1. Chapter 11: Discover! Incorporating Google Maps

2. Objectives In this chapter, you learn to:
Create an Android project displaying a Google map
Install the Google API to the SDK
Set up a Google API Android Virtual Device
Locate your MD5 certificate
Sign up for a Google Maps API key
Understand security and permissions
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3. Objectives (continued)
Access the MapView class
Code the populate( ) method
Add the onTap( ) method
Set permissions for maps in the Android Manifest file
Create a GeoPoint overlay
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4. Using Google Maps
Smartphones can access online maps using a built-in Android Google Maps application
Users can zoom in to see details
Can be customized
Figure 11-1 Maps Application
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5. Using Google Maps (continued)
Steps to complete the App:
Install the Google API add-on to the SDK.
Add the AVD that uses the Google API deployment target.
Obtain a personal Maps API key from Google.
Define a MapView inside a Linear layout in main.xml.
Add permissions to the Android Manifest file to access the Internet and the Google library.
Add a no title bar theme to the Android Manifest file.
Add the pushpin image to the drawable folder.
Code the MapView in Main.java.
Add Overlay objects to the map.
Call the populate( ) method to read each Overlay object.
Display two GeoPoint overlays.
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6. Using Google Maps (continued)
Google Maps is a Free online mapping service offering things like:
Turn-by-turn directions
GPS Location Services
Directions to a hotel
Distance of a morning run
Street view images
Bike path directions
Possible Traffic delays
Public transit routes
Began in the United States in 2005
Updated Frequently
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7. Installing the Google API
API – Application Programming Interface
A set of tools for building software applications
Downloading, rendering, and caching of map files
Must be downloaded and installed in your SDK environment
Figure 11-3 Android SDK Manager
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8. Installing the Google API (continued)
Adding the AVD to Target the Google API
Android Virtual Device (AVD) must be set to use the Google API
Figure 11-4 Android Virtual device Manager dialog box
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9. Installing the Google API (continued)
Figure 11-6 Google API displayed in the AVD list
Figure 11-5 Create new Android Virtual Device (AVD) dialog box
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10. Obtaining a Maps API Key from Google
Must apply for a free Google Maps API key
Register and agree to terms with Google Maps Service
Your computer’s MD5 (Message-Digest Algorithm 5) digital fingerprint verifies the integrity of the file
A unique Google Maps API key is generated:
Certificate fingerprint (MD5): 94:1E:43:49:87:73:BB:E6:A6:88:D7:20:F1:8E:B5:98
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11. Obtaining a Maps API Key from Google (continued)
You cannot run a Google Map app if it is not signed with your local API key.
Key is stored in a file named debug.keystore
Figure 11-7 Location of the debug.keystore file on a Windows 7 computer
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12. Obtaining a Maps API Key from Google (continued)
Figure 11-8 MD5 fingerprint in the Command Prompt window
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13. Obtaining a Maps API Key from Google (continued)
Troubleshooting:
Keytool not recognized
You need to locate the keytool executable file on your computer
A fingerprint other than MD5 is generated
A fingerprint such as SHA1 might appear instead of the MD5 fingerprint
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14. Obtaining a Maps API Key from Google (continued)
Registering the MD5 Fingerprint with the Google Maps Service
A single Maps API key is valid for all applications signed by a single certificate
Place theMD5 fingerprint in the Google Registration page
You need a Gmail account to receive the API key
Place the API key in the XML layout code
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15. Obtaining a Maps API Key from Google (continued)
Figure Android Maps API Key Signup Web Site
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16. Obtaining a Maps API Key from Google (continued)
Figure Unique MD5 fingerprint code
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17. Obtaining a Maps API Key from Google (continued)
Figure Android Maps API key
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18. Obtaining a Maps API Key from Google (continued)
Adding the MapView element in the XML Code
API key attribute holds the Google Maps API key that proves your application and signed certificate are registered with the Google Maps service
the API key must be added to the main.xml layout file
You must use the <com.google.android.maps.MapView/> element to display the Google Maps in your Activity
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19. Obtaining a Maps API Key from Google (continued)
<com.google.android.maps.MapView
+id/mapview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:enabled="true"
android:clickable="true"
android:apiKey="0HljqLj_jO8oBj4g8zSxyEuezie5-mE_56_UiXA“
/>
Note: Your generated apiKey will be different.
