PyQt4 信号和槽用法总结

原文 http://neteue.com/article/pyqt4-signal-slot/

信号与槽的例子

可以使用QObject.connect方法来连接信号与槽

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

from PyQt4 import QtCore, QtGui

class MyWidget(QtGui.QWidget):
def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)

self.quit_button = QtGui.QPushButton("Quit", self)

layout = QtGui.QHBoxLayout()
layout.addWidget(self.quit_button)
self.setLayout(layout)
self.connect(self.quit_button, QtCore.SIGNAL("clicked()"),
QtGui.qApp, QtCore.SLOT("quit()"))

if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
win = MyWidget()
win.show()
sys.exit( app.exec_() )

在这个例子中, 使用了标准的连接方式connect(发送者, 信号, 接收者, 槽), Qt中的槽可以这样理解: 是接收者中经过包装后某个方法

自定义槽(slot)

当然可以通过QtCore.pyqtSlot自义一个槽, 在旧式风格中使用是的pyqtSignature, 建议使用pyqtSlot

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

from PyQt4 import QtCore, QtGui

class MyWidget(QtGui.QWidget):

def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)

self.ok_button = QtGui.QPushButton("OK", self)
layout = QtGui.QHBoxLayout()
layout.addWidget(self.ok_button)
self.setLayout(layout)

self.connect(self.ok_button, QtCore.SIGNAL('clicked()'),
self, QtCore.SLOT("on_ok_button_clicked()"))

@QtCore.pyqtSlot()
def on_ok_button_clicked(self):
print "OK"

if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
w = MyWidget()
w.show()
app.exec_()

发送信号

单击按钮后触发emit_python_list信号, 并且执行相应的槽

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

from PyQt4 import QtCore, QtGui

class MyWidget(QtGui.QWidget):

def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)

self.ok_button = QtGui.QPushButton("OK", self)

layout = QtGui.QHBoxLayout()
layout.addWidget(self.ok_button)
self.setLayout(layout)

self.connect(self.ok_button, QtCore.SIGNAL("clicked()"), self, QtCore.SLOT("slot1()"))
self.connect(self, QtCore.SIGNAL('emit_python_list(PyQt_PyObject)'),
self, QtCore.SLOT("slot2(PyQt_PyObject)"))

@QtCore.pyqtSlot()
def on_button_clicked(self):
print "click me!!!!"

@QtCore.pyqtSlot()
def slot1(self):
self.emit(QtCore.SIGNAL("emit_python_list(PyQt_PyObject)"), [1, 2, 3, 4, 5, 6])

@QtCore.pyqtSlot("PyQt_PyObject")
def slot2(self, alist):
print alist

if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
w = MyWidget()
w.show()
app.exec_()

执行Python方法

这里使用更加优雅直接的方式连接信号并执行回调, 这也是项目中用到最多的方式

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

from PyQt4 import QtCore, QtGui

class MyWidget(QtGui.QWidget):
def __init__(sel`f, parent=None):
super(MyWidget, self).__init__(parent)

self.ok_button = QtGui.QPushButton("ok", self)

layout = QtGui.QHBoxLayout()
layout.addWidget(self.ok_button)
self.setLayout(layout)

self.ok_button.clicked.connect(self.on_ok_button_clicked)

def on_ok_button_clicked(self):
print "OK"

if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
win = MyWidget()
win.show()
sys.exit( app.exec_() )

self.ok_button.clicked.connect 其中clicked是信号

注册信号

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

from PyQt4 import QtCore, QtGui

class MyWidget(QtGui.QWidget):

emit_python_list = QtCore.pyqtSignal(object)

def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)

self.ok_button = QtGui.QPushButton("OK", self)
layout = QtGui.QHBoxLayout()
layout.addWidget(self.ok_button)
self.setLayout(layout)

self.ok_button.clicked.connect(self.slot1)
self.emit_python_list.connect(self.slot2)

def slot1(self):
self.emit_python_list.emit([1, 2, 3, 4, 5, 6])

def slot2(self, alist):
print alist

if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
w = MyWidget()
w.show()
app.exec_()

自动连接

QMetaObject. connectSlotsByName(QObject)

其作用是如其名称一样，用来将QObject 里的子孙QObject的某些信号按照其objectName连接到相应的槽上,

如是使用pyuic生成的代码, 就是使用这种方式

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

from PyQt4 import QtCore, QtGui

class MyWidget(QtGui.QWidget):

def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)

self.ok_button = QtGui.QPushButton("OK", self)
self.ok_button.setObjectName("ok_button")

layout = QtGui.QHBoxLayout()
layout.addWidget(self.ok_button)
self.setLayout(layout)

QtCore.QMetaObject.connectSlotsByName(self)

@QtCore.pyqtSlot()         # 一定要有,不然会打印两遍 "OK"
def on_ok_button_clicked(self):
print "OK"

if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
w = MyWidget()
w.show()
app.exec_()

别忘了, 使用setObjectName设置对象名称