Re: [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 -->