qtreewidget unwanted white space (additional unremovable rows)

Question

I am creating a custom qtreewidget class that autoresizes its window to fit exactly the currently visible elements (I don't want to have to scroll). To do this, I run a count function to find the number of open qtreewidgetitems and their children and set a fixed height from there. However, when I expand a child widget (click the expand arrow on one of my items) the whole view suddenly needs to scroll because there is extra white space at the bottom, despite my count function accurately calculating the needed height. How do I get rid of it?

Below is a working class that can be run directly as is.

import sys
from PyQt4 import QtGui
from PyQt4.QtCore import *
from PyQt4.QtGui import *


class TreeWidget(QTreeWidget):
    def __init__(self, parent=None):
        super(TreeWidget, self).__init__()
        self.installEventFilter(self)
        self.setStyleSheet('''
            background: None;
            border: None;
            outline: None;
            outline-width: 0px;
            selection-background-color: blue;
            ''')
        header = QtGui.QTreeWidgetItem(["Tree", "First"])
        self.setAutoScroll(False)
        self.setHeaderItem(header)
        self.header().close()
        # self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)

    def fill_item(self, item, value):
        item.setExpanded(False)
        if type(value) is dict:
            for key, val in sorted(value.iteritems()):
                child = QTreeWidgetItem()
                child.setText(0, unicode(key))
                # child.doubleClicked.connect(lambda: self.doubleClicked1(child))
                item.addChild(child)
                self.fill_item(child, val)
        elif type(value) is list:
            last = None
            for val in value:
                child = QTreeWidgetItem()
                if type(val) is dict:
                    item.addChild(child)
                    child.setText(0, '[dict]')
                    # child.doubleClicked.connect(lambda: self.doubleClicked1(child))
                    self.fill_item(child, val)
                    last = child
                elif type(val) is list:
                    self.fill_item(last, val)
                else:
                    item.addChild(child)
                    child.setText(0, unicode(val))
                    child.setText(1, 'test')
                    # child.doubleClicked.connect(lambda: self.doubleClicked1(child))
                    child.setExpanded(False)
                    last = child
        else:
            child = QTreeWidgetItem()
            child.setText(0, unicode(val))
            child.setText(1, 'test')
            # child.doubleClicked.connect(lambda: self.doubleClicked1(child))
            item.addChild(child)

    def fill_widget(self, value):
        self.clear()
        self.fill_item(self.invisibleRootItem(), value)

    def resizeEvent(self, event):
        self.resize()

    def resize(self):
        width = 50
        self.header().resizeSection(1, width)
        self.header().resizeSection(0, self.width()-width)
        height = self.visibleCount()
        print height/15
        self.setFixedHeight(height+0)

    def eventFilter(self, source, event):
        if source is self:
            if event.type() == 1:
                self.resize()
            elif event.type() == QEvent.Leave:
                self.clearSelection()
        return QtGui.QTreeWidget.eventFilter(self, source, event)

    def visibleCount(self, parent=0):
        height = 0
        if parent == 0:
            topHeight = 0
            for a in xrange(self.topLevelItemCount()):
                item = self.topLevelItem(a)
                topHeight += self.visualItemRect(item).height()
                if item.isExpanded():
                    height += self.visibleCount(item)
            height += topHeight
        else:
            childHeight = 0
            for a in xrange(parent.childCount()):
                item = parent.child(a)
                childHeight += self.visualItemRect(item).height()
                if item.isExpanded():
                    height += self.visibleCount(item)
            height += childHeight
        return height

    def editClicked(self, parent=0):
        # print 'edit 2'
        if parent == 0:
            for a in xrange(self.topLevelItemCount()):
                item = self.topLevelItem(a)
                print type(item)
                item.setExpanded(True)
                self.editClicked(item)
        else:
            for a in xrange(parent.childCount()):
                item = parent.child(a)
                print type(item)
                item.setText(1, '+')
                item.setExpanded(True)
                self.editClicked(item)

    def doubleClicked1(self, widget):
        print widget


def main():
    app = QtGui.QApplication(sys.argv)
    ex = TreeWidget()
    data = [
        'Make sure ZMQ remote button gets honored',
        'Fill in plot',
        'Remove cycle',
        'Remove current control or make it working',
        'Handle possible startup errors with dialogs',
        'Get improved current read-out (requires hardware changes)',
        ['1','2','3'],
        'Email quench notification'
        ]
    ex.fill_widget(data)
    ex.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

Mel Mel · Accepted Answer · 2015-11-23T09:07:08

You can remove the event filter entirely. You need to resize the widget when the items are expanded or collapsed. Both actions trigger signals, so you can simply connect those signals to resize:

class TreeWidget(QTreeWidget):
    def __init__(self, parent=None):
        super(TreeWidget, self).__init__(parent)
        self.expanded.connect(self.resize)
        self.collapsed.connect(self.resize)

qtreewidget unwanted white space (additional unremovable rows)

1 Answers