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");
}
}
I have checked the VisualItemModel / ObjectModel. They could hold
object but they are not based on QAbstractItemModel . They can not be
used as a dynamic data provider to another component like ListView.
So I am very confused with the design of
ListMode/VisualItemModel/VisualDataItemModel.
1) Why ListModel discard the method of its contained data?
2) What is the purpose of VisualItemModel/VisualDataItem? Why they are
not based on QAbstractItemModel?
3) Any alternative solution to store the object list?
Thank for you advise.
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