from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QHBoxLayout, QMessageBox
from PyQt5.QtCore import QProcess
import sys

class MyWidget(QWidget):
    def __init__(self):
        super().__init__()
        self.__process = QProcess()
        self.__btn = QPushButton('start notepad')
        self.__init_ui()
        
        # 關(guān)聯(lián)button clicked信號(hào)和對(duì)應(yīng)的槽函數(shù)
        self.__btn.clicked.connect(self.__btn_clicked_handler)
        self.__process.started.connect(self.__process_started_handler)
        self.__process.finished.connect(self.__process_finished_handler)
        
    def __init_ui(self):
        my_layout = QHBoxLayout()
        my_layout.addWidget(self.__btn)
        self.setLayout(my_layout)
        
    def __btn_clicked_handler(self):
        '''
        處理button的clicked信號(hào)，打開notepad.exe
        '''
        self.__process.start('notepad.exe')
        
    def __process_started_handler(self):
        '''
        處理QProcess的started信號(hào)
        '''
        start_msg_box = QMessageBox.information(self, 
                                                'info',
                                                '已成功打開記事本',
                                                QMessageBox.StandardButton.Yes,
                                                QMessageBox.StandardButton.Yes)
        
    def __process_finished_handler(self, exitCode, exitStatus):
        '''
        處理QProcess的finished信號(hào)，獲取退出狀態(tài)
        '''
        
        finished_msg_box = QMessageBox.information(self,
                                                   'info',
                                                   f'記事本已關(guān)閉, exitcode={exitCode}, exitStatus:{exitStatus}',
                                                   QMessageBox.StandardButton.Yes,
                                                   QMessageBox.StandardButton.Yes)
    
if __name__ == '__main__':
    app = QApplication(sys.argv)
    my_widget = MyWidget()
    my_widget.show()
    sys.exit(app.exec_())