Easy steps to develop android application (tutorial)

Android ApplicationAndroid Application
Development TutorialDevelopment Tutorial
Accessing Sensors and the Network
Deepa Shinde and Cindy Atherton

TopicsTopics
Background
Introduction to Android
Overview of Sensors
Programming Tutorial 1: Tracking location with
GPS and Google Maps
Overview of Networking
Programming Tutorial 2: Downloading from the
Internet
Programming Tutorial 3: Sending/Receiving SMS
Messages
Questions/Comments
Resources

Introduction to Android
A brief guide to the Android Application Development Environment

BackgroundBackground
Software platform from Google and the
Open Handset Alliance
July 2005, Google acquired Android, Inc.
November 2007, Open Handset Alliance
formed to develop open standards for
mobile devices
October 2008, Android available as open
source
December 2008, 14 new members joined
Android project

Update HistoryUpdate History
April 30, 2009: Official 1.5 Cupcake
release
September 15, 2009: 1.6 SDK Donut
release
October 26, 2009: 2.0 SDK Éclair release
◦ Updates to the Éclair release:
 2.0.1 on December 3, 2009
 2.1 on January 12, 2010

Platform VersionsPlatform Versions

Android and the HardwareAndroid and the Hardware
Built-in Apps Apps created in SDK≡
Leverage Linux kernel to interface with
hardware
Open source platform promotes
development from global community

Android FeaturesAndroid Features
Reuse and replacement of components
Dalvik virtual machine
Integrated browser
Optimized graphics
SQLite
Media support
GSM Telephony
Bluetooth, EDGE, 3G, and WiFi
Camera, GPS, compass, and accelerometer
Rich development environment

Android ArchitectureAndroid Architecture

Application FundamentalsApplication Fundamentals
Apps are written in Java
Bundled by Android Asset Packaging Tool
Every App runs its own Linux process
Each process has it’s own Java Virtual
Machine
Each App is assigned a unique Linux user
ID
Apps can share the same user ID to see
each other’s files

Application ComponentsApplication Components
 Activity
◦ Present a visual user interface for one focused endeavor the user can
undertake
◦ Example: a list of menu items users can choose from
 Services
◦ Run in the background for an indefinite period of time
◦ Example: calculate and provide the result to activities that need it
 Broadcast Receivers
◦ Receive and react to broadcast announcements
◦ Example: announcements that the time zone has changed
 Content Providers
◦ Store and retrieve data and make it accessible to all applications
◦ Example: Android ships with a number of content providers for common
data types (e.g., audio, video, images, personal contact information, etc.)
 Intents
◦ Hold the content of a message
◦ Example: convey a request for an activity to present an image to the user
or let the user edit some text

InstallationInstallation
http://developer.android.com/sdk/installing.html
Preparing your system and system
requirements
Downloading and Installing the SDK
Installing ADT plug-in for Eclipse
Adding Platforms and Components
Exploring the SDK
Completing tutorials
Troubleshooting

Overview of Sensors
The Android Sensor Platform and how to use it

Open Source PlatformOpen Source Platform
Developer’s are able to access “goodies”
Hardware capabilities made available

Hardware-oriented FeaturesHardware-oriented Features
Feature Description
Camera
A class that enables your application to interact with the camera to snap a photo, acquire images
for a preview screen, and modify parameters used to govern how the camera operates.
Sensor Class representing a sensor. Use getSensorList(int) to get the list of available Sensors.
SensorManager A class that permits access to the sensors available within the Android platform.
SensorEventListener
An interface used for receiving notifications from the SensorManager when sensor values have
changed. An application implements this interface to monitor one or more sensors available in the
hardware.
SensorEvent
This class represents a sensor event and holds information such as the sensor type (e.g.,
accelerometer, orientation, etc.), the time-stamp, accuracy and of course the sensor's data.
MediaRecorder
A class, used to record media samples, that can be useful for recording audio activity within a
specific location (such as a baby nursery). Audio clippings can also be analyzed for identification
purposes in an access-control or security application. For example, it could be helpful to open the
door to your time-share with your voice, rather than having to meet with the realtor to get a key.
GeomagneticField
This class is used to estimated estimate magnetic field at a given point on Earth, and in particular,
to compute the magnetic declination from true north.
FaceDetector
A class that permits basic recognition of a person's face as contained in a bitmap. Using this as a
device lock means no more passwords to remember — biometrics capability on a cell phone.

