validating specific column of QTreeWidget using QStyledItemDelegate not working properly - python-3.x

Question

I have a QTreeWidget with 3 columns, only the 3rd column should have a double validator. My issue is that it somewhat works; The QLineEdit does not stop at 100 it just keeps going.
what I am missing; to make it where it doesn't let user input anything higher than 100 while still editing the lineEdit?
import sys
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import *
class Delegate(QStyledItemDelegate):
'Changes number of decimal places in gas analysis self.chosen table'
def __init__(self, decimals, parent=None):
super().__init__(parent)
self.nDecimals = decimals
def createEditor(self, parent, option, index):
editor = QLineEdit(parent)
editor.setValidator(QDoubleValidator(0,100, 15))
return editor
def setEditorData(self, editor, index):
if index.column() == 2 and index.data() is not None:
editor.setText(str(float(index.data())))
class Widget(QMainWindow):
def __init__(self, parent=None):
QMainWindow.__init__(self, parent=None)
self.tree_widget = QTreeWidget()
self.tree_widget.setItemDelegate(Delegate(self.tree_widget))
self.tree_widget.setHeaderLabels(["Value1", "Value2", "Value3"])
self.setCentralWidget(self.tree_widget)
for vals in [("h", "20.0", "40.0"), ("k", "25.0", "50.0")]:
it = QTreeWidgetItem(vals)
it.setFlags(it.flags()| Qt.ItemIsEditable)
self.tree_widget.addTopLevelItem(it)
if __name__ == '__main__':
app = QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())

Answer 1

The QDoubleValidator only tries to validate the text entered by the user, if it does not meet the requirement then the information will not be saved and that is what is observed in your case. If you want to define what values you want the user to use in your specific case, it is better to use the QDoubleSpinBox as editor:
class Delegate(QStyledItemDelegate):
def __init__(self, decimals, parent=None):
super().__init__(parent)
self.nDecimals = decimals
def createEditor(self, parent, option, index):
editor = QDoubleSpinBox(
parent, minimum=0, maximum=100.0, decimals=self.nDecimals
)
return editor
def setEditorData(self, editor, index):
if index.data() is not None:
try:
value = float(index.data())
except Exception as e:
print("error", e)
else:
editor.setValue(value)
class Widget(QMainWindow):
def __init__(self, parent=None):
QMainWindow.__init__(self, parent=None)
self.tree_widget = QTreeWidget()
self.tree_widget.setHeaderLabels(["Value1", "Value2", "Value3"])
self.tree_widget.setItemDelegateForColumn(2, Delegate(15, self.tree_widget))
self.setCentralWidget(self.tree_widget)
for vals in [("h", "20.0", "40.0"), ("k", "25.0", "50.0")]:
it = QTreeWidgetItem(vals)
it.setFlags(it.flags() | Qt.ItemIsEditable)
self.tree_widget.addTopLevelItem(it)
Note: I have modified the column selection since with the initial implementation of the OP the same editor is used in all the columns and that clearly contradicts its same requirement, so instead of using setItemDelegate() I have used setItemDelegateForColumn().