PyQt5点击pushbutton在运行时向scrollArea动态添加QLabel的问题

你要实现点击按钮在QScrollArea中动态新增QLabel的需求，现有代码存在两个核心错误：

• 调用QScrollArea.setWidget()会直接替换滚动区域的根承载控件，所以每次点击都会覆盖原有内容，而非新增
• 未将新创建的QLabel添加到滚动区域内容控件已有的垂直布局中，新建的标签无法在原有内容基础上追加展示

你已经在scrollArea的内容控件scrollAreaWidgetContents上绑定了垂直布局verticalLayout，只需要将每次新增的QLabel添加到该布局中即可，修改add_new_label方法如下：

def add_new_label(self):
    new_label = QtWidgets.QLabel()
    new_label.setText("HelloWorld")
    # 追加到已有垂直布局末尾
    self.verticalLayout.addWidget(new_label)
    # 若需要后续操作这些新增标签，可初始化列表存储实例
    # if not hasattr(self, "added_labels"):
    #     self.added_labels = []
    # self.added_labels.append(new_label)

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'test.ui'
#
# Created by: PyQt5 UI code generator 5.9.2
#
# WARNING! All changes made in this file will be lost!

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.scrollArea = QtWidgets.QScrollArea(self.centralwidget)
        self.scrollArea.setGeometry(QtCore.QRect(130, 80, 221, 301))
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Fixed, QtWidgets.QSizePolicy.Fixed)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.scrollArea.sizePolicy().hasHeightForWidth())
        self.scrollArea.setSizePolicy(sizePolicy)
        self.scrollArea.setWidgetResizable(True)
        self.scrollArea.setObjectName("scrollArea")
        self.scrollAreaWidgetContents = QtWidgets.QWidget()
        self.scrollAreaWidgetContents.setGeometry(QtCore.QRect(0, 0, 219, 299))
        self.scrollAreaWidgetContents.setObjectName("scrollAreaWidgetContents")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.scrollAreaWidgetContents)
        self.verticalLayout.setObjectName("verticalLayout")
        self.label = QtWidgets.QLabel(self.scrollAreaWidgetContents)
        self.label.setObjectName("label")
        self.verticalLayout.addWidget(self.label)
        self.label_2 = QtWidgets.QLabel(self.scrollAreaWidgetContents)
        self.label_2.setObjectName("label_2")
        self.verticalLayout.addWidget(self.label_2)
        self.label_3 = QtWidgets.QLabel(self.scrollAreaWidgetContents)
        self.label_3.setObjectName("label_3")
        self.verticalLayout.addWidget(self.label_3)
        self.label_4 = QtWidgets.QLabel(self.scrollAreaWidgetContents)
        self.label_4.setObjectName("label_4")
        self.verticalLayout.addWidget(self.label_4)
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(390, 110, 89, 25))
        self.pushButton.setObjectName("pushButton")
        self.pushButton.clicked.connect(self.button_pressed)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 22))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.label.setText(_translate("MainWindow", "TextLabel"))
        self.label_2.setText(_translate("MainWindow", "TextLabel"))
        self.label_3.setText(_translate("MainWindow", "TextLabel"))
        self.label_4.setText(_translate("MainWindow", "TextLabel"))
        self.pushButton.setText(_translate("MainWindow", "PushButton"))

    def button_pressed(self):
        print("button pressed")
        self.add_new_label()
    
    def add_new_label(self):
        new_label = QtWidgets.QLabel()
        new_label.setText("HelloWorld")
        self.verticalLayout.addWidget(new_label)

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

内容的提问来源于stack exchange，提问作者Mohsin Ali