Sensor and SensorManagerSensor and SensorManager
Sensor type (Sensor class)
◦ Orientation, accelerometer, light, magnetic field,
proximity, temperature, etc.
Sampling rate
◦ Fastest, game, normal, user interface.
◦ When an application requests a specific sampling
rate, it is really only a hint, or suggestion, to the
sensor subsystem. There is no guarantee of a
particular rate being available.
Accuracy
◦ High, low, medium, unreliable.

Programming Tutorial
Simulating an Android application that accesses positioning sensors

Preparing for the TutorialPreparing for the Tutorial
Must have Eclipse IDE installed
Must have Android SDK installed
Must have knowledge of Java
Must have the external Google Maps
library installed in your SDK environment.
The Maps library is included with the
Google APIs add-on, which you can install
using the Android SDK and AVD Manager.

Get a Google Maps API KeyGet a Google Maps API Key
 A Google Maps API key is required to integrate Google Maps into your Android
application.
 To apply for a key:
1. Locate the SDK debug certificate in the default folder of "C:Documents and
Settings<username>Local SettingsApplication DataAndroid". The filename of the
debug keystore is debug.keystore.
2. Copy the debug.keystore file to a folder named C:Android.
3. Open the command window and navigate to C:Program
FilesJava<JDK_version_number>bin to locate the Keytool.exe.
4. Execute the following to extract the MD5 fingerprint:
keytool.exe -list -alias androiddebugkey -keystore "C:Androiddebug.keystore" -storepass
android -keypass android
1. Copy the MD5 certificate fingerprint and navigate your web browser to:
http://code.google.com/android/maps-api-signup.html.
2. Follow the instructions on the page to complete the application and obtain the
Google Maps key.
For more information on using Google Maps in Android application development:
http://mobiforge.com/developing/story/using-google-maps-android

Create an Android Virtual Device (AVD)Create an Android Virtual Device (AVD)
Defines the system image and device
settings used by the Emulator
To create an AVD in Eclipse:
1. Select Window > Android SDK and AVD Manager.
The Android SDK and AVD Manager displays.
1. Make sure the entry for Virtual Devices is selected
and click New.
The Create new AVD window displays.
1. Enter a Name for the AVD.
2. Select Google APIs (API level 3) as the Target.
3. Click Create AVD.
4. Close the Android SDK and AVD Manager.

Create the Android ProjectCreate the Android Project
To create the project in Eclipse:
1. Select File > New > Project.
2. Select Android Project in the Android folder and
click Next.
3. Enter GPSSimulator as the Project Name.
4. Select Google APIs (Platform 1.5) as the Build
Target.
5. Enter GPSSimulator as the Application name.
6. Enter com.android.gpssimulator as the Package
name.
7. Enter GPSSimulator as the Activity name.
8. Click Finish.

The New Android ProjectThe New Android Project

Modify the AndroidManifest.xml FileModify the AndroidManifest.xml File
Add permissions for GPS
To modify the AndroidManifest.xml file:
1. Click on the res folder in the GPSSimulator
project.
2. Double-click AndroidManifest.xml to display the
GPSSimulator Manifest.
3. Enter the following lines before the application
tag.
<uses-permission
android:name=“android.permission.ACCESS_FINE_LOCATION” />
1. Save the changes to the file.

