Python类之间的信号与槽

Question

我正在尝试用Python/PyQt制作一个图形界面应用程序，想要创建一个滑块对话框类，通过信号把一组缩放值发送到主窗口。但是，下面的代码没有成功。滑块的值确实在变化……但是主窗口并没有接收到信号，我原以为发出信号就能通知主窗口。结果并不是这样。有人能帮忙吗？哦，我知道我还没有设置好传递缩放值的部分，但由于信号没有工作，所以我也没继续这个部分。

from PyQt4 import QtCore
from PyQt4 import QtGui

OFFSET_Y = 15
OFFSET_X = 5
SPACER_Y = 20
SPACER_X = 50
switch = [1.0, 2.0, 3.0, 6.0, 9.0, 12.0, 18.0]

class MainWindow(QtGui.QMainWindow):

    sliderUpdate = QtCore.SIGNAL('sliderUpdate()')

    def __init__(self):
        super(MainWindow, self).__init__()
        sdlg = SliderDialog(self, 5)
        sdlg.connect(self, QtCore.SIGNAL('sliderUpdate'), self.scalers)
        sdlg.show()

    def scalers(self) :
        print "In scalers of MainWindow!"

class SliderDialog(QtGui.QDialog) :

    sliderMoved  = QtCore.pyqtSignal()

    def __init__( self, parent, dataCount ) :
        super(SliderDialog, self).__init__(parent)

        sliderLayout = QtGui.QVBoxLayout()
        sliderLayout.addStretch()

        self.slider = []
        self.sliderLabel = []
        for i in range(dataCount) :

            s = QtGui.QSlider(QtCore.Qt.Horizontal, self)
            s.setMinimum(0)
            s.setMaximum(len(switch)-1)
            s.setTickInterval(1)
            s.setSingleStep(1)
            s.move(170, OFFSET_Y+30 + 3*SPACER_Y*i)
            s.sliderReleased.connect(self.sliderMoved)

            sl = QtGui.QLabel("Scaling to : 1.0", self)
            sl.move(5, OFFSET_Y+30 + 3*SPACER_Y*i)

            self.slider.append(s)
            self.sliderLabel.append(sl)

            sliderLayout.addWidget(self.slider[i])
            sliderLayout.addWidget(self.sliderLabel[i])

    def sliderMoved(self) :
        for i, slides in enumerate(self.slider) :
            scaler = slides.sliderPosition()
            self.sliderLabel[i].setText("Scaling to: {}".format(switch[scaler]))
            self.emit(QtCore.SIGNAL('sliderUpdate'))

if __name__ == '__main__':

    import sys

    app = QtGui.QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

Answer 1

问题在于你使用的'connect'参数不正确；

bool QObject.connect (QObject, SIGNAL(), callable, Qt.ConnectionType = Qt.AutoConnection)

参数：

1. QObject  : Source object to receive emit signal

2. SIGNAL() : Signal name

3. callable : Callable do your want go it then have signal from source object

4. (Optional)

要解决这个问题，请把正确的参数放在正确的位置。

从；

sdlg.connect(self, QtCore.SIGNAL('sliderUpdate'), self.scalers)

到；

self.connect(sdlg, QtCore.SIGNAL('sliderUpdate'), self.scalers)

---

参考链接 : http://pyqt.sourceforge.net/Docs/PyQt4/qobject.html#connect-2

---

最后编辑于 2014年8月18日 11:37 : 添加完整代码；

from PyQt4 import QtCore
from PyQt4 import QtGui

OFFSET_Y = 15
OFFSET_X = 5
SPACER_Y = 20
SPACER_X = 50
switch = [1.0, 2.0, 3.0, 6.0, 9.0, 12.0, 18.0]

class MainWindow(QtGui.QMainWindow):

    sliderUpdate = QtCore.SIGNAL('sliderUpdate()')

    def __init__(self):
        super(MainWindow, self).__init__()
        sdlg = SliderDialog(self, 5)
        self.connect(sdlg, QtCore.SIGNAL('sliderUpdate'), self.scalers)
        sdlg.show()

    def scalers(self) :
        print "In scalers of MainWindow!"

class SliderDialog(QtGui.QDialog) :

    sliderMoved  = QtCore.pyqtSignal()

    def __init__( self, parent, dataCount ) :
        super(SliderDialog, self).__init__(parent)

        sliderLayout = QtGui.QVBoxLayout()
        sliderLayout.addStretch()

        self.slider = []
        self.sliderLabel = []
        for i in range(dataCount) :

            s = QtGui.QSlider(QtCore.Qt.Horizontal, self)
            s.setMinimum(0)
            s.setMaximum(len(switch)-1)
            s.setTickInterval(1)
            s.setSingleStep(1)
            s.move(170, OFFSET_Y+30 + 3*SPACER_Y*i)
            s.sliderReleased.connect(self.sliderMoved)

            sl = QtGui.QLabel("Scaling to : 1.0", self)
            sl.move(5, OFFSET_Y+30 + 3*SPACER_Y*i)

            self.slider.append(s)
            self.sliderLabel.append(sl)

            sliderLayout.addWidget(self.slider[i])
            sliderLayout.addWidget(self.sliderLabel[i])

    def sliderMoved(self) :
        for i, slides in enumerate(self.slider) :
            scaler = slides.sliderPosition()
            self.sliderLabel[i].setText("Scaling to: {}".format(switch[scaler]))
            self.emit(QtCore.SIGNAL('sliderUpdate'))

if __name__ == '__main__':

    import sys

    app = QtGui.QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

---

祝好，