How can I know if the mouse is over the widget?

Question

I am fairly new to Qt (PyQt - PySide).
I am trying to build a custom widget which is a menu. However I have hit a hard road and I can not seem to be able to sort myself out. I've read the documentation but I don't think there is a mouse state I can verify to find out if mouse cursor is over the given widget.

I am calling a function upon the mouseReleaseEvent of a QWidget.

Ex.:

def mouseReleaseEvent(self, e):     

When this event is triggered, I have to know if the mouse is actually over the widget or outside of it (the widget of which this event is triggered).

    if mouseCursorOverSelf == True:
        # do something ..

How can I achieve this? What do I need to do?

Thank you very much!

Answer 1

If you want to keep track of when the mouse enters or leaves the widget you can use something like this:

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

from PyQt4 import QtCore, QtGui

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

    def enterEvent(self, event):
        print "Mouse Entered"
        return super(mainwindow, self).enterEvent(event)

    def leaveEvent(self, event):
        print "Mouse Left"
        return super(mainwindow, self).enterEvent(event)

if __name__ == "__main__":
    import sys

    app  = QtGui.QApplication(sys.argv)
    main = mainwindow()
    main.show()
    sys.exit(app.exec_())

If you just want to check whether the mouse is over the widget, you can use the QWidget::underMouse () function:

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

from PyQt4 import QtCore, QtGui

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

        self.button = QtGui.QPushButton("Check Mouse in 3 seconds")
        self.button.clicked.connect(self.on_button_clicked)

        self.layout = QtGui.QHBoxLayout(self)
        self.layout.addWidget(self.button)

    def mouseReleaseEvent(self, event):  
        if self.underMouse():
            print "Do something"

        return super(mainwindow, self).mouseReleaseEvent(event)

    @QtCore.pyqtSlot()
    def on_button_clicked(self):    
        QtCore.QTimer.singleShot(3000, self.checkMouse)

    def checkMouse(self):
        print "Under Mouse: {0}".format(self.underMouse())

if __name__ == "__main__":
    import sys

    app  = QtGui.QApplication(sys.argv)
    main = mainwindow()
    main.show()
    sys.exit(app.exec_())

Another method would involve checking if the position of the mouse is within the internal geometry of the widget:

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

from PyQt4 import QtCore, QtGui

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

        self.setMouseTracking(True)

    def mouseReleaseEvent(self, event):  
        posMouse =  event.pos()
        if self.rect().contains(posMouse):
            print "Under Mouse"

        return super(mainwindow, self).mouseReleaseEvent(event)

if __name__ == "__main__":
    import sys

    app  = QtGui.QApplication(sys.argv)
    main = mainwindow()
    main.show()
    main.resize(200, 200)
    sys.exit(app.exec_())