1. Location-Based Services: Part 2 (Google Maps)

2. Accessing Google Maps Google maps can be accessed in two ways
Through a browser or a WebView
Through the Google Maps Android API
(a.k.a., Google Maps Android API v2)
Google Maps Android API
allows you to incorporate Google Maps into applications
is distributed as part of the Google Play Services SDK
encapsulates maps in a MapFragment or a SupportMapFragment
MapFragment and SupportMapFragment essentially replace the
MapActivity class used in an earlier version of Google Maps API.
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3. Google Maps Android API
Using Google Maps Android API, you can
Add maps to your app
3D maps − terrain maps
satellite maps − etc.
Customize the map
markers − image overlays
polylines/polygons − etc.
Control the user’s view
zoom − pan
rotate − etc.
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4. Attribution Requirements
If you use the Google Maps Android API in your application, you must include the Google Play Services attribution text as part of a “Legal Notices” section in your application. Including legal notices as an independent menu item, or as part of an “About” menu item, is recommended.
The attribution text is available by making a call to method
GooglePlayServicesUtil.getOpenSourceSoftwareLicenseInfo()
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5. Download Google Repository (Android SDK Manager)
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6. Getting Started
Make sure that Google Repository is installed, as shown in the previous slide.
Obtain a Google Maps API key.
register a project in the Google APIs Console
get a Google Maps key associated with the signing certificate and package for your app
Add the required settings in your application’s manifest.
Add a map to your application.
Test your application
Android Studio greatly simplifies the middle three steps.
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7. Creating a New Application with a Google Maps Activity
Using Android Studio, start with a Google Maps Activity when creating a new project or add a Google Maps Activity to an existing project.
The resource google_maps_api.xml contains the information and steps needed to obtain a Google Maps API key.
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8. Example: google_maps_api.xml (in src/debug/res/values)
<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: You can also add your credentials to an existing key, using these values: ... SHA-1 certificate fingerprint: C9:95:96:58:E5:7C:58:32:FC:B8:0F:2D:9F:CD:5C:CF:94:BC:54:E4
(continued on next slide)
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9. Example: google_maps_api.xml (in src/debug/res/values)
Alternatively, follow the directions here: 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">YOUR_KEY_HERE</string> </resources>
A sample key looks like “AIzaSyCNs7mQEGMgQG…” (39 characters)
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10. Restrict the Key’s Use to Android Apps
To improve your application’s security, you should restrict the key’s usage to “Android apps” in the API Console. A link to the API Console is provided when you obtain a key.
To restrict the keys usage you will need to provide the package name and the SHA-1 signing certificate fingerprint from your keystore.
The SHA-1 certificate fingerprint is displayed in the file google_maps_api.xml.
Alternatively, the SHA-1 certificate fingerprint can be obtained by running the following command on the keystore:
keytool -list -v -keystore debug.keystore
debug.keystore is the name of the default keystore, usually
in directory C:\Users\username\.android (password is android)
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11. Test the Application Note: By default the Google Maps
Activity does not
contain an app bar.
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12. Map UI Properties
Similar to other Android UI properties, most map UI properties can be set using one of two approaches
declarative (in an XML file)
procedural approach (in the Java code).
As usual, the declarative approach is generally preferred.
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13. Classes MapFragment and SupportMapFragment
Classes MapFragment and SupportMapFragment (in package com.google.android.gms.maps) are the simplest ways to place a map in an application.
Use SupportMapFragment if you need to support Android devices running API 10 and lower.
These classes wrap a view of a map that automatically handles the necessary life cycle needs.
Add a MapFragment or a SupportMapFragment to an activity’s layout file. (This is done for you if you create a Google maps activity in Android Studio.)
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14. Selected XML Attributes for a MapFragment
mapType
values include none, normal, hybrid, satellite, and terrain
uiZoomControls, uiCompass
specify whether you want the zoom controls and compass to appear on the map
uiZoomGestures, uiScrollGestures, etc.
specify which gestures are enabled/disabled
liteMode
map that supports a subset of the map functionality
Add these attributes using the following namespace declaration:
xmlns:map="
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15. SupportMapFragment Example
<fragment xmlns:android=" xmlns:map=" xmlns:tools=" android:name="com.google.android.gms.maps.SupportMapFragment" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="edu.citadel.android.googlemaps.MapsActivity" map:uiCompass="true" map:uiZoomControls="true"/>
Note: This map fragment includes zoom controls and a compass.
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16. Class GoogleMap GoogleMap models the map object within an application.
GoogleMap automatically handles
Connecting to the Google Maps service.
Downloading map tiles.
Displaying tiles on the device screen.
Displaying various controls such as pan and zoom.
Responding to pan and zoom gestures by moving the map and zooming in or out.
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17. The OnMapReadyCallback Interface
The OnMapReadyCallBack interface contains a single abstract method.
public void onMapReady(GoogleMap googleMap)
Implement the OnMapReadyCallback interface to get access to a GoogleMap object.
Use the GoogleMap object to set map properties.
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18. Implementing the OnMapReadyCallback Interface
Import the necessary map classes and interfaces.
import com.google.android.gms.maps.*;
import com.google.android.gms.maps.model.*;
Declare that the activity implement the interface.
public class MainActivity extends AppCompatActivity
implements OnMapReadyCallback {
// set to true if permission is granted
private boolean isAccessLocationGranted = false;
private GoogleMap mMap;
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19. Implementing the OnMapReadyCallback Interface (continued)
Use getMapAsync() to set the callback on the map fragment.
@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);
checkAccessLocationPermission(); }
Or use class SupportMapFragment and
method getSupportFragmentManager()
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20. Implementing the OnMapReadyCallback Interface (continued)
Implement the onMapReady() method.
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Charleston and move the camera
LatLng charleston = new LatLng(32.781, );
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom
(charleston, 14));
if (isAccessLocationGranted)
try
mMap.setMyLocationEnabled(true); }
(continued on next slide)
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21. Implementing the OnMapReadyCallback Interface (continued)
catch (SecurityException ex) { String errorMsg = getString(R.string.no_permission); Log.e(LOG_TAG, errorMsg, ex); } mMap.addMarker(new MarkerOptions() .title("Charleston, S.C.") .snippet("The most beautiful city in North America.") .position(charleston));
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22. Requesting User Permissions
In order to call map.setMyLocationEnabled(true), user permission to access the user’s location must be declared in the Android manifest file and requested at runtime.
Example
<manifest ... >   <uses-permission
android:name="android.permission.ACCESS_FINE_LOCATION"/>     ... </manifest>
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23. Google Map Example (continued)
Moves map to
current location.
Using two fingers to
rotate the map will
enable the compass.
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24. Creating a Virtual Device for Google Maps
Make sure that Google Play Services and the Google Repository are installed as described earlier
Make sure that the virtual device target supports Google APIs; i.e., the phrase “Google APIs” should appear somewhere in the target name.
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25. Creating a Virtual Device for Google Maps (continued)
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26. Relevant Links Getting Started Google Maps Android API
Google Maps Android API
Set Up Google Play Services
Map Objects
Sign Your App
Google Maps Sample Project
<android-sdk>/extras/google/google_play_services/samples/maps
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