Pyside2教程：使用QtCore.Signal和QtCore.Slot案例

import sys
from PySide2 import QtWidgets as qtw
from PySide2 import QtGui as qtg
from PySide2 import QtCore as qtc

class FormWindow(qtw.QWidget):
    # 自定义信号，这个信号携带的是string类型的数据。注意str是一个type object
    # 在pyqt中，QtCore.Signal对应的函数为QtCore.pyqtSignal
    # submitted = qtc.Signal(str)
    # 用两个列表表示两种signature。一种只有一个str，另一种有int和str
    submitted = qtc.Signal([str], [int, str])

    def __init__(self):
        super().__init__()
        self.setLayout(qtw.QVBoxLayout())

        self.edit = qtw.QLineEdit()
        self.submit = qtw.QPushButton('提交', clicked=self.onSubmit)

        self.layout().addWidget(self.edit)
        self.layout().addWidget(self.submit)

    @qtc.Slot()
    def onSubmit(self):
        # 调用自定义submitted信号的emit方法来定义信号施放的数据
        if self.edit.text().isdigit():
            text = self.edit.text()
            # 注意这里在signal后面要用[]标记出对应的signature
            self.submitted[int, str].emit(int(text), text)
        else:
            # 注意这里在signal后面要用[]标记出对应的signature
            self.submitted[str].emit(self.edit.text())
        self.close()

# 将主程序封装成类
class MainWindow(qtw.QWidget):
    def __init__(self):
        # 引入父类的__init__方法
        super().__init__(parent=None)
        # Main UI code goes here
        self.setLayout(qtw.QVBoxLayout())

        self.label = qtw.QLabel('点击"变"来改变文字')
        self.change = qtw.QPushButton('变', clicked=self.onChange)

        self.layout().addWidget(self.label)
        self.layout().addWidget(self.change)

        # End main UI code
        # 显示主窗口
        self.show()

    @qtc.Slot()
    def onChange(self):
        self.formwindow = FormWindow()
        # 注意这里在signal后面要用[]标记出对应的signature
        self.formwindow.submitted[str].connect(self.onSubmittedStr)
        # 注意这里在signal后面要用[]标记出对应的signature
        self.formwindow.submitted[int, str].connect(self.onSubmittedIntStr)
        self.formwindow.show()

    @qtc.Slot(str)
    def onSubmittedStr(self, string):
        self.label.setText(string)

    @qtc.Slot(int, str)
    def onSubmittedIntStr(self, integer, string):
        text = 'The string {} becomes the number {}'.format(string, integer)
        self.label.setText(text)

if __name__ == '__main__':
    app = qtw.QApplication()
    main_window = MainWindow()
    sys.exit(app.exec_())