PyQt4 訊號和槽用法總結
阿新 • • 發佈:2019-01-07
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