CIS 470 Mobile App Development Lecture 13 Wenbing Zhao Department of Electrical Engineering and Computer Science Cleveland State University wenbing@ieee.org 11/13/2018 CIS 470: Mobile App Development

Location-Based Services Displaying Google Maps in your Android application Displaying zoom controls on the map Switching between the different map views Retrieving the address location touched on the map Performing geocoding and reverse geocoding Obtaining geographical data using GPS, Cell-ID, and WiFi triangulation Monitoring for a location 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Displaying Maps When creating an app, need to select “Google Maps Activity” Create an app and name it LBS 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Displaying Maps Also need to obtain the Maps API key (after you created your app) To get a Google Maps key, open the google_maps_api.xml file that was created in your LBS project Within this file is a link to create a new Google Maps key Copy and paste the link into your browser and follow the instructions Replace the YOUR_KEY_HERE placeholder in the google_maps_api.xml with your Google Maps key <resources> <!-- TODO: Before you run your application, you need a Google Maps API key. To get one, follow this link, follow the directions and press "Create" at the end: https://console.developers.google.com/flows/enableapi?apiid=maps_android_backend&keyType=CLIENT_SIDE_ANDROID&r=AD:71:B7:6F:62:AA:7E:A6:30:10:AC:DC:CF:36:36:2C:9D:A7:C1:CB%3Bcom.wenbing.lbs Once you have your key (it starts with "AIza"), replace the "google_maps_key" string in this file. --> <string name="google_maps_key" templateMergeStrategy="preserve" translatable="false">AIzaSyCHapqQ2PtdWBdKwhHX8RmLlrkzaWb7rdE</string> </resources> 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Zoom Control In activity_maps.xml, add maps:uiZoomControls=“true” <fragment xmlns:android="http://schemas.android.com/apk/res/android" xmlns:map="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/map" android:name="com.google.android.gms.maps.SupportMapFragment" android:layout_width="match_parent" android:layout_height="match_parent" map:uiZoomControls="true" tools:context="com.wenbing.lbs.MapsActivity" /> 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Changing Views By default, Google Maps is displayed in map view. You can change to satellite view programmatically by setting the map type: mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE); 11/13/2018 CIS 470: Mobile App Development

Navigating to a Specific Location Programmatically show the map around a specific location using moveCamera() method public void onMapReady(GoogleMap googleMap) { mMap = googleMap; // Add a marker in Sydney and move the camera LatLng sydney = new LatLng(-34, 151); mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney")); mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney)); // mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE); 11/13/2018 CIS 470: Mobile App Development

Getting the Location that was touched To get the latitude and longitude of a point on the Google Map that was touched, you must set a onMapClickListener on mMap in onMapReady() method mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() { @Override public void onMapClick(LatLng point) { Log.d("DEBUG","Map clicked [" + point.latitude + " / " + point.longitude + "]"); Geocoder geoCoder = new Geocoder(getBaseContext(), Locale.getDefault()); try { List<Address> addresses = geoCoder.getFromLocation(point.latitude,point.longitude,1); String add = ""; if (addresses.size() > 0) { for (int i=0; i<addresses.get(0).getMaxAddressLineIndex(); i++) add += addresses.get(0).getAddressLine(i) + "\n"; } Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show(); } catch (IOException e) { e.printStackTrace(); } LatLng p = new LatLng(point.latitude, point.longitude); mMap.moveCamera(CameraUpdateFactory.newLatLng(p)); } }); 11/13/2018 CIS 470: Mobile App Development

Geocoding and Reverse Geocoding Knowing latitude and longitude of a location, you can find out its address using a process known as reverse geocoding Google Maps in Android supports reverse geocoding via the Geocoder class The Geocoder object converts the latitude and longitude into an address using the getFromLocation() method 11/13/2018 CIS 470: Mobile App Development