Add LocationManager to getAdd LocationManager to get
UpdatesUpdates
public class GPSSimulator extends Activity
{
private LocationManager lm;
private LocationListener locationListener;
// Called when the activity is first created.
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// use the LocationManager class to obtain GPS locations
lm = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);
locationListener = new MyLocationListener();
lm.requestLocationUpdates(
LocationManager.GPS_PROVIDER, 0, 0, locationListener);
}
}

Add MyLocationListenerAdd MyLocationListener
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
if (loc != null) {
Toast.makeText(getBaseContext(),
"Location changed : Lat: " + loc.getLatitude() +
" Lng: " + loc.getLongitude(),
Toast.LENGTH_SHORT).show();
}
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}

Test the GPSSimulatorTest the GPSSimulator
To test in Eclipse:
1. Switch to DDMS view.
2. Find the Location Controls in the Emulator
Control tab.
3. Click the GPX tab and click Load GPX.
4. Locate and select the GPX file.
5. Click Play to begin sending coordinates to the
Emulator.

Add ability to use Google MapsAdd ability to use Google Maps
Update the Manifest with two lines.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.GPSSimulator">
<uses-permission
android:name="android.permission.INTERNET" />
<uses-permission
android:name="android.permission.ACCESS_FINE_LOCATION" />
<application android:icon="@drawable/icon"
android:label="@string/app_name">
<uses-library android:name="com.google.android.maps" />
<activity android:name=".GPS" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

Add MapView to main.xmlAdd MapView to main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<com.google.android.maps.MapView
android:id="@+id/mapview1"
android:enabled="true"
android:clickable="true"
android:apiKey=“Your API Key Here" />
</LinearLayout>

Modify GPSSimulator to useModify GPSSimulator to use
Google MapsGoogle Maps
public class GPSSimulator extends MapActivity {
private LocationManager lm;
private LocationListener locationListener;
private MapView mapView;
private MapController mc;
// Called when the activity is first created.
@Override
// use the LocationManager class to obtain GPS locations
lm = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);
locationListener = new MyLocationListener();
lm.requestLocationUpdates(
LocationManager.GPS_PROVIDER, 0, 0, locationListener);
mapView = (MapView) findViewById(R.id.mapview1);
mc = mapView.getController();
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
if (loc != null) {
"Location changed : Lat: " + loc.getLatitude() +
" Lng: " + loc.getLongitude(),
GeoPoint p = new GeoPoint(
(int) (loc.getLatitude() * 1E6),
(int) (loc.getLongitude() * 1E6));
mc.animateTo(p);
mc.setZoom(16);
mapView.invalidate();
}
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}
}

View the Location on the MapView the Location on the Map

Internet LayersInternet Layers
 The Internet, is based on a
layered architecture called
the TCP/IP stack.
 Link Layer
◦ Protocols: ARP and RARP
 Internet Layer
◦ Protocols: IP, ping, etc.
 Transport
◦ Protocols: TCP and UDP
 Application Layer
◦ Protocols: HTTP, FTP, DNS, etc.

Client-Server Communication
A server machine is identified on the Internet by
some IP address
Daemons are the processes running in the
background which are listening all the time for
connection requests from clients on a particular
port number.
Once a connection request comes into the server
on a given port, the corresponding daemon can
choose to accept it, and if so, a connection is
established.
Then the application layer protocol is typically used
for the client to get or send data to the server.

Programming Tutorial 2
Accessing a website from the Android Emulator

Link Activity and ViewLink Activity and View
View object may have an integer ID associated
with it
android:id="@+id/my_button“
To get the reference of the view object in activity
Button myButton =
(Button)findViewById(R.id.my_button);

Adding Event to View ObjectAdding Event to View Object
View.OnClickListener()
◦ Interface definition for a callback to be invoked
when a view is clicked.
onClick(View v)
◦ Called when a view has been clicked. Inside
this function you can specify what actions to
perform on a click.

AndroidManifest.xmlAndroidManifest.xml

Network SettingsNetwork Settings
If you are using the emulator then there are
limitations. Each instance of the emulator
runs behind a virtual router/firewall service
that isolates it from your development
machine's network interfaces and settings
and from the internet.
Communication with the emulated device
may be blocked by a firewall program running
on your machine.
Reference

Behind Proxy ServerBehind Proxy Server

App to Download jpg fileApp to Download jpg file
Step1 Add permissions to AndroidManifest.xml
<uses-permission android:name="android.permission.INTERNET" />
Step 2 Import files
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

