我如何在pyqt中连接三个或多个窗口

Question

我有一个复杂的程序，需要在其中连接多个窗口。不幸的是，我似乎并不完全了解执行此操作所需的概念/步骤，因此如果有人可以很好地解释步骤/过程，则可以进行奖励。在我当前的程序中，我有一个项目列表。一旦我通过将它们移到正确的列表小部件来选择它们后，我就需要将它们转到第三个窗口。应通过单击第二个窗口上的点来激活第三个窗口。该程序运行并适当显示第二个窗口，但点按钮的信号/插槽连接不起作用。但是，其余的代码正在工作，因为如果我切换工具包以显示第三个窗口，则该部分的执行量按预期执行。我的代码在下面，再次没有返回错误，但是单击第二个窗口上的点按钮无济于事。

另外，一个问题 - 我是在第二类内还是仅在主窗口内实例化的第三个窗口？同样，努力充分理解该过程，我需要多次进行此操作。

from PyQt5.QtWidgets import QApplication, QWidget, QLabel, QPushButton, QListWidget, QLineEdit, QTextEdit, QGridLayout, QHBoxLayout, QVBoxLayout, QSizePolicy, QFileDialog, QTabWidget, QCheckBox
import PyQt5.QtGui as qtg
import glob
import os
from PyQt5.QtCore import Qt, QSettings
import inspect
from PyQt5 import QtCore
import pandas as pd 
import pathlib
import pyreadstat
import json


class ThirdWindow(QWidget):
    def __init__(self):
        super().__init__()
        
        
        self.layout = QGridLayout()
        self.setLayout(self.layout)
        self.allVariables = QListWidget()
        self.variablesSelected = QListWidget()
        #self.allVariables.insertItem(0, 'Hello')
        self.layout.addWidget(self.allVariables, 1,0)
        self.layout.addWidget(self.variablesSelected, 1, 1)
        
    def setItems(self, items):
        self.allVariables.clear()
        for item in items:
            self.allVariables.addItem(item)
     
    
     
class SecondWindow(QWidget):
    def __init__(self):
        super().__init__()
        
        ##not sure if I am supposed to instantiate this here or only in the main window class
        self.thirdWindow = ThirdWindow()
        
    
        self.layout = QGridLayout(self)
        self.by = QLabel("By")
        self.byVariables = QLineEdit()
        self.byButton = QPushButton("...")
        self.layout.addWidget(self.by, 1, 0)
        self.layout.addWidget(self.byVariables, 2, 0)
        self.layout.addWidget(self.byButton, 2, 1)
        
       
    def seconddWindowConnections(self):
        self.byButton.clicked.connect(self.show_third_window)
        #self.buttons['Toolkit'].clicked.connect(self.show_new_window)   
        
    def show_third_window(self):
        self.thirdWindow.show()
        
class MainWindow(QWidget):
    def __init__(self):
        super().__init__()

        # Add a title
        self.setWindowTitle("GUI Querying Program")

        self.layout = QHBoxLayout()
        self.setLayout(self.layout)
        self.initUI()
        self.setButtonConnections()
        
        self.sw = SecondWindow()
        self.tw = ThirdWindow()
        

    def initUI(self):
        subLayouts = {}

        subLayouts['LeftColumn'] = QGridLayout()
    
        self.layout.addLayout(subLayouts['LeftColumn'],1)
        
        # Buttons
        self.buttons = {}
        self.buttons['addVariable'] = QPushButton('>')
        self.buttons['removeVariable'] = QPushButton('<')
        self.buttons['Toolkit'] = QPushButton('Toolkit')
        
        
        self.variables = QListWidget()
        self.selectedVariables = QListWidget()
        
        subLayouts['LeftColumn'].addWidget(self.variables, 7,0,4,1)
        subLayouts['LeftColumn'].addWidget(self.selectedVariables, 7,1,4,1)
        subLayouts['LeftColumn'].addWidget(self.buttons['addVariable'], 10,0,1,1)
        subLayouts['LeftColumn'].addWidget(self.buttons['removeVariable'], 10,1,1,1)
        subLayouts['LeftColumn'].addWidget(self.buttons['Toolkit'], 11,1,1,1)
        
        names = ['apple', 'banana', 'Cherry']
        self.variables.insertItems(0, names)
        
    def setButtonConnections(self):
        self.buttons['addVariable'].clicked.connect(self.add_variable)
        self.buttons['Toolkit'].clicked.connect(self.show_new_window)   
        self.buttons['Toolkit'].clicked.connect(self.add_selected_variables)
        
    def add_variable(self):
        for item in self.variables.selectedItems():
            self.selectedVariables.addItem(item.clone())

    def show_new_window(self):
        self.sw.show()
        
    def add_selected_variables(self):
        items = []
        for i in range(self.selectedVariables.count()):
            items.append(self.selectedVariables.item(i).clone())
        self.tw.setItems(items)


if __name__ == "__main__":
    import sys
    app = QApplication([])
    mw = MainWindow()
    mw.show()
    app.exec()

