PyQT：如何从外部函数访问MainWindow控件？

Question

比如，在主窗口里点击一个按钮，就会调用test()这个函数，往主窗口的文本编辑框里添加一些文字。

#!/usr/bin/python
# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'felch1.ui'
#
# Created: Fri Aug 15 15:19:31 2014
#      by: PyQt4 UI code generator 4.10.4
#
# WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    def _fromUtf8(s):
        return s

try:
    _encoding = QtGui.QApplication.UnicodeUTF8
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig)

def test():
    MainWindow.textEdit.append('button pushed')


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName(_fromUtf8("MainWindow"))
        MainWindow.resize(800, 600)
        self.centralwidget = QtGui.QWidget(MainWindow)
        self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
        self.pushButton = QtGui.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(30, 20, 131, 31))
        self.pushButton.setObjectName(_fromUtf8("pushButton"))
        self.textEdit = QtGui.QTextEdit(self.centralwidget)
        self.textEdit.setGeometry(QtCore.QRect(30, 80, 341, 441))
        self.textEdit.setObjectName(_fromUtf8("textEdit"))
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtGui.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 25))
        self.menubar.setObjectName(_fromUtf8("menubar"))
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtGui.QStatusBar(MainWindow)
        self.statusbar.setObjectName(_fromUtf8("statusbar"))
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QObject.connect(self.pushButton, QtCore.SIGNAL(_fromUtf8("clicked()")), test)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))
        self.pushButton.setText(_translate("MainWindow", "test", None))


if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    MainWindow = QtGui.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

我知道我不应该去修改自动生成的文件，只是在尝试弄明白如何从这个类外面的一个函数中引用主窗口的对象。

Answer 1

你可以把一个对象 QtGui.QMainWindow 传递给你想要的方法。可以通过使用 partial 来把你想要的参数传递给 test() 方法，这样就能把 MainWindow 对象传进去。

    from PyQt4 import QtCore, QtGui
    from functools import partial
        .
        .
        .
    def test(MainWindow):
        MainWindow.textEdit.append('button pushed')

    def setupUi(self, MainWindow):
        .
        .
        .
        MainWindow.textEdit = QtGui.QTextEdit(self.centralwidget) # Pass to QMainWindows not self
        MainWindow.textEdit.setGeometry(QtCore.QRect(30, 80, 341, 441))
        MainWindow.textEdit.setObjectName(_fromUtf8("textEdit"))
        MainWindow.setCentralWidget(self.centralwidget)
        .
        .
        .
        self.retranslateUi(MainWindow)
        QtCore.QObject.connect(MainWindow.pushButton, QtCore.SIGNAL(_fromUtf8("clicked()")), partial(test, MainWindow))
        QtCore.QMetaObject.connectSlotsByName(MainWindow)
        .
        .
        .

---

祝好，

Answer 2

我觉得最简单的方法是把 test 变成 Ui_MainWindow 的一个实例方法，同时把 MainWindow 对象保存为 Ui_MainWindow 的一个实例变量。

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName(_fromUtf8("MainWindow"))
        MainWindow.resize(800, 600)
        self.main_window = MainWindow

        # blah blah

        self.textEdit = QtGui.QTextEdit(self)
        self.pushButton = QtGui.QPushButton(self)
        self.pushButton.clicked.connect(self.test)

    def test(self):
        self.main_window.textEdit.append('button pushed')

如果你真的想让 test 成为一个顶层函数，你也可以使用 functools.partial，这样在执行 test 回调时就能把 MainWindow 对象传过去：

from functools import partial

def test(MainWindow):
    MainWindow.textEdit.append('button pushed')


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName(_fromUtf8("MainWindow"))
        MainWindow.resize(800, 600)

        # blah blah

        self.textEdit = QtGui.QTextEdit(self)
        self.pushButton = QtGui.QPushButton(self)
        test_func = partial(test, MainWindow)  # Calling test_func(arg) actually calls test(MainWindow, arg)
        self.pushButton.clicked.connect(test_func)