Geocoding and Reverse Geocoding If you know the address of a location but want to know its latitude and longitude, you can do so via geocoding using getFromLocationName() method Geocoder geoCoder = new Geocoder(getBaseContext(), Locale.getDefault()); try { List<Address> addresses = geoCoder.getFromLocationName( "empire state building", 5); if (addresses.size() > 0) { LatLng p = new LatLng((int) (addresses.get(0).getLatitude()), (int) (addresses.get(0).getLongitude())); mMap.moveCamera(CameraUpdateFactory.newLatLng(p)); } } catch (IOException e) { e.printStackTrace(); 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Get Location Data Three means: GPS Cell tower triangulation WiFI In Android, use LocationManager Add permission in manifest To simulate GPS data received by the Android emulator, you use the Location Controls tool on the right-hand side of the emulator After starting the app, observe that the map on the emulator now animates to your current location. This indicates that the application has received the GPS data <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Get Location Data import android.support.v4.app.FragmentActivity; import android.os.Bundle; import android.util.Log; import com.google.android.gms.maps.CameraUpdateFactory; import com.google.android.gms.maps.GoogleMap; import com.google.android.gms.maps.OnMapReadyCallback; import com.google.android.gms.maps.SupportMapFragment; import com.google.android.gms.maps.model.LatLng; import com.google.android.gms.maps.model.MarkerOptions; import android.location.Address; import android.location.Geocoder; import android.widget.Toast; import java.io.IOException; import java.util.Locale; import java.util.List; import android.support.v4.app.ActivityCompat; import android.content.pm.PackageManager; import android.location.Location; import android.location.LocationListener; import android.location.LocationManager; import android.content.Context; 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development public class MapsActivity extends FragmentActivity implements OnMapReadyCallback { final private int REQUEST_COURSE_ACCESS = 123; boolean permissionGranted = false; LocationManager lm; LocationListener locationListener; private GoogleMap mMap; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_maps); SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() .findFragmentById(R.id.map); mapFragment.getMapAsync(this); } @Override public void onMapReady(GoogleMap googleMap) { mMap = googleMap; lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE); locationListener = new MyLocationListener(); if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_COURSE_ACCESS); return; }else{ permissionGranted = true; } 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development @Override public void onMapReady(GoogleMap googleMap) { // continue from previous slide if(permissionGranted) { lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener); } // Add a marker in Sydney and move the camera LatLng sydney = new LatLng(-34, 151); mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney")); mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney)); mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() { @Override public void onMapClick(LatLng point) { Log.d("DEBUG","Map clicked [" + point.latitude + " / " + point.longitude + "]"); Geocoder geoCoder = new Geocoder(getBaseContext(), Locale.getDefault()); try { List<Address> addresses = geoCoder.getFromLocation(point.latitude,point.longitude,1); String add = ""; if (addresses.size() > 0) { for (int i=0; i<addresses.get(0).getMaxAddressLineIndex(); i++) add += addresses.get(0).getAddressLine(i) + "\n"; } Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show(); } catch (IOException e) { e.printStackTrace(); } } }); } 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development @Override public void onPause() { super.onPause(); //---remove the location listener--- if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_COURSE_ACCESS); return; }else{ permissionGranted = true; } if(permissionGranted) { lm.removeUpdates(locationListener); } } @Override public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { switch (requestCode) { case REQUEST_COURSE_ACCESS: if (grantResults[0] == PackageManager.PERMISSION_GRANTED) { permissionGranted = true; } else { permissionGranted = false; } break; default: super.onRequestPermissionsResult(requestCode, permissions, grantResults); } } 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development private class MyLocationListener implements LocationListener { public void onLocationChanged(Location loc) { if (loc != null) { Toast.makeText(getBaseContext(), "Location changed : Lat: " + loc.getLatitude() + " Lng: " + loc.getLongitude(), Toast.LENGTH_SHORT).show(); LatLng p = new LatLng( (int) (loc.getLatitude()), (int) (loc.getLongitude())); mMap.moveCamera(CameraUpdateFactory.newLatLng(p)); mMap.animateCamera(CameraUpdateFactory.zoomTo(7)); } else { System.out.println("loc is null"); } Toast.makeText(getBaseContext(), "onLocation"+loc, Toast.LENGTH_SHORT).show(); } public void onProviderDisabled(String provider) { } public void onProviderEnabled(String provider) { } public void onStatusChanged(String provider, int status, Bundle extras) { } } } 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Monitoring a Location Do something when the user (who carries the Android phone with the app) is getting close to a location using the addProximityAlert() method import android.app.PendingIntent; import android.content.Intent; import android.net.Uri; //---use the LocationManager class to obtain locations data--- lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); //---PendingIntent to launch activity if the user is within some locations--- PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("http://www.amazon.com")), 0); lm.addProximityAlert(37.422006, -122.084095, 5, -1, pendingIntent); 11/13/2018 CIS 470: Mobile App Development

CIS 470: Mobile App Development Exercises (required) Refactor the demo app: Add two buttons for the map view and satellite view Add another button for displaying current location When clicking a location on the map, add a marker and move the camera to that location Add a EditText view and a button such that when you enter a valid address, the camera will move to that location 11/13/2018 CIS 470: Mobile App Development