import sys
from PyQt5.QtWidgets import QTreeWidgetItem, QTreeWidget, QWidget, QVBoxLayout, QPushButton, QApplication
from PyQt5.QtCore import Qt


class Demo(QWidget):
    def __init__(self):
        super().__init__()
        # 實例化一個樹形結構，隱藏了header
        self.tree = QTreeWidget()
        self.tree.setHeaderHidden(True)
        # 頂級分支
        self.tree_main = QTreeWidgetItem(self.tree)
        self.tree_main.setText(0, '商品種類')
        # 設置一些二級分支
        tree_second = ['電子產品', '水果', '日用品', '喜歡的人']
        self.gen_branch(self.tree_main, tree_second)
        # 設置一些三級分支
        tree_fruit = ['蘋果', '香蕉', '梨']
        tree_daily_use = ['紙巾', '毛巾']
        tree_lovers = ['迪迪1號', '迪迪2號']
        # child(1) 意思是分支的第1個節(jié)點, 序號從0算起
        self.gen_branch(self.tree_main.child(1), tree_fruit)
        self.gen_branch(self.tree_main.child(2), tree_daily_use)
        self.gen_branch(self.tree_main.child(3), tree_lovers)
        # 一個按鈕
        self.pushButton = QPushButton('選好了')
        # 顯示出來
        self.qvl = QVBoxLayout()
        self.qvl.addWidget(self.tree)
        self.qvl.addWidget(self.pushButton)
        self.setLayout(self.qvl)

        # 綁定一下槽函數，傳入主要的分支節(jié)點
        self.pushButton.clicked.connect(lambda: self.get_checked(self.tree_main))

    @staticmethod
    def gen_branch(node: QTreeWidgetItem, texts: list):
        """ 給定某個節(jié)點和列表 在該節(jié)點生成列表內分支"""
        for text in texts:
            item = QTreeWidgetItem()
            item.setText(0, text)
            item.setCheckState(0, Qt.Unchecked)
            node.addChild(item)

    def get_checked(self, node: QTreeWidgetItem)->list:
        """ 得到當前節(jié)點選中的所有分支， 返回一個 list """
        temp_list = []
        # 此處看下方注釋 1
        for item in node.takeChildren():
            # 判斷是否選中
            if item.checkState(0) == Qt.Checked:
                temp_list.append(item.text(0))
                # 判斷是否還有子分支
                if item.childCount():
                    temp_list.extend(self.get_checked(item))
            node.addChild(item)
        print(temp_list)
        return temp_list


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

[
<PyQt5.QtWidgets.QTreeWidgetItem object at 0x0000000008464708>, 
<PyQt5.QtWidgets.QTreeWidgetItem object at 0x0000000008464798>, 
]

item = QtWidgets.QTreeWidgetItemIterator(self.treeWidget)，

self.item1 = QTreeWidgetItem()

self.item_list = []
self.item_list.append([... ... ])