Senthilkumar Shanmugam

Handling LOVs in Mobile Applications

In this article, we will see how to handle LOV bean in MWA.
In this example, we will create an LOV which displays the list of users from fnd_user ptable starting with ‘S’.
You can use these code snippets and make changes to the Hello world Sample Program which was published earlier and test it out.
The following are the steps to be performed.

Step 1:

In CustomTestPage.java, declare the variable for LOV, set properties like prompt, ID, Listener and add a handler method to the LOV

LOVFieldBean mUserNames;
mUserNames = new LOVFieldBean();
mUserNames.setName("TEST.LOV");
mUserNames.setPrompt("User LOV");

addFieldBean(mUserNames);
mUserNames.addListener(fieldListener);

public LOVFieldBean getUserLOV()
{
return mUserNames;
}

Please note that the handler method will be used in Listener Class to get handle of the bean.

Step 2:

Getting the List of Values for LOV. As we know LOV is nothing but a result set of a query. This result set can be attached to the LOV by 2 ways.

1. By SQL Query.

2. By a PLSQL package which executes the query and gives the result set as OUT parameter (via REF CURSOR)

In this example, we are going to use the following PLSQL package. This package basically gets all the users from FND_USER starting with the alphabet provided as a input parameter. The Code is as follows:

create or replace package XXX_MWA_LOV_TEST AS
    TYPE t_ref_csr IS REF CURSOR;
    PROCEDURE XXX_USERS_LOV (x_users OUT NOCOPY t_ref_csr
    ,p_user_name IN VARCHAR2);
end XXX_MWA_LOV_TEST;



create or replace package body XXX_MWA_LOV_TEST AS
PROCEDURE XXX_USERS_LOV (x_users OUT NOCOPY t_ref_csr
,p_user_name IN VARCHAR2
)

IS
BEGIN
OPEN x_users FOR
select user_id,user_name,description
from fnd_user
where user_name like p_user_name;

EXCEPTION
WHEN OTHERS THEN
    DBMS_OUTPUT.PUT_LINE('ERROR IN USER LOV '|| SQLERRM);
END XXX_USERS_LOV;

end XXX_MWA_LOV_TEST;

Step 3:

In CustomTestListener.java, as we know there are two methods “fieldEntered” and “fieldExited”.

In FieldEntered, we have to execute PLSQL procedure and get the results and display it to user.

In FieldExited, we have to get the values selected by the user in the LOV.

public void fieldEntered(MWAEvent mwaevent)
        throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException {

ses = mwaevent.getSession();

String s = UtilFns.fieldEnterSource(ses);

if (s.equals("TEST.LOV")) {

userLOVEntered(mwaevent);

return;

}

}

public void fieldExited(MWAEvent mwaevent) throws AbortHandlerException,InterruptedHandlerException, DefaultOnlyHandlerException {

ses = mwaevent.getSession();

String s = UtilFns.fieldEnterSource(ses);

if (s.equals("TEST.LOV")) {

userLOVExited(mwaevent);

return;

}

}

In the above code, we call the custom methods userLOVEntered() and userLOVExited() to handle the events.

public void userLOVEntered(MWAEvent mwaevent) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException

{

UtilFns.trace("User LOV Entered");

try{

Session session = mwaevent.getSession();

//set the package and procedure name to be called

pg.getUserLOV().setlovStatement("XXX_MWA_LOV_TEST.XXX_USERS_LOV");

//Parameter Type, parameters and Prompts of the field in LOV

// C – cursor, AS/S – String, N – Numeric, AN - AlphaNumeric

String paramType[] = {"C", "AS" };

String parameters[] = {" ", "S%" };

//Set the prompts and visible fields for LOV result table

//We don’t want user id to be displayed in result table. So we //are setting it to false.

//These fields directly map to the selected columns in SELECT //statement of REF CURSOR

String prompts[] = { "USER_ID", "User Name", "Description" };

boolean flag[] = { false,true,true };

//Associate the properties to the LOV bean

//Properties for SQL Query

pg.getUserLOV().setInputParameterTypes(paramType);

pg.getUserLOV().setInputParameters(parameters);

//Properties for LOV Result Table

pg.getUserLOV().setSubfieldPrompts(prompts);

pg.getUserLOV().setSubfieldDisplays(flag);

}

catch(Exception e){

UtilFns.error("Error in calling LOV");

}

}

In the above code, we have pointed out the PLSQL procedure to be executed for List of Values and also we set the parameters, parameter types. Also, we mentioned the prompts for LOV results table and also what are all the visible fields available to user.

In this example, we have hardcoded the input parameter to “S%” so that the result set will have all users from FND_USER starting with “S”. In real time scenario, we can link this parameter dynamically to any variables.

public void userLOVExited(MWAEvent mwaevent) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException

{

UtilFns.trace("User LOV Exited");

try{

//Get the selected row in a vector and print it

Vector v = pg.getUserLOV().getSelectedValues();

if(v!=null) {

UtilFns.trace("first " + v.elementAt(0).toString());

UtilFns.trace("second " + v.elementAt(1).toString());

UtilFns.trace("third " + v.elementAt(2).toString());

}

}

catch(Exception e){

UtilFns.error("Error in processing LOV");

}

}

In the above method, as soon as the user selects the values, we get the selected values in a Vector.

After that we print the user_id, user name and description of the selected user in the Log.

See the following screen shots for further understanding.

Fig 1: Mobile page with Text Bean and LOV

Fig 2: When the user clicks LOV, result page is displayed in a different window.

Fig 3: After the value is selected, the LOV field is populated with the selected value.

Values printed in Log file:

[Fri Feb 15 14:50:11 CET 2008] (Thread-15) User LOV Entered

[Fri Feb 15 14:51:39 CET 2008] (Thread-15) CustomFListener:fieldExited:fldName = TEST.LOV

[Fri Feb 15 14:51:39 CET 2008] (Thread-15) User LOV Exited

[Fri Feb 15 14:51:39 CET 2008] (Thread-15) first 1589

[Fri Feb 15 14:51:39 CET 2008] (Thread-15) second SENTHILK

[Fri Feb 15 14:51:39 CET 2008] (Thread-15) third Shanmugam, SenthilKumar

The above error log is done by the code written in userLOVExited() method.

In this example, we have just printed the selected value in the Log file. In real time scenario, we can use this selected value to be the criteria for the next field or it will be used to do some validations etc.

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