PyQt5-多窗口數據傳輸

#窗口之間數據傳遞（通過屬性方式）
from PyQt5.QtWidgets import QDialogButtonBox, QDateTimeEdit,QDialog,QComboBox,QTableView,QAbstractItemView,QHeaderView,QTableWidget, QTableWidgetItem, QMessageBox,QListWidget,QListWidgetItem, QStatusBar,  QMenuBar,QMenu,QAction,QLineEdit,QStyle,QFormLayout,   QVBoxLayout,QWidget,QApplication ,QHBoxLayout, QPushButton,QMainWindow,QGridLayout,QLabel
from PyQt5.QtGui import QIcon,QPixmap,QStandardItem,QStandardItemModel,QCursor,QFont,QBrush,QColor,QPainter,QMouseEvent,QImage,QTransform
from PyQt5.QtCore import QStringListModel,QAbstractListModel,QModelIndex,QSize,Qt,QObject,pyqtSignal,QTimer,QEvent,QDateTime,QDate

import sys
class Win(QWidget):
    def __init__(self,parent=None):
        super(Win, self).__init__(parent)
        self.resize(400,400)

        self.btn=QPushButton("按鈕",self)
        self.btn.move(50,50)
        self.btn.setMinimumWidth(120)
        self.btn.clicked.connect(self.openDialog)

        #顯示子窗口傳來的日期字符串或者其他數據
        self.label=QLabel('這里顯示信息',self)
        self.label.setMinimumWidth(420)

    #打開Dialog
    def openDialog(self):
        dialog=Dialog(self)
        #連接【子窗口內置消息和主窗口的槽函數】
        dialog.datetime.dateChanged.connect(self.slot_inner)
        #連接【子窗口自定義消息和主窗口槽函數】
        dialog.dialogSignel.connect(self.slot_emit)
        dialog.show()

    def slot_inner(self,date):
        print("主窗口：method_1")
        self.label.setText("①"+str(date)+">>內置消息獲取日期為")


    def slot_emit(self,flag,str):
        print("主窗口：method_2")
        print(flag)
        if flag=="0":#點擊ok
          self.label.setText("②"+str(str)+">>自定義消息")
        else:#點擊cancel
          self.label.setText(str)

#彈出框對象
class Dialog(QDialog):
    #自定義消息
    dialogSignel=pyqtSignal(int,str)

    def __init__(self,parent=None):
        super(Dialog, self).__init__(parent)
        layout=QVBoxLayout(self)
        self.label=QLabel(self)
        self.datetime=QDateTimeEdit(self)
        self.datetime.setCalendarPopup(True)
        self.datetime.setDateTime(QDateTime.currentDateTime())
        self.label.setText("請選擇日期")
        layout.addWidget(self.label)
        layout.addWidget(self.datetime)

        buttons=QDialogButtonBox(QDialogButtonBox.Ok|QDialogButtonBox.Cancel,Qt.Horizontal,self)
        buttons.accepted.connect(self.accept)#點擊ok
        buttons.rejected.connect(self.reject)#點擊cancel
        layout.addWidget(buttons)
    def accept(self):#點擊ok是發送內置信號
        print("accept")
        self.dialogSignel.emit(0,self.datetime.text())
        self.destroy()
    def reject(self):#點擊cancel時，發送自定義信號
        print('reject')
        self.dialogSignel.emit(1,"清空")
        self.destroy()


if __name__=='__main__':

    app=QApplication(sys.argv)
    win = Win()
    win.show()
    sys.exit(app.exec_())