Remove all items from a layout

Question

I was trying to find something that would take a qt layout and delete everything from it. Just to imagine what the window looks like - I have:

QVBoxLayout
     | ------QHboxLayout
                 |---------QWidget
     | ------QHboxLayout
                 |---------QWidget
            .........

So I need something that I can call recursively to CLEAR AND DELETE all the stuff from my parent QVBoxLayout. I tried things mentioned here (Clear all widgets in a layout in pyqt) but none of them work (no correct answer marked anyway). My code looks like this:

def clearLayout(self, layout):
    for i in range(layout.count()):
        if (type(layout.itemAt(i)) == QtGui.QHBoxLayout):
            print "layout " + str(layout.itemAt(i))
            self.clearLayout(layout.itemAt(i))
        else:
            print "widget" + str(layout.itemAt(i))
            layout.itemAt(i).widget().close()

But it gives an error:

               layout.itemAt(i).widget().close()
            AttributeError: 'NoneType' object has no attribute 'close'

=>EDIT This kinda works (but doesn't if there is any other Layout than HBoxLayout:

def clearLayout(self, layout):
    layouts = []
    for i in range(layout.count()):
        if (type(layout.itemAt(i)) == QtGui.QHBoxLayout):
            print "layout " + str(layout.itemAt(i))
            self.clearLayout(layout.itemAt(i))
            layouts.append(layout.itemAt(i))
        else:
            print "widget" + str(layout.itemAt(i))
            if (type(layout.itemAt(i)) == QtGui.QWidgetItem):
                layout.itemAt(i).widget().close()

ekhumoro · Accepted Answer · 2017-01-27T18:40:33.203

30

The safest way to clear a layout is to extract the items with its takeAt method, and then explicitly delete any widgets with deleteLater:

def clearLayout(self, layout):
    if layout is not None:
        while layout.count():
            item = layout.takeAt(0)
            widget = item.widget()
            if widget is not None:
                widget.deleteLater()
            else:
                self.clearLayout(item.layout())

edited Jan 27 '17 at 18:40

answered Feb 21 '12 at 19:22

ekhumoro

115,249
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This is a more elegant solution. Thank you – tisaconundrum Dec 27 '16 at 22:16
it isn't clear what `self` is in this context – pretzlstyle Apr 16 '23 at 19:49
@pretzlstyle It doesn't really matter what `self` is. The OP's code uses a method of a class, so that's what my answer uses. It could just as easily be function with no `self` at all. – ekhumoro Apr 16 '23 at 21:27
thanks for the solution, is all I expected to be a built-in method in pyside6 – sebwr May 23 '23 at 13:37

Avaris · Answer 2 · 2012-02-21T10:31:20.540

7

The problem with your code is QLayout.itemAt() returns a QLayoutItem, QWidgetItem or QSpacerItem depending on the item at that position. So the condition:

type(layout.itemAt(i)) == QtGui.QHBoxLayout

will never be True and you will be trying to do .widget() for a QLayoutItem and that returns None. Thus the error you get. Another thing is, you need to loop backwards. Because removing things from the beginning will shift items and change the order of items.

You need to write your function like this:

def clearLayout(self, layout):
    for i in reversed(range(layout.count())):
        item = layout.itemAt(i)

        if isinstance(item, QtGui.QWidgetItem):
            print "widget" + str(item)
            item.widget().close()
            # or
            # item.widget().setParent(None)
        elif isinstance(item, QtGui.QSpacerItem):
            print "spacer " + str(item)
            # no need to do extra stuff
        else:
            print "layout " + str(item)
            self.clearLayout(item.layout())

        # remove the item from layout
        layout.removeItem(item)

edited Feb 21 '12 at 10:31

answered Feb 21 '12 at 09:45

Avaris

35,883
7
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almost there but not quite :) Thanks anyway :) When I run the function you supplied all my QHboxLayouts get clasified as spacers. Since this is not true " returns a QLayoutItem, QWidgetItem or QSpacerItem depending on the item at that position." => My itemAt returns QHboxLayout which is not QLayoutItem – kosta5 Feb 21 '12 at 10:16
I sorta fixed it like this: def clearLayout(self, layout): for i in range(layout.count()): if (type(layout.itemAt(i)) == QtGui.QHBoxLayout): print "layout " + str(layout.itemAt(i)) self.clearLayout(layout.itemAt(i)) else: print "widget" + str(layout.itemAt(i)) if (type(layout.itemAt(i)) == QtGui.QWidgetItem): layout.itemAt(i).widget().close() – kosta5 Feb 21 '12 at 10:17
@user965847: That's weird. I get `QLayoutItem`s for my trials. Anyways, I edited the code. Try this one. – Avaris Feb 21 '12 at 10:32

Remove all items from a layout

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