Trouble in obtaining a list that comes from a web service

[abuitr...@gmail.com]

I'm having trouble in creating a list that is obtained from a web service. The following error appears the first time we press the action button but once we press ok to the error and re-press the action button it will create the list properly.

The following error: 

java.lang.NullPointerException
        at java.util.ArrayList.<init>(Unknown Source)
        at com.codename1.ui.list.DefaultListModel.<init> (DefaultListModel.java:60)
        at userclasses.StateMachine.initListModelList(StateMachine.java:199)
        at generated.StateMachineBase.setListModel(StateMachineBase.java:1316)
        at com.codename1.ui.util.UIBuilder.createComponent(UIBuilder.java:1422)
        at com.codename1.ui.util.UIBuilder.createComponent(UIBuilder.java:1363)
        at com.codename1.ui.util.UIBuilder.createContainer(UIBuilder.java:409)
        at com.codename1.ui.util.UIBuilder.createContainer(UIBuilder.java:394)
        at com.codename1.ui.util.UIBuilder.showContainerImpl(UIBuilder.java:2279)
        at com.codename1.ui.util.UIBuilder.showContainer(UIBuilder.java:2161)
        at com.codename1.ui.util.UIBuilder$FormListener.actionPerformed(UIBuilder.java:2772)
        at com.codename1.ui.util.EventDispatcher.fireActionSync(EventDispatcher.java:383)
        at com.codename1.ui.util.EventDispatcher.fireActionEvent(EventDispatcher.java:326)
        at com.codename1.ui.Form.actionCommandImplNoRecurseComponent(Form.java:1228)
        at com.codename1.ui.Button.fireActionEvent(Button.java:372)
        at com.codename1.ui.Button.released(Button.java:407)
        at com.codename1.ui.Button.pointerReleased(Button.java:495)
        at com.codename1.ui.Form.pointerReleased(Form.java:2194)
        at com.codename1.ui.Form.pointerReleased(Form.java:2140)
        at com.codename1.ui.Component.pointerReleased(Component.java:2319)
        at com.codename1.ui.Display.handleEvent(Display.java:1766)
        at com.codename1.ui.Display.edtLoopImpl(Display.java:970)
        at com.codename1.ui.Display.mainEDTLoop(Display.java:899)
        at com.codename1.ui.RunnableWrapper.run(RunnableWrapper.java:119)
        at com.codename1.impl.CodenameOneThread.run(CodenameOneThread.java:176)
java.lang.NullPointerException
        at com.codename1.ui.Container.insertComponentAt(Container.java:423)
        at com.codename1.ui.Container.addComponent(Container.java:403)
        at com.codename1.ui.Form.addComponent(Form.java:836)
        at com.codename1.ui.util.UIBuilder.showContainerImpl(UIBuilder.java:2285)
        at com.codename1.ui.util.UIBuilder.showContainer(UIBuilder.java:2161)
        at com.codename1.ui.util.UIBuilder$FormListener.actionPerformed(UIBuilder.java:2772)
        at com.codename1.ui.util.EventDispatcher.fireActionSync(EventDispatcher.java:383)
        at com.codename1.ui.util.EventDispatcher.fireActionEvent(EventDispatcher.java:326)
        at com.codename1.ui.Form.actionCommandImplNoRecurseComponent(Form.java:1228)
        at com.codename1.ui.Button.fireActionEvent(Button.java:372)
        at com.codename1.ui.Button.released(Button.java:407)
        at com.codename1.ui.Button.pointerReleased(Button.java:495)
        at com.codename1.ui.Form.pointerReleased(Form.java:2194)
        at com.codename1.ui.Form.pointerReleased(Form.java:2140)
        at com.codename1.ui.Component.pointerReleased(Component.java:2319)
        at com.codename1.ui.Display.handleEvent(Display.java:1766)
        at com.codename1.ui.Display.edtLoopImpl(Display.java:970)
        at com.codename1.ui.Display.mainEDTLoop(Display.java:899)
        at com.codename1.ui.RunnableWrapper.run(RunnableWrapper.java:119)
        at com.codename1.impl.CodenameOneThread.run(CodenameOneThread.java:176) 