Step 3 Writing OpenHttpConnection()
◦ To open a connection to a HTTP server using OpenHttpConnection()
◦ We first create an instance of the URL class and initialize it with the URL
of the server
◦ When the connection is established, you pass this connection to an
URLConnection object. To check if the connection established is using a
HTTP protocol.
◦ The URLConnection object is then cast into an HttpURLConnection
object and you set the various properties of the HTTP connection.
◦ Next, you connect to the HTTP server and get a response from the
server. If the response code is HTTP_OK, you then get the InputStream
object from the connection so that you can begin to read incoming data
from the server
◦ The function then returns the InputStream object obtained.

public class HttpDownload extends Activity {
/** Called when the activity is first
created.*/
@Override
public void onCreate(Bundle
savedInstanceState) {
}
private InputStream OpenHttpConnection(String
urlString) throws IOException {
InputStream in = null;
int response = -1;
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
if (!(conn instanceof HttpURLConnection))
throw new IOException("Not an HTTP
connection");
try{
HttpURLConnection httpConn =
(HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestMethod("GET");
httpConn.connect();
response = httpConn.getResponseCode();
if (response == HttpURLConnection.HTTP_OK)
{
in = httpConn.getInputStream();
}
} catch (Exception ex) {
throw new IOException("Error
connecting");
}
return in;
}
}

 Step 4 Modify the Main.xml code
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
>
<ImageView
android:id="@+id/img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>
<TextView
android:id="@+id/text"
android:textStyle="bold"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>

 Step 5 writing
DownloadImage()
◦ The DownloadImage() function
takes in a string containing the
URL of the image to download.
◦ It then calls the
OpenHttpConnection() function
to obtain an InputStream object
for reading the image data.
◦ The InputStream object is sent
to the decodeStream() method
of the BitmapFactory class.
◦ The decodeStream() method
decodes an InputStream object
into a bitmap.
◦ The decoded bitmap is then
returned by the
DownloadImage() function.
private Bitmap DownloadImage(String URL) {
Bitmap bitmap = null;
InputStream in = null;
try {
in = OpenHttpConnection(URL);
bitmap = BitmapFactory.decodeStream(in);
in.close();
} catch (IOException e1) {
e1.printStackTrace();
}
return bitmap;
}

 Step 6 Test the DownloadImage() function, modify the
onCreate() event as follows
@Override
Bitmap bitmap = DownloadImage(
"http://www.streetcar.org/mim/cable/images/cable-01.jpg");
img = (ImageView) findViewById(R.id.img);
img.setImageBitmap(bitmap);
}

Step 7:Output

Programming Tutorial 3
Transmitting SMS messages across the network

Intent and IntentFilterIntent and IntentFilter
Intents request for an action to be
performed and supports interaction
among the Android components.
◦ For an activity it conveys a request to present
an image to the user
◦ For broadcast receivers, the Intent object
names the action being announced.
Intent Filter Registers Activities, Services
and Broadcast Receivers(as being capable
of performing an action on a set of data).

SMS SendingSMS Sending
 STEP 1
◦ In the
AndroidManifest.xml file,
add the two permissions -
SEND_SMS and
RECEIVE_SMS.
 STEP 2
◦ In the main.xml, add Text
view to display "Enter the
phone number of
recipient“ and "Message"
◦ EditText with id
txtPhoneNo and
txtMessage
◦ Add the button ID "Send
SMS“

• Step 3 Import Classes and Interfaces
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

 Step 4 Write the SMS class
public class SMS extends Activity {
Button btnSendSMS;
EditText txtPhoneNo;
EditText txtMessage;
/** Called when the activity is first created. */
@Override
btnSendSMS = (Button) findViewById(R.id.btnSendSMS);
txtPhoneNo = (EditText) findViewById(R.id.txtPhoneNo);
txtMessage = (EditText) findViewById(R.id.txtMessage);
btnSendSMS.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String phoneNo = txtPhoneNo.getText().toString();
String message = txtMessage.getText().toString();
if (phoneNo.length()>0 && message.length()>0)
sendSMS(phoneNo, message);
else
"Please enter both phone number and message.",
}
});
}
}
Input from the
user (i.e., the
phone no, text
message and
sendSMS is
implemented).

