I'm not talking about Designer plugins or about creating new widget classes with PyQt, that can be used in a dialog editor. I'm talking about querying the properties of the existing Qt widget classes.On Do, 2004-02-19 at 11:55, Ulrich Berning wrote:Phil Thompson schrieb:On Wednesday 18 February 2004 19:04, Eron Lloyd wrote:Nevertheless it makes sense to implement QMetaObject and QMetaProperty, just in case someone plans to build a kind of dialog editor with PyQt (in the future, we want to give our customers the facility to create or modify dialogs or dialog components inside the application).I have done a lib to insert PyQt Widget as Plugin in QtDesinger with editable properties (if you interested in this search for qtdesinger or qwidgetplugin in the mail archive or just ask me). Jim, David and Phil helped me to see that there is no point in implementing QMetaObject in PyQt but do a Proxy in C++. The main reason were: There is little use for those MetaObjects functions from Python space. Even if you write a dialog editor in PyQt you would use the Qt functions and they would query the MetaObjects. So even in this case those queries would come from C++ space. >From C++ space it looks like every class is a object of one of the wrapper class even if it only indirectly subclass of a wrapper class. So from C++ space it seams that e.g. a python object of a QWidget class has the same class as a object of a python class derived from QWidget. Since most of the MetaObject stuff is done with statics this would complicate it further. Like I said, just ask or look at the archives for more information.regards Roland
If I would build a dialog editor, creating widgets would be done in the following way:
1.) The user selects a Qt widget class from a toolbox.
2.) The dialog editior creates an instance of that widget class and places it into the dialog window.
3.) The dialog editor sets up a property editor to modify the properties of that widget instance.
In C++, I can use QObject::metaObject() to get the QMetaObject of the widget.
Then I can do QMetaObject::numProperties() to get the number of properties and in a loop QMetaObject::property() to get all QMetaProperty instances.
The QMetaProperty instances have all the necessary informations, needed to set up a property editor.
This will work for most of the Qt widget classes, only a few widget classes may need special handling.
In PyQt, I can't do this, because the above classes and methods are not implemented. The only way to manage this in PyQt, is to write a huge amount of code for every widget class, to set up a property editor for that widget class. Another disadvantage of doing it this way is that with every new Qt release, the property definitions of a widget class may have changed, so the code does not work any longer.
Ulli