The code is as follow:

private String USERID = "";
	private String USERPA = "";
	private String URL = "http://134.177.251.210:9080/DIBS_SERVER_MOVIL_DEMO/servlet/com.datapro.dibs.servlets.JSServicesList";
	// private String URL =
	// "http://localhost:9081/DIBS_SERVER_MOVIL_DEMO/servlet/com.datapro.dibs.servlets.JSServicesList";

	private Vector lsaccounts = null;
	private Vector lsretailaccounts = null;
        private Vector lsbenes = null;  

@Override
    protected void onMenu_CuentasButtonAction(Component c, ActionEvent event) {
        
        ConnectionRequest r = new ConnectionRequest() {         
                        String h = "";

                        @Override
                        protected void readResponse(InputStream input) throws IOException {
                                XMLParser xmlp = new XMLParser();
                                h = "" + xmlp.parse(new InputStreamReader(input));
                                System.out.println(h);
                        }
                        
                        @Override
                        protected void postResponse() {
                                String error = "X";
                                Result result = Result.fromContent(h, Result.XML);
                                error = result.getAsString("//consultarSaldos/errorcode");
                                
                                if (!error.trim().equals("'0'")) {
                                        Dialog.show("Error", "Informacion Invalida", "OK", null);
                                } else {
                                        String accountAvailable[] = result.getAsStringArray("//accountavailable");
                                        String accountCurrency[] = result.getAsStringArray("//accountcurrency");
                                        String accountNumber[] = result.getAsStringArray("//accountnumber");
                                        String accountType[] = result.getAsStringArray("//accounttype");
                                        
                                        lsaccounts = new Vector();
                                        int numel = accountAvailable.length;
                                        for (int i = 0; i < numel; i++) {
                                                
                                                String accountAvailable1 = accountAvailable[i];
                                                String accountCurrency1 = accountCurrency[i];
                                                String accountNumber1 = accountNumber[i];
                                                String accountType1 = accountType[i];
                                                
                                                accountAvailable1 = accountAvailable1.trim().substring(1, accountAvailable1.trim().length() - 1);
                                                accountCurrency1 = accountCurrency1.trim().substring(1, accountCurrency1.trim().length() - 1);
                                                accountNumber1 = accountNumber1.trim().substring(1, accountNumber1.trim().length() - 1);
                                                accountType1 = accountType1.trim().substring(1, accountType1.trim().length() - 1);
                                                
                                                dbAccount accbean = new dbAccount();
                                                String accnumt = "";
                                                if (accountNumber1.length() > 4) {
                                                        accnumt = accountNumber1.substring( accountNumber1.length() - 4, accountNumber1.length());
                                                } else {
                                                        accnumt = accountNumber1;
                                                }
                                                
                                                String accnumMask = accountType1 + " No. **** " + accnumt + " " + accountCurrency1 + " "+ accountAvailable1;
                                                accbean.setaccNum(accnumMask);
                                                accbean.setaccAvai(accountCurrency1 + " "+ accountAvailable1);
                                                accbean.setaccTyp(accountType1);
                                                lsaccounts.add(accnumMask);
                                        }
                                }
                        }
        };
        
        r.setUrl(URL);
                r.setPost(false);
                r.addArgument("PB", "2");
                r.addArgument("USERID", USERID);
                r.addArgument("USERPA", USERPA);
                InfiniteProgress prog = new InfiniteProgress();
                Dialog dlg = prog.showInifiniteBlocking();
                r.setDisposeOnCompletion(dlg);
                NetworkManager.getInstance().addToQueue(r);
                r.getResponseData();

    }
    
    @Override
    protected boolean initListModelList(List cmp) {
        
        cmp.setModel(new com.codename1.ui.list.DefaultListModel(lsaccounts));
        return true;
    }



P.S. I used the rendering list method in the theme.

The expected output is to have different accounts listed as one first presses the button. 

Thanks.

[Shai Almog]

lsaccounts is null initially so you obviously get a null pointer exception. After you fetch it, then it is no longer null and it starts working.

protected boolean initListModelList(List cmp) {
    if(lsaccounts == null) {
          cmp.setModel(new com.codename1.ui.list.DefaultListModel());
    } else {
          cmp.setModel(new com.codename1.ui.list.DefaultListModel(lsaccounts));
    }        
    return true;    
}

[abuitr...@gmail.com]

Thank you for your help, but with this code it will generate first a blank list and then actual list will load. How does one prevent the blank list?

</code

...

[Shai Almog]

addToQueue() returns immediately so the getData() following it is meaningless.
You can change it to addToQueueAndWait() which might be what you are after.