Using J2ME to create Field Force Applications

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Using J2ME to create Field Force Applications

• Chris Clark, MobileHWY, LLC

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THE BUSINESS
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The Mobility Business

• Building wireless applications that people can
  use everyday to get their job done.
• Using cheap or existing hardware. 200 or less
• Providing access to legacy data in a mobile
  environment
• Using the Internet to get data to and from the
  mobile devices. 50/mth or less.
• Leveraging GPS and Bluetooth to make the devices
  more capable.

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What do customers want?
Legacy Integration Integrating with backend
systems to make data available to mobile
applications. GPS Tracking of people, places
and things using GPS coordinates. Credit Card
Processing Creating mobile POS. Printing
Bluetooth printing capability for
receipts. Broadcast Messaging Sending broadcast
messages to mobile devices. Bluetooth Camera To
take pictures Bluetooth Compass To not only
determine location but direction you are facing.
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Mobile Building Blocks

• Legacy Integration
• - Database access SQL Server, Oracle, mySQL,
  Btrieve, Foxpro, ASCII Flat file
• Mainframe screen scraping Navigating 3270
  screens.
• Web screen scraping Automation of web sites.
• TCP Socket communication to host process.
• VoiceXML To automate Interactive Voice Response
  systems.

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Mobile Building Blocks

• GPS Global Positioning System
• Location tracking Reading GPS coordinates from
  mobile device.
• Driving Directions Get directions from where
  you are to where you need to go.
• Route Navigation Use GPS updates from the
  device to determine if route is being followed.
  Also can track speed and heading.
• Dynamic mapping of field force plot all data
  points for last known location of devices.
• Proximity searching search for locations near
  your current position. i.e. Location Based
  Services (LBS)

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Mobile Building Blocks
Credit Card Processing Using Bluetooth a mobile
device can attach to a credit card swipe
reader. All credit cards conform to the same
specification for storing credit card information
on Track 1. /1/Bltcreditcardnumbergtltlastnamegt/ltfi
rstnamegtltexpiration yeargtltexpiration
monthgtltotherdigitsgtCRLF If you can read one, you
can read them all.
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Mobile Building Blocks

• Printing
• Customers want to print a variety of information.
  
• Printing on a mobile device involves using serial
  IO to connect to the printer.
• Then sending printer Esc codes to the printer to
  format the information for display.
• There are 2 flavors of serial printing.
• - Bluetooth printing (uses Bluetooth serial
  profile)
• Tethered serial cable printing

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Mobile Building Blocks
Broadcast Messaging Customers have a high demand
for being able to send out broadcast messages to
their field force. Broadcast messaging uses a
queuing server which contacts each device
seperately and confirms delivery of the
message. Primarly socket communications to the
devices IP address from a centralized server.
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THE TECHNOLOGY
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Mobile Development
RULE 1 Using the device simulator is no
indication of how the application is going to run
on the device. RULE 2 Development tools are not
all the same. RULE 3 You are breaking new
ground. There will be issues that will require
trial and failure ?
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Several Things to Consider

• BUILD
• - Always build for optimal performance. Its not
  a PC.
• - There will be code differences needed sometimes
  for different devices. Some java will not pass
  bytecode verification on the device.
• TEST
• Know your carrier requirements for testing.
• Make sure you test on the device.
• DEPLOY
• - Find out early how you get your application on
  the device

