如何在编辑qlistwidget项后捕获新名称

Question

I have made the items within QListWidget to be editable so that I can perform renaming when needed.

To do the renaming, user can 'double-click' on the item in which it will gives a QLineEdit that enables one to edit the text, and currently I am having issue in capturing the new name after the QLineEdit.

Tried using itemDoubleClicked and currentTextChanged signal but it does not seems to be returning me the new name. For example, I am trying to rename Trhee to Three but under rename_item() , it returns me Trhee

class Dialog(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__()
        self.listWidget = QtGui.QListWidget()
        items = ['One', 'Two', 'Trhee']
        for item in items:
            self.listWidget.addItem(item)

        self.listWidget.currentTextChanged.connect(self.rename_item)
        # self.listWidget.itemDoubleClicked.connect(self.rename_item)

        for index in range(self.listWidget.count()):
            item = self.listWidget.item(index)
            item.setFlags(item.flags() | QtCore.Qt.ItemIsUserCheckable | QtCore.Qt.ItemIsEditable)
            item.setCheckState(QtCore.Qt.Checked)

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

    def rename_item(self):
        prev_item_name = self.listWidget.currentItem()
        print 'before rename: ', prev_item_name.text()

        # Returns me the same value as prev_item_name...
        new_item_name = self.listWidget.currentItem()
        print 'after rename: ', new_item_name.text()


if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    window = Dialog()
    window.setGeometry(600, 100, 300, 200)
    window.show()
    sys.exit(app.exec_())

Answer 1

I;m not exactly sure what are you planning to do. My suggestion is to change activation methods, so for example:

self.listWidget.itemDoubleClicked.connect(self.previous_name)
self.listWidget.itemChanged.connect(self.current_name)

def previous_name(self):
        prev_item_name = self.listWidget.currentItem()
        print ('before rename: ', prev_item_name.text())

def current_name(self):
        try:
            new_item_name = self.listWidget.currentItem()
            print ('after rename: ', new_item_name.text())
        except:
            pass

Answer 2

The appropriate signal for this case is dataChanged but this signal is not only issued when the text is modified, but when other properties, such as the checkbox status, are modified. In PyQt5 / Qt5 is added to that signal an argument that indicates that it allows to distinguish but is not the case of PyQt4.

One way to obtain if the modified role corresponds to the text is to compare the text before and after the change, but the QListWidgetItem only saves one text so another role must be used to save the old text. With this logic I have implemented the following solution:

from PyQt4 import QtCore, QtGui


class ListWidget(QtGui.QListWidget):
    textItemChanged = QtCore.pyqtSignal(QtGui.QListWidgetItem)

    OLDTEXTROLE = QtCore.Qt.UserRole + 1000

    def __init__(self, parent=None):
        super(ListWidget, self).__init__(parent)
        self.model().dataChanged.connect(self.on_data_changed)

    @QtCore.pyqtSlot(QtCore.QModelIndex, QtCore.QModelIndex)
    def on_data_changed(self, topLeft, bottomRight):
        if topLeft == bottomRight:
            it = self.itemFromIndex(topLeft)
            old_text = it.data(ListWidget.OLDTEXTROLE)
            if old_text is None:
                it.setData(ListWidget.OLDTEXTROLE, "")
            if old_text == it.text():
                return
            self.textItemChanged.emit(it)
            it.setData(ListWidget.OLDTEXTROLE, it.text())


class Dialog(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__()
        self.listWidget = ListWidget()
        items = ["One", "Two", "Trhee"]
        for item in items:
            self.listWidget.addItem(item)

        for index in range(self.listWidget.count()):
            item = self.listWidget.item(index)
            item.setFlags(
                item.flags()
                | QtCore.Qt.ItemIsUserCheckable
                | QtCore.Qt.ItemIsEditable
            )
            item.setCheckState(QtCore.Qt.Checked)

        self.listWidget.textItemChanged.connect(self.on_text_item_changed)

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

    @QtCore.pyqtSlot(QtGui.QListWidgetItem)
    def on_text_item_changed(self, it):
        current_text = it.text()
        old_text = it.data(ListWidget.OLDTEXTROLE)
        print("old_text: {}, current_text: {}".format(old_text, current_text))


if __name__ == "__main__":
    import sys

    app = QtGui.QApplication(sys.argv)
    window = Dialog()
    window.setGeometry(600, 100, 300, 200)
    window.show()
    sys.exit(app.exec_())