[Laszlo-user] lz.list and lazy replication: onselect not firing when the list scrolls

[P T Withington]

It's possible this was recently fixed:

http://jira.openlaszlo.org/jira/browse/LPP-2339

On 2008-10-24, at 16:07EDT, Paulo Scardine wrote:

> Hi guys,
>
> I use lz.list frequently. When using a large dataset, I always use  
> textlistitem with lazy replication. The problem is that if the list  
> has an item selected, and you scroll down the list, the selected  
> textlistitem will be reused. This causes some unpleasant/ 
> inconsistent behavior: another random entry in the list will get  
> selected (the one which reuse the same textlistitem from the  
> previous selection); list.getSelection() will reflect the new value.  
> Automatically selecting another random entry just scrolling down is  
> unexpected; also, in this case onselect event will not fire.
>
> I think the behavior I get when using the following hack is more  
> consistent with similar widgets from other toolkits:
>
>       <class name="xtd_list" extends="list">
>               <attribute name="selectedValue" value="null"/>
>               <handler name="onselect" args="d">
>                       this.selectedValue = d.value;
>               </handler>
>               <method name="getValue">
>                       return this.selectedValue;
>               </method>
>               <method name="clearSelection" args="keepSelectedValue">
>                       super.clearSelection();
>                       if(!keepSelectedValue) {
>                               this.selectedValue = null;
>                       }
>               </method>
>       </class>
>       <class name="xtd_textlistitem" extends="textlistitem">
>               <handler name="ondata" args="d">
>                       if(this.value == parent.selectedValue) {
>                               parent.select(this);
>                       } else if(this.selected) {
>                               parent.clearSelection(true);
>                       }
>               </handler>
>       </class>
>
> This makes only works with single selection and if "value" is unique  
> for each item, which is almost always true for me, but I'm wondering  
> if someone would came up with a more generic or elegant solution.
>
> Thanks in advance,
> --
> Paulo Scardine
>
> <!-- begin testcase -->
>       <dataset name="ds">
>           <records>
>                <record value="1">Value1</record>
>                <record value="2">Value1</record>
>                <record value="3">Value1</record>
>                <record value="4">Value1</record>
>                <record value="5">Value1</record>
>                <record value="6">Value1</record>
>                <record value="7">Value1</record>
>                <record value="8">Value1</record>
>                <record value="9">Value1</record>
>                <record value="10">Value10</record>
>                <record value="11">Value11</record>
>                <record value="12">Value12</record>
>                <record value="13">Value13</record>
>                <record value="14">Value14</record>
>                <record value="15">Value15</record>
>                <record value="16">Value16</record>
>                <record value="17">Value17</record>
>                <record value="18">Value18</record>
>                <record value="19">Value19</record>
>           </records>
>       </dataset>
>       <xtd_list width="200" height="60">
>            <xtd_textlistitem textlistitem text="$path{'text()'}"  
> value="$path{'@value'}">
>                <datapath xpath="local:parent.parent.dscasos:/records/ 
> record" replication="lazy"/>
>            </xtd_textlistitem>
>       </xtd_list>
> <!-- end testcase -->
>