Listbox and Groupsmodel

asked 2011-08-10 12:50:11 +0800

twiegand
1807 ● 3

updated 2011-08-10 12:54:13 +0800

Hi everyone,

We are trying to implement a <listbox> using the groupsmodel and seem to be running into significant hurdles with databinding and getting it to render content properly (running ZK 5.0.7.1).

Please consider the following Java snippet:

class Datem {
	String string1;
	String string2;
	
	public Datem(String val1, String val2){
		string1 = val1;
		string2 = val2;
	}				
	
	public String getString1(){
		return string1;
	}
	
	public void setString1(String val){
		string1 = val;
	}
	
	public String getString2(){
		return string2;
	}
	
	public void setString2(String val){
		string2 = val;
	}
	
	public String toString(){
		return string1 + " : " + string2;
	}
}

Object[][] data = {
	{new Datem("Cell 1-0", "First")}, 									//Group 1
	{new Datem("Cell 2-0", "Second"), new Datem("Cell 2-1", "Third")}, 					//Group 2
	{new Datem("Cell 3-0", "Fourth"), new Datem("Cell 3-1", "Fifth"), new Datem("Cell 3-2", "Sixth")} 	//Group 3
};

Object[] heads = {"Group 1", "Group 2", "Group 3"};

GroupsModel groupsmodel = new SimpleGroupsModel(data, heads);

All of the examples I can find for using a <listbox> with a groupsmodel have very minimal decoration on the <listbox> component itself.  Here is some example zul:

<listbox  model="@{groupsmodel}" selectedItem="@{selected}"/>
<separator/>
<hlayout>
	<textbox value="@{selected.string1}"/>
	<separator/>
	<textbox value="@{selected.string2}"/>
</hlayout>

This seems to render but databinding does not seem to work as a normal <listbox> would.  For example, if you select a row and then update the value in one of the textboxes below, the value does not get refreshed in the listbox above.  However, it does seem to be saving the backing information because if you select a different row and then come back to the original one, the changed value does indeed show up in the textbox ( just not in the listbox).
 

Because of the need to put values in columns, assign custom attributes, capture events, etc. we need to do more than what the above zul provides.  However, if we try to add "body" to the listbox, the Null Pointer Errors (NPE) come fast and furious.  For example, here is the same zul with more detail:

<listbox  model="@{groupsmodel}" selectedItem="@{selected}">
	<listhead>
		<listheader label="Name"/>
		<listheader label="Place"/>
	</listhead>

	<listgroup />  <!-- Should this be used here?  If so, what should it be pointed to? -->

	<listitem self="@{each=item}" value="@{item}">
		<listcell label="@{item.string1}"  />
		<listcell label="@{item.string2}"  />
	</listitem>
</listbox>
<separator/>
<hlayout>
	<textbox value="@{selected.string1}"/>
	<separator/>
	<textbox value="@{selected.string2}"/>
</hlayout>

As you'll notice in the zul code above, there is a <listgroup> component.  The inclusion/exclusion of this component does not seem to affect the results.  Maybe there is something that the <listgroup> needs to be pointed to like <listitem>?

Also of note is that once you click through the NPE dialogue boxes and then click on a row, the values populate correctly.  Unfortunately, if you try to open/close a group, the NPE errors start firing again.

We would like to stay away from using a listitemrender if at all possible.  Getting databinding to work with that seems rather messy and I've got team members with varying levels of skill.

Can anyone point me in the right direction please?  Perhaps there is some documentation I have missed in my searches.

I sure appreciate any help.  My apologies for the lengthy post.

Kind regards,

Todd