安装PySide2

输入pip install PySide2安装Qt for Python，如果安装过慢需要翻墙，则可以使用国内清华镜像下载，输入命令pip install --user -i https://pypi.tuna.tsinghua.edu.cn/simple PySide2，如下图，

示例Demo

import random
import sys

from PySide2 import QtCore, QtWidgets, QtGui


class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()

        self.hello = ["您已点击1次", "您已点击2次", "您已点击3次", "您已点击4次"]

        self.button = QtWidgets.QPushButton("请点击按钮")
        self.text = QtWidgets.QLabel("测试用户界面")
        self.text.setAlignment(QtCore.Qt.AlignCenter)

        self.layout = QtWidgets.QVBoxLayout()
        self.layout.addWidget(self.text)
        self.layout.addWidget(self.button)
        self.setLayout(self.layout)

        self.button.clicked.connect(self.magic)

    def magic(self):
        self.text.setText(random.choice(self.hello))


if __name__ == "__main__":
    app = QtWidgets.QApplication([])
    widget = MyWidget()
    widget.resize(600, 400)
    widget.show()
    sys.exit(app.exec_())

可能报错如下，

Class QMacAutoReleasePoolTracker is implemented in both xxx and xxx. One of the two will be used. Which one is undefined.

该原因是mac版本下安装的opencv包包含一些qt的头文件与PyQt5冲突了，导致无法正确导入相应的包。

输入命令pip uninstall xxx卸载掉冲突的包即可。最后输出UI界面。