[PySide] What can be returned from a slot?

[Aaron Richiger]

Hello Yosef!

I think, this question is related to an earlier one from me... Anatoly 
then told me the truth about lifetimes of QObjects that are created in 
methods without any parent reference. They won't survive such a method 
call as you try to do. By giving your model a parent reference that 
survives the method call, the model will be available as well after the 
return statement. The following code also shows, that the "QVariant" 
trick is not necessary, but setting the result type to QObject is 
enough. I hope this helps...
Aaron


################ Python code ##################

import sys
from PySide import QtCore, QtGui, QtDeclarative

class TargetListModel(QtCore.QAbstractListModel):

     def __init__(self, targets, parent):
         super(TargetListModel, self).__init__(parent)
         self._targets = targets
         self.setRoleNames({0: 'posx', 1: 'posy'})

     @QtCore.Slot(result=int)
     def rowCount(self, parent=QtCore.QModelIndex()):
         return len(self._targets)

class Console(QtCore.QObject):

     @QtCore.Slot(result=QtCore.QObject)
     def get_model(self):
         return TargetListModel("asdf", self)

if __name__ == '__main__':
     app = QtGui.QApplication(sys.argv)
     view = QtDeclarative.QDeclarativeView()
     con = Console()
     context = view.rootContext()
     context.setContextProperty("con", con)
     view.setSource(QtCore.QUrl('view.qml'))
     view.show()
     sys.exit(app.exec_())


############### QML code in view.qml #########################

import Qt 4.7

Rectangle {
     id: page

     width: 500; height: 200
     color: "lightgray"

     Text {
         id: helloText
         text: "Hello world!"
         anchors.horizontalCenter: page.horizontalCenter
         y: 30
         font.pointSize: 24; font.bold: true
     }

     Rectangle {
         id: button
         width: 150; height: 40
         color: "darkgray"
         anchors.horizontalCenter: page.horizontalCenter
         y: 120
         MouseArea {
             id: buttonMouseArea
             objectName: "buttonMouseArea"
             anchors.fill: parent
             onClicked: {
                 helloText.rotation = con.get_model().rowCount()
             }
         }
         Text {
             id: buttonText
             text: "Press me!"
             anchors.horizontalCenter: button.horizontalCenter
             anchors.verticalCenter: button.verticalCenter
             font.pointSize: 16;
         }
     }
}