经常有人问到如何在一个主窗口中打开一个对话框，然后在确认对话框之后，开启另一个窗口进行后续操作，

要求主窗口和最终的窗口之间都能响应用户操作，也就是非模态窗口。随手写了几行代码，简要示意。

:::python

#!/usr/bin/python

# -*- coding: utf-8 -*-

# Gui (imgui@qq.com)

# License: BSD

from PyQt4.QtCore import *

from PyQt4.QtGui import *

import sys

class W1(QWidget):

def __init__(self, parent=None):

super(W1, self).__init__(parent)

self.btn = QPushButton('Click1')

vb = QVBoxLayout()

vb.addWidget(self.btn)

self.setLayout(vb)

self.btn.clicked.connect(self.fireupWindows2)

def fireupWindows2(self):

w2 = W2()

if w2.exec_():

self.w3 = W3() # 需要通过self实例化为全局变量，不加self的话，一运行就被回收，也就无法显示。

self.w3.show()

class W2(QDialog):

def __init__(self, parent=None):

super(W2, self).__init__(parent)

self.btn = QPushButton('Click2')

vb = QVBoxLayout()

vb.addWidget(self.btn)

self.setLayout(vb)

self.btn.clicked.connect(self.fireupWindows3)

def fireupWindows3(self):

self.accept()

class W3(QWidget):

def __init__(self, parent=None):

super(W3, self).__init__(parent)

self.resize(300, 300)

self.btn = QLabel('The Last Window')

vb = QVBoxLayout()

vb.addWidget(self.btn)

self.setLayout(vb)

if __name__ == "__main__":

app = QApplication(sys.argv)

w = W1()

w.show()

sys.exit(app.exec_())

oneMainWindow.py

# -*- coding:utf-8 -*-

from PyQt4.QtGui import (QMainWindow, QPushButton, QApplication,

QVBoxLayout, QWidget)

from PyQt4.QtCore import (Qt, QObject, SIGNAL)

import anotherWindow

import sys

class OneWindow(QMainWindow):

def __init__(self):

super(OneWindow, self).__init__()

self.setGeometry(100, 100, 600, 400)

vLayout = QVBoxLayout()

self.button = QPushButton("OK")

vLayout.addWidget(self.button)

widget = QWidget()

widget.setLayout(vLayout)

self.setCentralWidget(widget)

QObject.connect(self.button,SIGNAL("clicked()") , self.anotherWindow)

def anotherWindow(self):

print 'OK'

self.another = anotherWindow.AnotherWindow()

self.another.show()              #难道不是用这个show()函数吗？

if __name__ == '__main__':

app = QApplication(sys.argv)

w = OneWindow()

w.show()

app.exec_()

anotherWindow.py

# -*- coding:utf-8 -*-

from PyQt4.QtGui import (QMainWindow)

class AnotherWindow(QMainWindow):

def __init__(self):

super(AnotherWindow, self).__init__()

self.resize(400, 300)

self.setWindowTitle("this is another window")