[Qt-qml] Calling slots with binding

[Cristian Daniel Stamateanu]

Thanks Aaron, it works with property alias.

aaron.kennedy at nokia.com wrote:
> Hi,
> 
> Bindings are intentionally unidirectional.  As a binding can be a complex expression there is no way for us to automatically reverse it.
> 
> In the specific case you describe you could us a property alias.  
> 
> Rectangle {
>     property alias title: myChild.title
>     Child {
>         id: myChild
>     }
> }
> 
> Aliases are not bindings.  Instead reading and writing to the title property of the rectangle is internally translated into reading and writing the title property of the Child.
> 
> Cheers,
> 
> Aaron 
> 
> On 30/06/2010, at 11:01 PM, "ext Cristian Daniel Stamateanu" <cristi.qt at gmail.com> wrote:
> 
>> Ok, here is what I found, it seems that using bindings in QML, values 
>> are transfered to child components but when changed inside child the 
>> value is not sent back to the parent:
>>
>> //Parent.qml
>> Rectangle{
>> 	property string title: "initial value"
>> 	id: root
>>
>> 	Child{
>> 		title: root.title
>> 	}
>> }
>>
>> //Child.qml
>> Rectangle{
>> 	property string title
>> 	id:child
>> 	...
>> 	//JS script
>> 	{
>> 		child.title = "Child modified value";
>> 		// I expected this to reflect back in parent or 	
>> 		// whatever component was bound to it
>> 	}
>> 	...
>> 	
>> }
>>
>> Is this normal? Is there a workaround
>>
>> Regards,
>> Cristi
>>
>> Cristian Daniel Stamateanu wrote:
>>> Thanks Kent, You were right on both counts. I don't need a QScriptValue 
>>> and the value is not sent from qml for some reason. I will investigate 
>>> further.
>>>
>>> BR.
>>> Cristian Stamateanu
>>>
>>> On Tue, 29 Jun 2010 18:39:36 +0300, Kent Hansen <kent.hansen at nokia.com> 
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> On 29. juni 2010 16:58, ext Cristian Daniel Stamateanu wrote:
>>>>> Hello,
>>>>>
>>>>> I have the following problem : I have a class declaring the following 
>>>>> slot:
>>>>>
>>>>> void RssFeedManager::addFeedEx(const QScriptValue&  name,const
>>>>> QScriptValue&  address )
>>>>> {
>>>>>          bool nameIsString = name.isVariant();
>>>>>          QString str = name.toString();
>>>>>         ...
>>>>> }
>>>>>
>>>>> and I am calling this slot from QML
>>>>>
>>>>> This works ok:
>>>>> feedManager.addFeedEx( "whatever", addFeedView.address );
>>>>>
>>>>> while using a binding to a property declared in addFeedView like
>>>>> property string name;
>>>>>
>>>>> feedManager.addFeedEx( addFeedView.name, addFeedView.address );
>>>>>
>>>>> is not working.
>>>>> In the c++ side I am getting a string only it is an empty one.
>>>>>
>>>>> Any thoughts?
>>>>>
>>>> Have you checked that the name is indeed non-empty on the JS side?
>>>> Does it work if you declare the slot as taking a QString argument (why
>>>> do want to receive it as a QScriptValue)?
>>>> What type is the script value, is it an object? If so, does
>>>> QScriptValue::toVariant() return anything? QML has a special "hook" to
>>>> allow converting a script value to a variant, but no hook for the
>>>> toString case AFAICT.
>>>>
>>>> Regards,
>>>> Kent
>>>> _______________________________________________
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>>>> Qt-qml at trolltech.com
>>>> http://lists.trolltech.com/mailman/listinfo/qt-qml
>>>
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