In PyQt I want to use a QAbstractItemModel and QDataWidgetMapper to map widgets to the model data. For QLineEdit it works fine, but I want to have a mapping between a QButtonGroup (filled with several QRadioButton) and the model. Therefore I subclassed QGroupBox and added a custom property selectedOption:
class ButtonGroupWidget(QGroupBox):
def __init__(self, parent=None):
super(ButtonGroupWidget, self).__init__(parent)
self._selectedOption = -1
self.buttonGroup = QButtonGroup()
self.layoutGroupBox = QVBoxLayout(self)
def addRadioButton(self,optionText,optionId):
print(optionText)
radioButton = QRadioButton(optionText)
radioButton.clicked.connect(self.updateOptionSelected)
self.layoutGroupBox.addWidget(radioButton)
self.buttonGroup.addButton(radioButton,optionId)
def updateOptionSelected(self):
print(self.buttonGroup.checkedId()) # for test purpose
self.selectedOption = self.buttonGroup.checkedId()
print(self._selectedOption) # for test purpose
def getSelectedOption(self):
print("get selectedOption is called")
return self._selectedOption
def setSelectedOption(self,selectedOption):
print("set selectedOption is called")
self._selectedOption = selectedOption
self.buttonGroup.button(selectedOption).setChecked(True)
selectedOption = pyqtProperty(int,getSelectedOption,setSelectedOption)
In the main widget I create an instance of this ButtonGroupWidget:
class MainWidget(QWidget):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
...
# insert a button group widget
self.buttonGroupWidget1 = ButtonGroupWidget(self)
self.buttonGroupWidget1.setTitle("Select option")
self.buttonGroupWidget1.addRadioButton("Option 1", 1)
self.buttonGroupWidget1.addRadioButton("Option 2", 2)
self.buttonGroupWidget1.addRadioButton("Option 3", 3)
...
# Create the data model and map the model to the widgets.
self._model = DataModel()
...
self._dataMapper = QDataWidgetMapper()
self._dataMapper.setModel(self._model)
...
# mapping to custom property
self._dataMapper.addMapping(self.buttonGroupWidget1,1,"selectedOption")
The full code (working minimal example) is given below. My problem is the following: If the model is changed (for example by the lineEdit you see in the full code), the setSelectedOption method is called and self._selectedOption is set to the current value and the radioButtons are updated. But if I click on another radioButton, I do not know how to update the model.
Is there something like a data changed event for the QWidget, that will update the model?
Is there a better way to map a QAbstractItemModel to a GroupBox with a number of radioButtons?
full code (minimal example, tested with Python 3.4 and PyQt 5.4):
import sys
from PyQt5.QtWidgets import QWidget, QLineEdit, QRadioButton, QButtonGroup, QApplication, QVBoxLayout, QGroupBox, QTreeView,QDataWidgetMapper
from PyQt5.QtCore import QAbstractItemModel,QModelIndex,Qt,pyqtProperty
"""Base class to provide some nodes fro a tree
At the moment each node contains two members: name and option"""
class Node(object):
def __init__(self,name,parent=None):
self._name = name
self._children = []
self._parent = parent
self._option = 2
if parent is not None:
parent.addChild(self)
def name(self):
return self._name
def setName(self, name):
self._name = name
def option(self):
return self._option
def setOption(self,option):
self._option = option
def addChild(self,child):
self._children.append(child)
def insertChild(self, position, child):
if position < 0 or position > len(self._children):
return False
self._children.insert(position, child)
child._parent = self
return True
def removeChild(self, position):
if position < 0 or position > len(self._children):
return False
child = self._children.pop(position)
child._parent = None
return True
def child(self,row):
return self._children[row]
def childCount(self):
return len(self._children)
def parent(self):
return self._parent
def row(self):
if self._parent is not None:
return self._parent._children.index(self)
def __repr__(self):
return self.log()
class ButtonGroupWidget(QGroupBox):
def __init__(self, parent=None):
super(ButtonGroupWidget, self).__init__(parent)
self._selectedOption = -1
self.buttonGroup = QButtonGroup()
self.layoutGroupBox = QVBoxLayout(self)
def addRadioButton(self,optionText,optionId):
print(optionText)
radioButton = QRadioButton(optionText)
radioButton.clicked.connect(self.updateOptionSelected)
self.layoutGroupBox.addWidget(radioButton)
self.buttonGroup.addButton(radioButton,optionId)