Answer 1

代码的主要问题是secondWindowConnections从未调用，因此该按钮实际上无能为力。我对此进行了更正，并修复了下面的示例中发现的其他一些问题。我忽略了我没有做出任何更改的地方，我做了所有的更改，我对它们进行了内联说明：

class SecondWindow(QWidget):
    def __init__(self):
        super().__init__()
        self.thirdWindow = None  # dont initialize until neccessary
        self.thirdWindowItems = []
        self.layout = QGridLayout(self)
        self.by = QLabel("By")
        self.byVariables = QLineEdit()
        self.byButton = QPushButton("...")
        self.layout.addWidget(self.by, 1, 0)
        self.layout.addWidget(self.byVariables, 2, 0)
        self.layout.addWidget(self.byButton, 2, 1)
        self.secondWindowConnections()  #  Run this to setup the
                                       #  signal for the third window.
    def secondWindowConnections(self):   # this had a typo
        self.byButton.clicked.connect(self.show_third_window)

    def show_third_window(self):
        if self.thirdWindow is None:           # if window has been created yet
            self.thirdWindow = ThirdWindow()   # create window
        if not self.thirdWindow.isVisible():   # if window is showing
            self.thirdWindow.show()            # show window
        self.thirdWindow.setItems(self.thirdWindowItems)  # send items to window

    def send_items(self, items):       # this is to collect the variable that
        self.thirdWindowItems = items  # move to the third window

class MainWindow(QWidget):
    def __init__(self):
        super().__init__()
        # Add a title
        self.setWindowTitle("GUI Querying Program")
        self.layout = QHBoxLayout()
        self.setLayout(self.layout)
        self.initUI()
        self.setButtonConnections()
        self.sw = None    # dont initialize until neccessary.

    def initUI(self):
        subLayouts = {}
        subLayouts['LeftColumn'] = QGridLayout()
        self.layout.addLayout(subLayouts['LeftColumn'],1)
        self.buttons = {}
        self.buttons['addVariable'] = QPushButton('>')
        self.buttons['removeVariable'] = QPushButton('<')
        self.buttons['Toolkit'] = QPushButton('Toolkit')
        self.variables = QListWidget()
        self.selectedVariables = QListWidget()
        subLayouts['LeftColumn'].addWidget(self.variables, 7,0,4,1)
        subLayouts['LeftColumn'].addWidget(self.selectedVariables, 7,1,4,1)
        subLayouts['LeftColumn'].addWidget(self.buttons['addVariable'], 10,0,1,1)
        subLayouts['LeftColumn'].addWidget(self.buttons['removeVariable'], 10,1,1,1)
        subLayouts['LeftColumn'].addWidget(self.buttons['Toolkit'], 11,1,1,1)
        names = ['apple', 'banana', 'Cherry']
        self.variables.insertItems(0, names)

    def setButtonConnections(self):
        self.buttons['addVariable'].clicked.connect(self.add_variable)
        self.buttons['Toolkit'].clicked.connect(self.show_new_window)
        # self.buttons['Toolkit'].clicked.connect(self.add_selected_variables)
        # only use one connnect slot

    def add_variable(self):
        for item in self.variables.selectedItems():
            self.selectedVariables.addItem(item.clone())

    def show_new_window(self):     
        if self.sw is None:   #  check if window has been constructed
            self.sw = SecondWindow()  # construct window
        if not self.sw.isVisible():    #  If winow is not showing
            self.sw.show()         #  show window
        self.sw.send_items(self.add_selected_variables())   # send selected 
                                                            # variables to second window

    def add_selected_variables(self):
        items = []
        for i in range(self.selectedVariables.count()):
            items.append(self.selectedVariables.item(i).clone())
        # self.tw.setItems(items) ...  self.tw doesnt exist so return them
        return items