ZK NullPointerException in a ListModel with empty data and Sourced file: inline evaluation of: ``

Question

hi guys i am very new to ZK i am receiving 2 errors please guide me throught sorry if this errors and very easy for a not newbie. here is the code.

public void createItem(Listbox list) 
{          
    BindingListModelList model=(BindingListModelList)list.getModel();       
    System.out.println((list==null));//prints false
    System.out.println((model==null));//prints true             
    if(model==null){ list.setModel(new ListModelList());System.out.println("After Set New Model: "+(list.getModel()==null));//prints true}      
    model=(BindingListModelList)list.getModel();
    System.out.println((model==null));//prints true
    model.add(getMeridaManager().createNewMeridaItem(list));//throws NPE
}   

public void loadGrid(Listbox list)
{
    //here i load the model but when is a empty ALL arrayList throws exception on createItem(Listbox list) 

    java.util.List<DianaMerida>all = meridaManager.getAllMeridas();
    BindingListModelList rl=new BindingListModelList(all,false);        
    list.setModel(rl);
}

here if the .zul when i uses the past code. i was wonder if is a empty collection how can i add new items to the model by example a add new record later.

2 question i have the following code in a zul.

checkbox id="isclosecheckbox" checked="@{d.c03}"     onCheck="myClass.checkBoxListener2(datebox1);"
datebox id="datebox1" cols="10" format="short" mold="rounded"

but when the checkBox is clicked and the myClass.checkBoxListener2(datebox1); method is called i get the following error.

03/02/2013 04:30:41 PM org.zkoss.zk.ui.impl.UiEngineImpl handleError:1280 GRAVE: >>org.zkoss.zk.ui.UiException: Sourced file: inline evaluation of: . . . '' : Undefined argument: datebox1 : at Line: 300 : in file: inline evaluation of:
. . . '' : ( datebox1 )

Sourced file: inline evaluation of: . . . '' : Undefined argument: datebox1 : at Line: 300 : in file: inline evaluation of:
. . . '' : ( datebox1 )

Answer 1

If you are using MVVM architecture you can add a new item in listbox like this..

    <?page title="new page title" contentType="text/html;charset=UTF-8"?>
<zk>
    <window title="new page title" border="normal"
        viewModel="@id('vm') @init('com.team.MyListbox')" apply="org.zkoss.bind.BindComposer">
        <button label="AddItem" onClick="@command('addNewItem')"></button>
        <listbox model="@bind(vm.dataList)">
            <listhead>
                <listheader value="A"></listheader>
                <listheader value="B"></listheader>
                <listheader value="C"></listheader>

            </listhead>
            <template name="model" var="mymodel">
                <listitem>
                    <listcell>

                        <textbox value="@bind(mymodel.a)" />
                    </listcell>
                    <listcell>
                        <label value="@bind(mymodel.b)" />

                    </listcell>
                    <listcell>
                        <label value="@bind(mymodel.c)" />

                    </listcell>
                </listitem>
            </template>
        </listbox>
    </window>
</zk>

And Java Code or ViewModel is...

package com.team;

import java.util.ArrayList;
import java.util.List;

import org.zkoss.bind.annotation.AfterCompose;
import org.zkoss.bind.annotation.Command;
import org.zkoss.bind.annotation.ContextParam;
import org.zkoss.bind.annotation.ContextType;
import org.zkoss.bind.annotation.NotifyChange;
import org.zkoss.zk.ui.Component;

public class MyListbox {

    private List<Data> dataList;

    @AfterCompose
    public void afterCompose(@ContextParam(ContextType.VIEW) Component view) {
        try {
            dataList = new ArrayList<Data>();
            Data data;
            data = new Data("a1", "b1", "c1");
            dataList.add(data);
            data = new Data("a2", "b2", "c2");
            dataList.add(data);
            data = new Data("a3", "b3", "c3");
            dataList.add(data);
        } catch (Exception e) {

        }
    }

    @Command
    @NotifyChange("dataList")
    public void addNewItem(){
        Data data = new Data("", "", "");
        dataList.add(data);
    }
    public List<Data> getDataList() {
        return dataList;
    }

    public void setDataList(List<Data> dataList) {
        this.dataList = dataList;
    }

    public class Data {
        String a;
        String b;
        String c;
        public String getA() {
            return a;
        }
        public String getB() {
            return b;
        }
        public String getC() {
            return c;
        }
        public void setA(String a) {
            this.a = a;
        }
        public void setB(String b) {
            this.b = b;
        }
        public void setC(String c) {
            this.c = c;
        }
        public Data(String a, String b, String c) {
            super();
            this.a = a;
            this.b = b;
            this.c = c;
        }

    }
}

And for your checkbox issue you can use code in zul something like this..

<checkbox checked="@bind(vm.checkboxValue)" onCheck="@command('checkboxClicked'  />

Here i bind checkbox value with this variable

checkboxValue

and anyone click on the checkbox i am calling a method

checkboxClicked

where i can perform my business logic