Check An Item That Effects On A Certain Set Of Items Within Qlistwidget

I have a list of items that I have created and added into the QListWidget in which these items are 'categorized'. In my following code, I have 2 categories - -- All Nums -- and --

Solution 1:

The solution idea is to use a role to store the information if the item is a category or not, and another role that indicates the parentship between the items, and then modify if they meet the requirement using a delegate for it.

from PyQt4 import QtCore, QtGui


IsCategoryRole = QtCore.Qt.UserRole
ParentRole = QtCore.Qt.UserRole + 1


class CategoryDelegate(QtGui.QStyledItemDelegate):
    def editorEvent(self, event, model, option, index):
        old_state = model.data(index, QtCore.Qt.CheckStateRole)
        res = super(CategoryDelegate, self).editorEvent(
            event, model, option, index
        )
        current_state = model.data(index, QtCore.Qt.CheckStateRole)
        if old_state != current_state:
            if index.data(IsCategoryRole):
                pix = QtCore.QPersistentModelIndex(index)
                for i in range(model.rowCount()):
                    ix = model.index(i, 0)
                    if pix == ix.data(ParentRole):
                        model.setData(
                            ix, current_state, QtCore.Qt.CheckStateRole
                        )
        return res


class ListWidget(QtGui.QListWidget):
    def __init__(self, parent=None):
        super(ListWidget, self).__init__(parent)
        delegate = CategoryDelegate(self)
        self.setItemDelegate(delegate)

    def addCategory(self, text):
        item = ListWidget.create_checkable_item(text)
        item.setData(IsCategoryRole, True)
        self.addItem(item)
        return item

    def addItemToCategory(self, category_item, text):
        item = ListWidget.create_checkable_item(text)
        item.setData(IsCategoryRole, False)
        ix = self.indexFromItem(category_item)
        pix = QtCore.QPersistentModelIndex(ix)
        item.setData(ParentRole, pix)
        self.addItem(item)
        return item

    @staticmethod
    def create_checkable_item(text):
        item = QtGui.QListWidgetItem(text)
        item.setFlags(
            item.flags()
            | QtCore.Qt.ItemIsUserCheckable
            | QtCore.Qt.ItemIsEditable
        )
        item.setCheckState(QtCore.Qt.Unchecked)
        return item


class TestDialog(QtGui.QDialog):
    def __init__(self, parent=None):
        super(TestDialog, self).__init__()
        self.listWidget = ListWidget()

        all_num = self.listWidget.addCategory("-- All Nums --")
        num_items = ["One", "Two", "Three"]
        for num in num_items:
            self.listWidget.addItemToCategory(all_num, num)

        all_letters = self.listWidget.addCategory("-- All Letters --")

        letter_items = ["One", "Two", "Three"]
        for letter in letter_items:
            self.listWidget.addItemToCategory(all_letters, letter)

        layout = QtGui.QVBoxLayout(self)
        layout.addWidget(self.listWidget)


if __name__ == "__main__":
    import sys

    app = QtGui.QApplication(sys.argv)
    w = TestDialog()
    w.show()
    sys.exit(app.exec_())