[FIXED] formatting child items in qtreewidget pyqt5

Issue

STYLESHEET = '''QTreeWidget {border:None} 
    QTreeWidget::Item {height: 80px; 
                       border-bottom:2px solid black;
                       color: rgba(255,255,255,255);}   /* +++ */

    QTreeView {
        alternate-background-color: rgba(170,170,170,255);
        background: rgba(211,211,211,255);}'''
self.treeWidget = QTreeWidget()
self.treeWidget.setAlternatingRowColors(True)
self.treeWidget.setStyleSheet(STYLESHEET)

Here I have set the height as 80px in STYLESHEET. But I want to set the height as 40px for child items and 80px for toplevelitem. How do I do that? Thanks in advance

Solution

The Qt Style Sheet are generic, in the case of QTreeWidget there is no selector that differentiates parents and children so the other option is to use a delegate as shown below:

from PyQt5 import QtCore, QtWidgets

STYLESHEET = '''QTreeWidget {border:None} 
    QTreeWidget::Item{
        border-bottom:2px solid black;
        color: rgba(255,255,255,255);
    }
    QTreeView{
        alternate-background-color: rgba(170,170,170,255);
        background: rgba(211,211,211,255);
    }'''


class StyledItemDelegate(QtWidgets.QStyledItemDelegate):
    def sizeHint(self, option, index):
        s = super(StyledItemDelegate, self).sizeHint(option, index)
        if index.parent().isValid():
            s.setHeight(40)
        else:
            s.setHeight(80)
        return s


class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        self.treeWidget = QtWidgets.QTreeWidget()
        delegate = StyledItemDelegate(self.treeWidget)
        self.treeWidget.setItemDelegate(delegate)
        self.treeWidget.setAlternatingRowColors(True)
        self.treeWidget.setStyleSheet(STYLESHEET)
        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(self.treeWidget)
        for i in range(5):
            it = QtWidgets.QTreeWidgetItem(["parent {}".format(i)])
            self.treeWidget.addTopLevelItem(it)
            for j in range(5):
                child = QtWidgets.QTreeWidgetItem(["children {}{}".format(i, j)])
                it.addChild(child)


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())

Answered By - eyllanesc