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Getting Some Build Tools
Sun Microsystems Wireless Toolkit
2.2 http//java.sun.com/products/j2mewtoolkit/ Bla
ckberry Java Development Environment www.blackberr
y.com/developers Motorola iDen developer http//id
enphones.motorola.com/idenDeveloper/ EclipseME
J2ME plugin for Eclipse http//eclipseme.sourcefor
ge.net/
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It all starts with the MIDLET
public class CreditCardDemo extends MIDlet
public Display display /
Signals the MIDlet to start and enter the
Active state. / protected void
startApp() display
Display.getDisplay(this)
scrnCreditCard CreditCardForm new
scrnCreditCard(this)
CreditCardForm.Show() /
Signals the MIDlet to terminate and enter
the Destroyed state. / protected
void destroyApp(boolean unconditional)
notifyDestroyed() /
Signals the MIDlet to stop and enter the
Paused state. / protected void
pauseApp() / Do Nothing / public
void Show(Displayable d)
this.display.setCurrent(d)
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Understanding startApp()
Applications will suspend sometimes because of
incoming phone calls. startApp() will be called
again when this happens, so make sure you restore
to the proper screen. Dont assume that every
time startApp is called you should
login. Normally, I keep a public variable around
called display as part of the midlet class. I
initialize display to a value when the
application first starts. I check the value and
restore to the proper state. Here is a modified
startApp() protected void startApp()
if(display ! null) / Do nothing, will
restore the screen they were on / else
display Display.getDisplay(this)
scrnCreditCard CreditCardForm new
scrnCreditCard(this)
CreditCardForm.Show()
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Creating your screens
Creating screens are pretty straight forward.
You need a reference to the MIDlets display
object. Display display Display.getDisplay(MIDle
t m) With this display object you can change
the screen by calling setCurrent.
display.setCurrent(Displayable display)
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Creating your screens
There are 2 Displayable objects Screen
Displayable Screen is what you should think about
when you are designing form based applications.
This is primarily what we use. Canvas
Displayable Canvas is more centered toward games
or custom controls. With Canvas also comes the
ability to read the devices keyboard through
events. This is really designed more toward
games.
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Creating your screens
There are 4 types of objects you can use with
setCurrent() Form Screen You insert Items
onto the Form using Form.append or
Form.insert Alert Screen Alerts are similar to
VB message box. They provide quick notifications
as to what the application is doing. As with
message box there are different types of Alerts
(Alarm, Confirmation, Error, Info,
Warning). TextBox Screen A textbox is similar
to HTML lttextareagt. This is for multi-line text
entry. List Screen A list is for displaying a
list of choices. Lists can contain images.
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Creating your screens
There are several Items you can add to your
Form. ChoiceGroup Item Similar to List except
in a Form. DateField Item For presenting
calendar (date and time) information. Gauge
Item Bar graph ImageItem Item Add
image StringItem Item Add string TextField
Item Input text box with optional formatting
constraints.
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Processing Commands
Your class needs to support the CommandListener
interface public class scrnCreditCard implements
CommandListener You need to define the
command private static Command CMD_EXIT new
Command("EXIT", Command.ITEM, 1) You need to
implement the CommandListener interface public
void commandAction(Command c, Displayable d)
if (c CMD_EXIT)
app.destroyApp(true)
If you intend to access your Forms Items
within the commandAction, you need to define your
Item at the class level. private StringItem
progressLabel
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Data Storage
javax.microedition.rms.RecordStore Record
Management System J2ME provides a really basic
storage capability for storing strings called a
RecordStore. A database is a stretch. Think of
being able to store strings in a file and
retrieve them based on a record ID. In practical
use, we create ENTITY CLASSES that are capable of
going to and from strings. We create a class
with all its properties and provide - parse()
method for retrieving the state of the object
from a string. - toString() method for storing
the state of the object to a string. Using this
capability, we are able to effectively retrieve
objects from the RecordStore and return them to
their state.
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Data Storage
SELECT public void getRecord( int recordId
) INSERT public int RecordStore.addRecord(
byte data, int offset, int numBytes )
UPDATE public void setRecord( int recordId,
byte newData, int offset, int numBytes
) DELETE public void deleteRecord( int recordId
)
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HTTP
StringBuffer text new StringBuffer() HttpConne
ction c (HttpConnection) Connector.open(getUrl,
Connector.READ_WRITE, true) c.setRequestMethod(
HttpConnection.GET) int rc c.getResponseCode()
if (rc HttpConnection.HTTP_OK)
InputStream is c.openDataInputStream() int
ch while((ch is.read()) ! -1)
text.append((char) ch) else throw
new IOException("HTTP response code "
rc) String response text.toString()
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Entity Classes
We heavily use ENTITY CLASSES for the data
operations in the mobile device. After
retrieving data through some method of
HTTP. Create a new instance of your ENTITY
CLASS Set the properties of the ENTITY CLASS
from the data you have retrieved through HTTP. A
simple method maybe to parse through some
XML. After you have the state of your ENTITY
CLASS. Convert this state to a string by calling
the toString() method. Store this string in your
RecordStore using RecordStore.add()
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GPS
GPS support is going to be dependant on device.
JSR129 or MAYBE NOT JSR129 EXAMPLE try
// Lots of Criteria options are available per
spec, few supported Criteria myCriteria
new Criteria() LocationProvider
myLocProv LocationProvider.getInstance(myCriteri
a) // If no result could be retrieved,
a LocationException is thrown. Location
myLocation myLocProv.getLocation(-1)
// returns a QualifiedCoordinates object which
also has accuracy information // inherits
from Coordinates object
QualifiedCoordinates myCoordinates
myLocation.getQualifiedCoordinates() //
get the Coordinates from the QualifiedCoordinates
double myLat myCoordinates.getLatitude()
double myLng myCoordinates.getLongitud
e() catch (LocationException locex)
// Could not get a fix
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GPS Mapping
Once you have the coordinates of the device. Most
of the GPS features are implemented using other
services. A dynamic mapping example. Tracking
the device may require you to send the
coordinates to a centralized server and time and
date stamp them into a database. A web based
system may retrieve the coordinates and display
them to the user on a map. Lot of technologies
may be in play here with the mobile device being
the most simple of the technologies
employed. Mapping Strategies Automation of
MapPoint to create custom .NET Web
services Using Microsoft MapPoint Web
Services Using MapQuest Web Services
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J2ME Connector
Whether you are doing serial printing using a
tethered cable to the device or Bluetooth. The
process is pretty much the same. J2ME offers a
Connector architecture for communications. Serial
communications is just about the same as HTTP
except for the ConnectionString. If you know how
to work with Streams in J2ME you can communicate
to most anything. In serial communication, you
are primarily dealing with COM0. String
connstring "comm0baudrate19200parityndatab
its8stopbits1flowcontrols/s" Bluetooth
varies and most connection strings appear to be
proprietary based on the hardware. In some cases
the connection string is even abstracted through
classes as you will see in the next example.
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J2ME Connector
String connstring "comm0baudrate19200parity
ndatabits8stopbits1flowcontrols/s"
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Bluetooth Serial Printing
BluetoothSerialPortInfo info
BluetoothSerialPort.getSerialPortInfo() // Get
first Bluetooth Serial Device registered with
this mobile device String bluetoothConnectionStrin
g info0.toString() StreamConnection sc
(StreamConnection) Connector.open(bluetoothConnect
ionString, Connector.READ_WRITE) DataOutputStrea
m outstream sc.openDataOutputStream() outstrea
m.write(this.data.getBytes()) outstream.flush()
outstream.close() sc.close()