python - Pyqt5 QTreeWidget CurrentItemChanged 信号发送整数作为前一项

Question

我有一个 QTreeWidget 项和信号 CurrentItemChanged 连接到一个基于数据库查找更新 GUI 的方法。

CurrentItemChanged 文档表示它将把 QTreeWidgetItems 作为参数传递给该方法。首先是当前项目，然后是之前选择的项目。

我看到一个 QTreeWidgetItem 后跟一个整数，可能是当前所选项目的列，而是被传递。此行为似乎不属于任何人的 Pyqt5 文档的一部分。

在我自己存储对上一个项目的引用之前，我是否缺少某些内容？代码简单得令人沮丧:

self.TreeWidget.currentItemChanged.connect(self.update) # signal connect

def update(self, old, new):
    # do stuff with old and new, both as as QTreeWidgetItems

Answer 1

This signal is emitted when the current item changes. The current item is specified by current, and this replaces the previous current item.

尝试一下:

import sys
from PyQt5 import QtWidgets, QtGui, QtCore

class Window(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)
        self.vlayout = QtWidgets.QVBoxLayout()

        # tree widget item
        tree_widget_item = QtWidgets.QTreeWidgetItem(['Item 1'])
        tree_widget_item.addChild(QtWidgets.QTreeWidgetItem(['Sub item 1']))  
        tree_widget_item.addChild(QtWidgets.QTreeWidgetItem(['Sub item 2']))

        # tree widget
        tree_widget = QtWidgets.QTreeWidget(self)
        tree_widget.addTopLevelItem(tree_widget_item)
        self.vlayout.addWidget(tree_widget)

        tree_widget.currentItemChanged.connect(self.current_item_changed)

    @QtCore.pyqtSlot(QtWidgets.QTreeWidgetItem, QtWidgets.QTreeWidgetItem)
    def current_item_changed(self, current, previous):
        print('\ncurrent: {}, \nprevious: {}'.format(current, previous))


application = QtWidgets.QApplication(sys.argv)
window = Window()
window.setWindowTitle('Tree widget')
window.resize(250, 180)
window.show()
sys.exit(application.exec_())