pyqt5给treewidget获取点击项的序号

可以通过`currentItem()`方法获取当前被选中（点击）的项，然后再通过`indexOfTopLevelItem()`或者`indexOfChild()`方法获取该项在顶级项或子项中的序号。下面是一个示例代码：

from PyQt5.QtWidgets import QApplication, QTreeWidget, QTreeWidgetItem
import sys

class TreeWidget(QTreeWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        
        # 添加顶级项
        top_items = [QTreeWidgetItem(['Item {}'.format(i)]) for i in range(1, 6)]
        self.addTopLevelItems(top_items)
        
        # 添加子项
        for i in range(5):
            child_items = [QTreeWidgetItem(['Item {}.{}'.format(i+1, j+1)]) for j in range(3)]
            top_items[i].addChildren(child_items)
        
        # 设置信号槽
        self.itemClicked.connect(self.on_item_clicked)
        
    def on_item_clicked(self, item, column):
        # 获取当前点击项在顶级项或子项中的序号
        if item.parent() is None:
            index = self.indexOfTopLevelItem(item)
            print('Clicked top item {}: {}'.format(index, item.text(column)))
        else:
            parent = item.parent()
            index = parent.indexOfChild(item)
            top_index = self.indexOfTopLevelItem(parent)
            print('Clicked child item {}.{}: {}'.format(top_index, index, item.text(column)))

if __name__ == '__main__':
    app = QApplication(sys.argv)
    treeWidget = TreeWidget()
    treeWidget.show()
    sys.exit(app.exec_())

当点击某个项时，会在控制台输出该项在顶级项或子项中的序号和文本内容。例如，当点击顶级项`Item 3`时，会输出：

Clicked top item 2: Item 3

当点击该项下的子项`Item 3.2`时，会输出：

Clicked child item 2.2: Item 3.2