MIDP Programming - Java 2 Micro Edition Application Development - page 50

teleTransfer.back();
}
}
}
Figure 3.8 shows the TransferReason TextBox .
Figure 3.8. The TransferReason TextBox showing a sample transfer reason text.
TeleTransfer with Multiple Screens
Now you have created two additional screens, but you still need to integrate them in your main
application. To do so, you need to change the TeleTransfer implementation somewhat. Since the
TeleTransfer 's ChoiceGroup for selecting the currency is replaced by the CurrencyList ,
you do not need the ItemStateListener for detecting item changes any more. So you remove the
listener and also the corresponding callback method itemStateChanged() . To display the two
new Screen s CurrencyList and TransferReason , you implement the two commands
currencyCommand and reasonCommand . The new commands are added to the MIDlet in the
constructor using the addCommand() method. In the clear() method, the new TextBox is also
cleared by calling the corresponding setString() method. Finally you add the back() method to
the TeleTransfer application; this method is called from the new Screen s to return to the main
form. The commandAction() method is extended to handle the new commands, displaying the new
Screen s. Listing 3.1 shows the complete source code of the final version of the TeleTransfer
application.
Listing 3.1 TeleTransfer.java —The Complete TeleTransfer Sample Source Code
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
class CurrencyList extends List implements CommandListener {
TeleTransfer teleTransfer;
static final String [] CURRENCY_NAMES = {"Dollar", "Euro",
"Yen"} ;
static final String [] CURRENCY_FRACTIONS = {"Cent", "Cent",
"Sen"} ;
public CurrencyList (TeleTransfer teletransfer) {
super ("Select Currency", Choice.IMPLICIT);
this.teleTransfer = teletransfer;
try {
append ("USD", Image.createImage ("/Dollar.png"));
append ("EUR", Image.createImage ("/Euro.png"));
append ("JPY", Image.createImage ("/Yen.png"));
}