Proximity Alert In Android

What are Proximity Alerts?

—- Till date we always use alert system to give alert on specific time i.e. on Birthday’s, Anniversary etc.. But what if we don’t know exact time but we know place consider example that you want to fix your glasses when you go nearby your glass repair store. So you exactly don’t know when you are going there but whenever you go you want a reminder that you are nearby your glass store & repair your glass. For these purpose proximity alerts are used.To achieve this we want help from LocationManager class & we need to create a BroadcastReceiver to recive proximity event & also we need to create a pending event.

I am considering you are aware of LocationManager, BroadcastReceiver & Pending Intent.

To create proximity alert we need latitude & longitude of the location for which you want to create alert, then redius (It will create a circle around given lat & lon of this redius & whenever we enter or exit this circle it will give alert) & pending Intent & expire time (this alert will active only for this given miliesconds if you want unlimited time simply keep it to -1)

Lets go for some code instead of theory

1) Main Layout (main.xml)— Here I am creating a layout which has two textbox to enter latitude & longitude & a button to add proximity alert.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<EditText
              android:id="@+id/point_latitude"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_marginLeft="25dip"
              android:layout_marginRight="25dip"
              android:hint="Latitude"
       />

       <EditText
              android:id="@+id/point_longitude"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_marginLeft="25dip"
              android:layout_marginRight="25dip"
              android:hint="Longitude"
       />
       <Button
              android:id="@+id/add_alert_button"
              android:text="Add Alert"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
       />

</LinearLayout>

2) Main Activity ProximityAlertActivity.java

public class ProximityAlertActivity extends Activity {
       private static final long MINIMUM_DISTANCECHANGE_FOR_UPDATE = 1; // in Meters
       private static final long MINIMUM_TIME_BETWEEN_UPDATE = 1000; // in Milliseconds
       private static final long POINT_RADIUS = 100; // in Meters
       private static final long PROX_ALERT_EXPIRATION = -1; // It will never expire
       private static final String PROX_ALERT_INTENT = "com.androidmyway.demo.ProximityAlert";
private LocationManager locationManager;
private EditText latitudeEditText;
       private EditText longitudeEditText;
       private Button addAlertButton;

       @Override
       public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
              setContentView(R.layout.main);

              locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

              latitudeEditText = (EditText) findViewById(R.id.point_latitude);
              longitudeEditText = (EditText) findViewById(R.id.point_longitude);
              addAlertButton = (Button) findViewById(R.id.add_alert_button);

              addAlertButton.setOnClickListener(new OnClickListener() {
                     public void onClick(View v) {
                            addProximityAlert();
                     }
              });

       }

       private void addProximityAlert() {
              double latitude = Double.parseDouble(latitudeEditText.getText().toString());
              double longitude = Double.parseDouble(longitudeEditText.getText().toString());
              Intent intent = new Intent(PROX_ALERT_INTENT);
              PendingIntent proximityIntent = PendingIntent.getBroadcast(this, 0, intent, 0);
locationManager.addProximityAlert(
                     latitude, // the latitude of the central point of the alert region
                     longitude, // the longitude of the central point of the alert region
                     POINT_RADIUS, // the radius of the central point of the alert region, in meters
                     PROX_ALERT_EXPIRATION, // time for this proximity alert, in milliseconds, or -1 to indicate no                           expiration
                     proximityIntent // will be used to generate an Intent to fire when entry to or exit from the alert region is detected
              );

              IntentFilter filter = new IntentFilter(PROX_ALERT_INTENT);
              registerReceiver(new ProximityIntentReceiver(), filter);
              Toast.makeText(getApplicationContext(),"Alert Added",Toast.LENGTH_SHORT).show();
       }
}

3)ProximityReceiver.java

public class ProximityIntentReceiver extends BroadcastReceiver {
       private static final int NOTIFICATION_ID = 1000;

       @Override
       public void onReceive(Context context, Intent intent) {
String key = LocationManager.KEY_PROXIMITY_ENTERING;
Boolean entering = intent.getBooleanExtra(key, false);
if (entering) {
                     Log.d(getClass().getSimpleName(), "entering");
              }else {
                     Log.d(getClass().getSimpleName(), "exiting");
              }
              NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

              Intent notificationIntent = new Intent(context, ProximityAlertActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
Notification notification = createNotification();
              notification.setLatestEventInfo(context, "Proximity Alert!", "You are near your point of interest.", pendingIntent);

              notificationManager.notify(NOTIFICATION_ID, notification);
      }

       private Notification createNotification() {
              Notification notification = new Notification();
notification.icon = R.drawable.ic_menu_notifications;
              notification.when = System.currentTimeMillis();
              notification.flags |= Notification.FLAG_AUTO_CANCEL;
              notification.flags |= Notification.FLAG_SHOW_LIGHTS;
notification.defaults |= Notification.DEFAULT_VIBRATE;
              notification.defaults |= Notification.DEFAULT_LIGHTS;
notification.ledARGB = Color.WHITE;
              notification.ledOnMS = 1500;
              notification.ledOffMS = 1500;
              return notification;
        }
}

You need to add following uses permission in your menifest file

       <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
       <uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
       <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
       <uses-permission android:name="android.permission.VIBRATE" />

This article is based on  Developing Proximity Alerts for Mobile Applications using the Android Platform

You can download code from https://github.com/sandipmjadhav/Proximity-Alert

Thank You