java - 我希望当用户使用 GPS 进入 10 米半径时收到通知

Question

我已经显示了当前位置，获取了纬度和经度。使用 CircleOptions 类围绕用户位置绘制圆圈。例如，假设有两部手机，我设置半径为 20 米。每当另一部手机进入 20 米半径内时，我想收到有人在我附近的通知。我将使用 firebase 进行实时位置获取。类似这样的问题很少，但其中没有一个有答案。任何帮助将不胜感激。

MainActivity.java

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.fragment.app.FragmentActivity;

import android.graphics.Color;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Toast;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMapOptions;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.model.CircleOptions;
import com.google.android.gms.maps.model.LatLng;

public class MainActivity extends FragmentActivity implements GoogleMap.OnMyLocationButtonClickListener,
       GoogleMap.OnMyLocationClickListener, OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks,
       LocationListener
{
   GoogleMap mMap;
   GoogleMapOptions options = new GoogleMapOptions();
   GoogleApiClient googleApiClient;
   LocationManager locationManager;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
       MapFragment mapFragment = (MapFragment) getFragmentManager()
               .findFragmentById(R.id.map);
       mapFragment.getMapAsync(this);
   }
   @Override
   public void onMapReady(GoogleMap map) {
       mMap = map;
       mMap.setMyLocationEnabled(true);
       mMap.setOnMyLocationButtonClickListener(this);
       mMap.setOnMyLocationClickListener(this);

       buildClient();
       options.mapType(GoogleMap.MAP_TYPE_SATELLITE)
               .compassEnabled(false)
               .rotateGesturesEnabled(false)
               .tiltGesturesEnabled(false);
   }
   private void buildClient() {
       googleApiClient = new GoogleApiClient.Builder(this.getApplicationContext())
               .addConnectionCallbacks(this)
               .addApi(LocationServices.API)
               .build();
       googleApiClient.connect();
   }
   @Override
   public boolean onMyLocationButtonClick() {
       Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT).show();
       // Return false so that we don't consume the event and the default behavior still occurs
       // (the camera animates to the user's current position).
       return false;

   }
   @Override
   public void onMyLocationClick(@NonNull Location location) {
       Toast.makeText(this, "Current location:\n" + location, Toast.LENGTH_LONG).show();
   }
   @Override
   public void onConnected(@Nullable Bundle bundle) {
       Location location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
       LocationRequest lr = new LocationRequest();
       lr.setInterval(1000);
       lr.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
       LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, lr, this);
       double currentLatitude = location.getLatitude();
       double currentLongitude = location.getLongitude();
       Toast.makeText(this.getApplicationContext(), "Current Lat : " +currentLatitude + " Long : " + currentLongitude, Toast.LENGTH_SHORT).show();
       mMap.addMarker(new MarkerOptions()
               .position(new LatLng(currentLatitude, currentLongitude))
               .title("Marker"));
       drawCircle(new LatLng(currentLatitude,currentLongitude));
   }
   private void drawCircle(LatLng point){
       // Instantiating CircleOptions to draw a circle around the marker
       CircleOptions circleOptions = new CircleOptions();
       circleOptions.center(point);
       circleOptions.radius(20);
       circleOptions.strokeColor(Color.BLACK);
       circleOptions.fillColor(0x30ff0000);
       circleOptions.strokeWidth(2);
       mMap.addCircle(circleOptions);
   }
   @Override
   public void onConnectionSuspended(int i) {

   }
   @Override
   public void onLocationChanged(Location location) {
       location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
       LocationRequest lr = new LocationRequest();
       lr.setInterval(1000);
       lr.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
       LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, lr, this);
       double currentLatitude = location.getLatitude();
       double currentLongitude = location.getLongitude();
       mMap.clear();
       mMap.moveCamera(CameraUpdateFactory.newLatLng(new LatLng(currentLatitude, currentLongitude)));
       mMap.animateCamera(CameraUpdateFactory.zoomTo(18));
       drawCircle(new LatLng(currentLatitude,currentLongitude));
   }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    android:name="com.google.android.gms.maps.MapFragment"
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    />

Answer 1

您可以使用地理围栏概念来检测第二部手机是否到达您的半径范围。地理围栏基本上是如何工作的？您有 2 部电话(考虑电话 A 和电话 B)。电话 A 的地理围栏半径为 20。当手机B进入手机A的20半径范围内时，地理围栏将被触发。

地理围栏 Android 开发者:https://developer.android.com/training/location/geofencing

您还可以使用第三方库进行地理围栏。我会向您推荐智能位置库。

GitHub:https://github.com/mrmans0n/smart-location-lib