訊號與槽的例子

可以使用QObject.connect方法來連線訊號與槽

#! /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_() )

在這個例子中, 使用了標準的連線方式connect(傳送者, 訊號, 接收者, 槽), Qt中的槽可以這樣理解: 是接收者中經過包裝後某個方法

自定義槽(slot)

當然可以通過QtCore.pyqtSlot自義一個槽, 在舊式風格中使用是的pyqtSignature, 建議使用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_()

傳送訊號

單擊按鈕後觸發emit_python_list訊號, 並且執行相應的槽

#! /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_()

執行Python方法

這裡使用更加優雅直接的方式連線訊號並執行回撥, 這也是專案中用到最多的方式

#! /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是訊號

註冊訊號

#! /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_()

自動連線

QMetaObject. connectSlotsByName(QObject)

其作用是如其名稱一樣，用來將QObject 裡的子孫QObject的某些訊號按照其objectName連線到相應的槽上,

如是使用pyuic生成的程式碼, 就是使用這種方式

#! /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,不然會列印兩遍 "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_()

別忘了, 使用setObjectName設定物件名稱