pyqt4按钮单击事件打开新框架/窗口

Question

I am a newbie to Python GUI programming. Currently I am trying to create buttons where once I clicked on it, it should open a new window/frame.

This is my python GUI code:

class Window(QtGui.QMainWindow):
    def __init__(self):
        super(Window, self).__init__()
        palette = QPalette()
        palette.setBrush(QPalette.Background,QBrush(QPixmap("blue-gradient-2.jpg")))
        self.setPalette(palette)

        self.setGeometry(300, 300, 600, 400)
        self.setWindowTitle("Testing Window")
        # self.setWindowIcon(QtGui.QIcon(''))
        self.home()


    def qr(self):
        backbtn = QtGui.QPushButton("Back" , self)
        backbtn.clicked.connect(home)
        backbtn.resize(100, 100)
        backbtn.move(100, 100)
        self.show()

    def home(self):
        btn = QtGui.QPushButton("QR Code", self)
        btn.clicked.connect(qr)

        btn.resize(100, 100)
        btn.move(100, 100)

        btn1 = QtGui.QPushButton("Face Recognition", self)
        btn1.clicked.connect(QtCore.QCoreApplication.instance().quit)

        btn1.resize(200, 100)
        btn1.move(300, 100)

        self.show()


def run():
    app = QtGui.QApplication(sys.argv)
    GUI = Window()
    sys.exit(app.exec_())

run()

Actually, this code I took from a tutorial. I saw even Tkinter can open a new window/frame. But there isn't any tutorial on the PyQt opening a new window/frame.

The error I am getting is:

 Traceback (most recent call last):
  File "pyqt.py", line 47, in <module>
    run()
  File "pyqt.py", line 44, in run
    GUI = Window()
  File "pyqt.py", line 16, in __init__
    self.home()
  File "pyqt.py", line 28, in home
    btn.clicked.connect(qr)
NameError: global name 'qr' is not defined

I am sure there should be a appropriate way to deal with this error.

Answer 1

Your problem is, that you haven't defined a global function qr() . But since you have defined a method with the same name, I suspect your intention was to do

btn.clicked.connect(self.qr)

The same accounts for home() in your qr method

backbtn.clicked.connect(self.home)

To open a new window with PyQt4 it is as easy as calling widget.show() on a widget without a parent.