String.valueOf(e));
    }

  }
}

我使用了当前位置并在我的位置周围创建了1公里半径的距离，以检测是否有相同应用的任何用户进入我的附近。 。 。 但即使在同一个房间里我也找不到其他用户

可以理解如何检测如何检测也使用相同应用程序的附近用户。 。 。