我从http://www.pythoncentral.io/pyside-pyqt-tutorial-interactive-widgets-and-layout-containers/下载了下面的脚本
我收到以下错误消息：name error:name'QApplication'未定义
我加了剧本的前两行。
那没用。
我想也许我不应该安装qt。但是当我试图运行PyQt4-4.10.3-gpl-Py2.7-Qt4.8.5-x32.exe时，程序告诉我它已经安装好了。
有人有什么建议吗？
马克
# copied from http://www.pythoncentral.io/pyside-pyqt-tutorial-interactive-widgets-and-layout-containers/
# Every Qt application must have one and only one QApplication object;
# it receives the command line arguments passed to the script, as they
# can be used to customize the application's appearance and behavior
import sys
from PyQt4 import QtGui, QtCore
#import PyQt4.QtGui, PyQt4.QtCore
qt_app = QApplication(sys.argv)
class AbsolutePositioningExample(QWidget):
''' An example of PySide absolute positioning; the main window
inherits from QWidget, a convenient widget for an empty window. '''
def __init__(self):
# Initialize the object as a QWidget
QWidget.__init__(self)
# We have to set the size of the main window
# ourselves, since we control the entire layout
self.setMinimumSize(400, 185)
self.setWindowTitle('Dynamic Greeter')
# Create the controls with this object as their parent and set
# their position individually; each row is a label followed by
# another control
# Label for the salutation chooser
self.salutation_lbl = QLabel('Salutation:', self)
self.salutation_lbl.move(5, 5) # offset the first control 5px
# from top and left
self.salutations = ['Ahoy',
'Good day',
'Hello',
'Heyo',
'Hi',
'Salutations',
'Wassup',
'Yo']
# Create and fill the combo box to choose the salutation
self.salutation = QComboBox(self)
self.salutation.addItems(self.salutations)
# Allow 100px for the label and 5px each for borders at the
# far left, between the label and the combobox, and at the far
# right
self.salutation.setMinimumWidth(285)
# Place it five pixels to the right of the end of the label
self.salutation.move(110, 5)
# The label for the recipient control
self.recipient_lbl = QLabel('Recipient:', self)
# 5 pixel indent, 25 pixels lower than last pair of widgets
self.recipient_lbl.move(5, 30)
# The recipient control is an entry textbox
self.recipient = QLineEdit(self)
# Add some ghost text to indicate what sort of thing to enter
self.recipient.setPlaceholderText(""e.g. 'world' or 'Matey'"")
# Same width as the salutation
self.recipient.setMinimumWidth(285)
# Same indent as salutation but 25 pixels lower
self.recipient.move(110, 30)
# The label for the greeting widget
self.greeting_lbl = QLabel('Greeting:', self)
# Same indent as the others, but 45 pixels lower so it has
# physical separation, indicating difference of function
self.greeting_lbl.move(5, 75)
# The greeting widget is also a label
self.greeting = QLabel('', self)
# Same indent as the other controls
self.greeting.move(110, 75)
# The build button is a push button
self.build_button = QPushButton('&Build Greeting', self)
# Place it at the bottom right, narrower than
# the other interactive widgets
self.build_button.setMinimumWidth(145)
self.build_button.move(250, 150)
def run(self):
# Show the form
self.show()
# Run the Qt application
qt_app.exec_()
# Create an instance of the application window and run it
app = AbsolutePositioningExample()
app.run()
最佳答案
如果您按顺序阅读本教程，您会看到系列中的the previous article在每个片段的开头显示了您需要分割的部分，以使其成为一个可运行的程序。作者这样做显然是为了让PyQt和PySide都能使用相同的代码。
因此，如果您使用的是PyQt4，则需要添加以下内容：
# Allow access to command-line arguments
import sys
# SIP allows us to select the API we wish to use
import sip
# use the more modern PyQt API (not enabled by default in Python 2.x);
# must precede importing any module that provides the API specified
sip.setapi('QDate', 2)
sip.setapi('QDateTime', 2)
sip.setapi('QString', 2)
sip.setapi('QTextStream', 2)
sip.setapi('QTime', 2)
sip.setapi('QUrl', 2)
sip.setapi('QVariant', 2)
# Import all of Qt
from PyQt4.Qt import *
如果PySide：
# Allow access to command-line arguments
import sys
# Import the core and GUI elements of Qt
from PySide.QtCore import *
from PySide.QtGui import *
在显示这个样板文件的框下面，有一个很好的、可读的解释，说明了它的含义以及为什么需要这样做。
不过，我建议你，如果你想从一个教程中学到东西，你应该从一开始就努力向前，而不是从中间开始，试图找出你一路上错过了什么。
如果您只是执行
from PyQt4 import QtGui, QtCore而不是从中导入*，则这些模块中的名称可用，但仅作为限定名。也就是说，您必须编写QApplication，而不是QtCore.QApplication。如果您不了解这一区别，请阅读正式的Python教程中的Modules或类似内容，了解导入的工作原理。
关于python - QApplication'未定义，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/20274856/