PyQt4学习记录之事件和信号

事件是任何 GUI 程序中很重要的部分。所有 Python GUI 应用都是事件驱动的。一个应用对其生命期产生的不同的事件类型做出反应。事件是主要由应用的用户产生。但是，也可以通过其他方法产生，比如，网络通信，窗口的管理者，计时器。

PyQt 4.5 引入了新的 API 用于信号和槽。

这是旧式的 API 。

QtCore.QObject.connect(self.ui.button_open,QtCore.SIGNAL("clicked()"), self.file_dialog)

新式的更接近 Python 的标准

button.clicked.connect(self.onClicked)

self.ui对应窗口，通过它我们可以访问窗口中的部件。因此，self.ui.button_open对应“打开”按钮。self.file_dialog是信号对应的函数，它是比较重要的部分。

test.py测试代码：

import sys

from PyQt4 import QtCore, QtGui

from ui_test import Ui_notepad



class MyForm(QtGui.QMainWindow):def __init__(self, parent=None):

        QtGui.QWidget.__init__(self, parent)

        self.ui = Ui_notepad()

        self.ui.setupUi(self)

        # here we connect signals with our slots

        QtCore.QObject.connect(self.ui.button_open,QtCore.SIGNAL("clicked()"), self.file_dialog)

    def file_dialog(self):#self.ui.editor_window.setText('aaaaaaaaaa')

        fd = QtGui.QFileDialog(self)

        self.filename = fd.getOpenFileName()

        from os.path import isfile

        if isfile(self.filename):

            text = open(self.filename).read()

            self.ui.editor_window.setText(text)

        





if __name__ == "__main__":

    app = QtGui.QApplication(sys.argv)

    myapp = MyForm()

    myapp.show()

    sys.exit(app.exec_())

ui_test.py  UI生成代码：

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



# Form implementation generated from reading ui file 'test.ui'

#

# Created: Sat Jan 11 22:11:39 2014

# by: PyQt4 UI code generator 4.10.3

#

# 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)



class Ui_notepad(object):def setupUi(self, notepad):

        notepad.setObjectName(_fromUtf8("notepad"))

        notepad.resize(692, 462)

        self.button_open = QtGui.QPushButton(notepad)

        self.button_open.setGeometry(QtCore.QRect(60, 10, 75, 23))

        self.button_open.setObjectName(_fromUtf8("button_open"))

        self.button_close = QtGui.QPushButton(notepad)

        self.button_close.setGeometry(QtCore.QRect(290, 10, 75, 23))

        self.button_close.setObjectName(_fromUtf8("button_close"))

        self.editor_window = QtGui.QTextEdit(notepad)

        self.editor_window.setGeometry(QtCore.QRect(20, 50, 651, 381))

        self.editor_window.setObjectName(_fromUtf8("editor_window"))

        self.button_save = QtGui.QPushButton(notepad)

        self.button_save.setGeometry(QtCore.QRect(180, 10, 75, 23))

        self.button_save.setObjectName(_fromUtf8("button_save"))



        self.retranslateUi(notepad)

        QtCore.QObject.connect(self.button_close, QtCore.SIGNAL(_fromUtf8("clicked()")), notepad.close)

        QtCore.QMetaObject.connectSlotsByName(notepad)



    def retranslateUi(self, notepad):

        notepad.setWindowTitle(_translate("notepad", "Form", None))

        self.button_open.setText(_translate("notepad", "打开", None))

        self.button_close.setText(_translate("notepad", "关闭", None))

        self.button_save.setText(_translate("notepad", "保存", None))