[Development] [QML] ListModel discards item's method

[Nurmi J-P]

On 03 May 2014, at 16:04, Ben Lau <xbenlau at gmail.com> wrote:

> Hi,
> 
> I have few questions about the implementation of ListModel and the design principle about using models with object in QML application. 
> 
> I would like to use a model class to hold a list of item (or  C++ QObject ) with custom methods / slot functions. However, I found that after the item/QObject is appended to the ListModel, then access the model to get back the object. The associated method will become a property value and not able to call.
> 
> The following code demonstrates the problem:
> 
> import QtQuick 2.0
> import QtTest 1.0
> 
> TestCase {
> 
>     Item {
>         id : testItem
>         property string name : "testObject"
>         function testMethod() {
>             return -1;
>         }
>     }
> 
>     ListModel {
>         id : listModel
>     }
> 
>     function test_ListModel() {
>         listModel.append(testItem);
>         compare(listModel.count , 1);
> 
>         var item = listModel.get(0);
> 
>         compare(item !== testItem, true); // They are not the same object
>         compare(item.name , "testObject");
> 
>         expectFail("","The testMehod() should be a function but now it becomes a property");
>         compare(typeof item.testMethod , "function");
>     }
> 
> }

Hi,

Notice that ListModel::append() takes a JS dictionary, and get() returns it. Make it something like:

   listModel.append({"item": testItem});
   var obj = listModel.get(0);
   compare(obj.item, testItem);

--
J-P Nurmi