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20. Obtaining a Maps API Key from Google (continued)
Adding Permissions to the Android Manifest File
Permissions are necessary to prevent malicious outside applications from corrupting data and accessing sensitive information including:
Full access to the Internet
Your GPS location
Your personal information
Phone calls
SMS Messages
Other system tools
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21. Obtaining a Maps API Key from Google (continued)
Figure Android Manifest code with the Google library permission
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22. Understanding MapView
The MapView class displays and manipulates a Google Map
The setBuiltInZoomControls property allows the site visitor to use the built-in zoom feature
MapView mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
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23. Understanding MapView (continued)
Figure Main Extends MapActivity
Figure Instance of MapView and the zoom controls set to true
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24. Understanding MapView (continued)
Figure Google Maps displayed in the Android emulator
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25. Adding Overlay Items
Overlays – also called Map markers – use a graphic image to indicate a specific location on a map
Use the ItemizedOverlay class to manage the individual items placed as a layer on the map
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26. Adding Overlay Items (continued)
Figure Overlay.java class
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27. Adding Overlay Items (continued)
Figure Overlay.java class automated code
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28. Adding Overlay Items (continued)
Adding Overlay Objects to an ArrayList
Assign an expandable array called ArrayList
Customized constructors needed to define default markers
Populate() method used to add each pushpin item to the display
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29. Adding Overlay Items (continued)
private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
private Context mContext;
public Overlay(Drawable defaultMarker, Context context) {
super(boundCenterBottom(defaultMarker));
mContext = context;
// TODO Auto-generated constructor stub }
public void addOverlay(OverlayItem overlay) {
mOverlays.add(overlay);
populate();
@Override
protected OverlayItem createItem(int i) {
// TODO Auto-generated method stub
return mOverlays.get(i);
public int size() {
return mOverlays.size();
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30. Adding Overlay Items (continued)
Figure Overlay constructor
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31. Adding Overlay Items (continued)
Figure The addOverlay method populates the pushpin images
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32. Adding Overlay Items (continued)
Figure OverlayItem method
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33. Adding Overlay Items (continued)
Coding the onTap Method
onTap() method receives the index of the overlay item selected by the user
The AlertDialog box displays a message to the user
The show() method is actually used to display the dialog box
@Override
protected boolean onTap(int index) {
OverlayItem item = mOverlays.get(index);
AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
dialog.setTitle(item.getTitle());
dialog.setMessage(item.getSnippet());
dialog.show();
return true; }
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34. Adding Overlay Items (continued)
Figure onTap() method
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35. Adding Overlay Items (continued)
Figure Instance named item and the AlertDialog box are coded
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36. Adding Overlay Items (continued)
Figure Complete code of Overlay.java
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37. Adding Overlay Items (continued)
Coding the Drawable Overlay
Figure List of Overlay items
Figure The pushpin image becomes the map marker
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38. Locating a GeoPoint Default Google map is of the United States
Any worldwide location can be found by panning and zooming
Map location – called the GeoPoint – contains latitude and longitude coordinates
GeoPoint locations are in microdegrees (degrees * 1e6)
For example, Lynchburg Virginia’s latitude and longitude coordinates are °, °, which yields coordinates of , microdegrees
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39. Locating a GeoPoint (continued)
Coding the GeoPoint Location
Figure First GeoPoint
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40. Locating a GeoPoint (continued)
Figure Second GeoPoint
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41. Locating a GeoPoint (continued)
Figure Main.java complete code
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42. Summary
To use Google Maps, you must install the Google API (application programming interface) in the Android SDK and then embed the Google Maps site directly into an Android application and overlay app-specific data on the map
Set the application’s properties to select the Google APIs add-on as the build target, which sets the Android Virtual Device (AVD) Manager to use the new Google API
You need to apply for a free Google Maps API key to integrate Google Maps into your Android application
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43. Summary (continued)
Using the MD5 fingerprint, you can register with Google for aMaps API key at the onlineGoogleMaps service. To display a Googlemap in an Android app, you must add the API key to the main.xml layout file in your project
You must use the <com.google.android.maps.MapView> element to display the Google Maps in your Activity
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44. Summary (continued)
Android apps use permissions to prevent malicious outside applications from corrupting data and accessing sensitive information. Apps need permission to access the Internet and connect with the Google mapping feature
Google mapping technology relies on the Android MapView class
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45. Summary (continued)
An instance of MapView uses the setBuiltInZoomControls property. When set to true, this property allows site visitors to use the built-in zoom feature on the map in your Android app
A map marker, or overlay, uses a graphic image such as a pushpin to indicate a specific location on a map
The Overlay class assigns an ArrayList to hold the overlay objects, such as pushpin images, displayed in a layer on the map
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46. Summary (continued)
Use the populate( ) method to add each new item in the ItemizedOverlay to the map
Use the onTap() method to display a text message
Use an instance of the MapView class to list points of interest
Users can pan and zoom to find any location in the world from the default USA map
GeoPoints contain latitude & longitude coordinates
Use the add( ) method to display the GeoPoints as an overlay on the map
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