Step 5
◦ To send an SMS message, you use the
SmsManager class. And to instantiate this class
call getDefault() static method.
◦ The sendTextMessage() method sends the SMS
message with a PendingIntent.
◦ The PendingIntent object is used to identify a
target to invoke at a later time.
private void sendSMS(String phoneNumber, String message) {
PendingIntent pi = PendingIntent.getActivity(this, 0,
new Intent(this, SMS.class), 0);
SmsManager sms = SmsManager.getDefault();
sms.sendTextMessage(phoneNumber, null, message, pi, null);
}

Receiving SMSReceiving SMS
Step 1

Step 2
◦ In the AndroidManifest.xml file add the <receiver> element so
that incoming SMS messages can be intercepted by the
SmsReceiver class.
<receiver android:name=".SmsReceiver">
<intent-filter>
<action android:name=
"android.provider.Telephony.SMS_RECEIVED" />
</intent-filter>
</receiver>

Step 3
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.SmsMessage;

 Step 4
public class SmsReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
//---get the SMS message passed in---
Bundle bundle = intent.getExtras();
SmsMessage[] msgs = null;
String str = "";
if (bundle != null){
//---retrieve the SMS message received---
Object[] pdus = (Object[]) bundle.get("pdus");
msgs = new SmsMessage[pdus.length];
for (int i=0; i<msgs.length; i++) {
msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
str += "SMS from " + msgs[i].getOriginatingAddress();
str += " :";
str += msgs[i].getMessageBody().toString();
str += "n";
}
//---display the new SMS message---
Toast.makeText(context, str, Toast.LENGTH_SHORT).show();
}
}
}
In the SmsReceiver class,
extend the
BroadcastReceiver class
and override the
onReceive() method. The
message is attached to the
Intent
The messages are stored in a
object array PDU format. To
extract each message, you
use the static
createFromPdu() method from
the SmsMessage class. The
SMS message is then
displayed using the Toast
class

ConclusionsConclusions
What is Android?
What are the sensor and networking
capabilities in Android?
How to use location data and Google
maps in Android?
How to access websites?
How to send SMS messages across the
network?
Questions/Comments?

ResourcesResources
 Ableson, Frank. “Tapping into Android’s sensors.” www.ibm.com. January 30, 2010.
http://www.ibm.com/developerworks/opensource/library/os-android-sensor/index.html
 Ableson, Frank; Collins, Charlie; Sen, Robi. Unlocking Android, A Developer’s Guide.
Greenwich: Manning Publications Co. 2009.
 Android Development Guide. January 30, 2010.
http://developer.android.com/guide/index.html
 Lee, Wei-Meng. “Using Google Maps in Android.” mobiforge.com. January 30, 2010.
http://mobiforge.com/developing/story/using-google-maps-android
 Lee, Wei-Meng. “You Are Here: Using GPS and Google Maps in Android.” www.devx.com.
January 30, 2010. http://www.devx.com/wireless/Article/39239/1954
 Lee, Wei-Meng “SMS Messaging in Android” mobiforge.com. January 30, 2010
 http://mobiforge.com/developing/story/sms-messaging-android
 Lee, Wei-Meng “Connecting to the Web: I/O Programming in Android” November 5, 2008
Android”http://www.devx.com/wireless/Article/39810
 Open Handset Alliance, http://www.openhandsetalliance.com/
 Patterson, Don. “Android Development Guide.” getsatisfaction.com. January 30, 2010.
http://getsatisfaction.com/luci/topics/android_development_guide
 www.androidcompetencycenter.com. January 30, 2010.
http://www.androidcompetencycenter.com/2009/06/accessing-device-sensors
 Xianhua Shu; Zhenjun Du; Rong Chen, "Research on Mobile Location Service Design Based
on Android," Wireless Communications, Networking and Mobile Computing, 2009. WiCom
'09. 5th International Conference on , vol., no., pp.1-4, 24-26 Sept. 2009
http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=5302615&isnumber=5300799

Easy steps to develop android application (tutorial)

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