[PyQt] Completely removing items from a layout

[Baz Walter]

Lee Harr wrote:
> I wrote about this a couple of weeks ago, but I did not have a small
> working example to show the problem I'm having. Now I do.
> 
> 
> I have a layout created in Qt4 Designer which I fill with a series of
> complex layouts at runtime. That works great. Later on, I want
> to completely remove all of them and fill it up again with a
> different set.
> 
> The re-filling up part works fine, but the original set of items is
> still visible and I can't work out how to get rid of them completely.
> 
> 
> The code looks something like the following. Resize the window and
> you will see a blob that is the leftovers from the first call to fillup()
> 
> 
> 
> import sys
> from PyQt4 import QtGui
> 
> class Ui_MainWindow(object):
>     def setupUi(self, MainWindow):
>         self.centralwidget = QtGui.QWidget(MainWindow)
>         self.verticalLayout = QtGui.QVBoxLayout(self.centralwidget)
>         MainWindow.setCentralWidget(self.centralwidget)
> 
> 
> class L2(QtGui.QHBoxLayout):
>     # Represents a more complex layout to be placed inside verticalLayout
>     def __init__(self, name):
>         QtGui.QHBoxLayout.__init__(self)
>         nm = QtGui.QLabel(name)
>         self.addWidget(nm)
> 
> 
> class MainWindow(QtGui.QMainWindow):
>     def __init__(self):
>         QtGui.QMainWindow.__init__(self)
>         self.ui = Ui_MainWindow()
>         self.ui.setupUi(self)
>         self.fillup()
>         self.unfill()
>         self.fillup()
> 
>     def fillup(self):
>         for name in [str(n) for n in range(10)]:
>             txt = name*20
>             self.ui.verticalLayout.addLayout(L2(txt))
> 
>     def unfill(self):
>         # This is the troublesome one.
>         # How do I get rid of the contents of the layout completely?
> 
>         vl = self.ui.verticalLayout
>         while vl.count():
>             item = vl.itemAt(0)
>             vl.removeItem(item)

you need to delete both the layouts and their contents:

     def unfill(self):
         def deleteItems(layout):
             if layout is not None:
                 while layout.count():
                     item = layout.takeAt(0)
                     widget = item.widget()
                     if widget is not None:
                         widget.deleteLater()
                     else:
                         deleteItems(item.layout())
         deleteItems(self.ui.verticalLayout)

> 
> if __name__ == '__main__':
>     app = QtGui.QApplication(sys.argv)
>     win = MainWindow()
>     win.show()
>     app.exec_()