def updateOptionSelected(self):
print(self.buttonGroup.checkedId()) # for test purpose
self.selectedOption = self.buttonGroup.checkedId()
print(self._selectedOption) # for test purpose
def getSelectedOption(self):
print("get selectedOption is called")
return self._selectedOption
def setSelectedOption(self,selectedOption):
print("set selectedOption is called")
self._selectedOption = selectedOption
self.buttonGroup.button(selectedOption).setChecked(True)
selectedOption = pyqtProperty(int,getSelectedOption,setSelectedOption)
class DataModel(QAbstractItemModel):
def __init__(self, parent=None):
super(DataModel, self).__init__(parent)
self._rootNode = Node("Root Node")
childNode1 = Node("Child 1",self._rootNode)
childNode2 = Node("Child 2",self._rootNode)
childNode3 = Node("Child 3",self._rootNode)
def __eq__(self, other):
return self.__dict__ == other.__dict__
def isNull(self):
nullObject = DataModel()
if self.__eq__(nullObject):
return True
else:
return False
def rowCount(self, parent):
if not parent.isValid():
parentNode = self._rootNode
else:
parentNode = parent.internalPointer()
return parentNode.childCount()
def columnCount(self, parent):
return 1
def data(self,index,role):
if not index.isValid():
return None
node = index.internalPointer()
if role == Qt.DisplayRole or role == Qt.EditRole:
if index.column() == 0:
return node.name()
if index.column() == 1:
return node.option()
def setData(self,index,value, role=Qt.EditRole):
if index.isValid():
node = index.internalPointer()
if role == Qt.EditRole:
if index.column() == 0:
node.setName(value)
if index.column() == 1:
node.setOption(value)
self.dataChanged.emit(index,index)
return True
return False
def headerData(self, section, orientation, role):
if role == Qt.DisplayRole:
if section == 0:
return "Select Child"
def flags(self, index):
return Qt.ItemIsEnabled | Qt.ItemIsSelectable | Qt.ItemIsEditable
def parent(self, index):
node = index.internalPointer()
parentNode = node.parent()
if parentNode == self._rootNode:
return QModelIndex()
return self.createIndex(parentNode.row(), 0, parentNode)
def index(self, row, column, parent):
if not parent.isValid():
parentNode = self._rootNode
else:
parentNode = parent.internalPointer()
childItem = parentNode.child(row)
if childItem:
return self.createIndex(row, column, childItem)
else:
return QModelIndex()
def getNode(self, index):
if index.isValid():
node = index.internalPointer()
if node:
return node
return self._rootNode
class MainWidget(QWidget):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
# define tree view
self.treeView = QTreeView(self)
# insert line edit
self.lineEdit1 = QLineEdit(self)
self.lineEdit2 = QLineEdit(self)
# insert a button group widget
self.buttonGroupWidget1 = ButtonGroupWidget(self)
self.buttonGroupWidget1.setTitle("Select option")
self.buttonGroupWidget1.addRadioButton("Option 1", 1)
self.buttonGroupWidget1.addRadioButton("Option 2", 2)
self.buttonGroupWidget1.addRadioButton("Option 3", 3)
layoutMain = QVBoxLayout(self)
layoutMain.addWidget(self.treeView)
layoutMain.addWidget(self.lineEdit1)
layoutMain.addWidget(self.lineEdit2)
layoutMain.addWidget(self.buttonGroupWidget1)
# Create the data model and map the model to the widgets.
self._model = DataModel()
self.treeView.setModel(self._model)
self._dataMapper = QDataWidgetMapper()
self._dataMapper.setModel(self._model)
# the mapping works fine for line edits and combo boxes
self._dataMapper.addMapping(self.lineEdit1, 0)
self._dataMapper.addMapping(self.lineEdit2, 1)
# mapping to custom property
self._dataMapper.addMapping(self.buttonGroupWidget1,1,"selectedOption")
self.treeView.selectionModel().currentChanged.connect(self.setSelection)
def setSelection(self, current):
parent = current.parent()
self._dataMapper.setRootIndex(parent)
self._dataMapper.setCurrentModelIndex(current)
def main():
app = QApplication(sys.argv)
form = MainWidget()
form.show()
app.exec_()
main()
The model will be updated when the radio-button option changes, but only if return or enter is pressed.
The reason for this, is that the data-mapper uses an item-delegate to notify changes to the model, and this item-delegate installs an event-filter on every widget that is mapped. But the event-filter only monitors key-presses and focus-changes, not mouse-clicks, and in any case, it cannot receive events from child widgets.
A mildly hackish way to work around this limitation is to simulate an appropriate key-press whenever a radio button is clicked: