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我找不到将鼠标事件附加到场景的方法。没有查看所有事件都会被捕获，但是当被注释掉时，只有 mousePressEvent 有效。请帮忙。

from PySide import QtGui, QtCore

class Window(QtGui.QMainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)
        self.Scene()
        self.View()

    def mousePressEvent(self, event):
        if event.button() == QtCore.Qt.LeftButton:
            print "Pressed!!!"

    def mouseMoveEvent(self, event):
        print "moving....."

    def mouseReleaseEvent(self, event):
        print "-------released"

    def Scene(self):
        self.s = QtGui.QGraphicsScene(self)

    def View(self):
        self.v = QtGui.QGraphicsView(self.s)
        self.setCentralWidget(self.v)

if __name__ == '__main__':
    import sys
    app = QtGui.QApplication(sys.argv)
    window = Window()
    window.resize(300, 200)
    window.show()
    sys.exit(app.exec_())
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1 回答 1

4

在 Qt 中，事件是从子级到父级处理的。首先，孩子得到事件。然后它决定是否处理该事件。如果它不想对它采取行动，它可以ignore事件并且事件将被传递给父级。

在您的设置中，您有QMainWindow作为父级，aQGraphicsView作为它的子级。上的每个事件QGraphicsView都将由第一个处理QGraphicsView。如果它不想要这个事件，它会ignore它并传递给QMainWindow.

为了更好地可视化它，子类化QGraphicsView并覆盖它mouse*Event的 s：

from PySide import QtGui, QtCore

class View(QtGui.QGraphicsView):
    def mousePressEvent(self, event):
        print "QGraphicsView mousePress"

    def mouseMoveEvent(self, event):
        print "QGraphicsView mouseMove"

    def mouseReleaseEvent(self, event):
        print "QGraphicsView mouseRelease"

class Window(QtGui.QMainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)
        self.Scene()
        self.View()

    def mousePressEvent(self, event):
        print "QMainWindow mousePress"

    def mouseMoveEvent(self, event):
        print "QMainWindow mouseMove"

    def mouseReleaseEvent(self, event):
        print "QMainWindow mouseRelease"

    def Scene(self):
        self.s = QtGui.QGraphicsScene(self)

    def View(self):
        self.v = View(self.s)
        self.setCentralWidget(self.v)

if __name__ == '__main__':
    import sys
    app = QtGui.QApplication(sys.argv)
    window = Window()
    window.resize(300, 200)
    window.show()
    sys.exit(app.exec_())

您会看到如下输出：

QGraphicsView mousePress
QGraphicsView mouseMove
...
QGraphicsView mouseMove
QGraphicsView mouseRelease

如您所见，只有view“看到”事件，因为view不选择传递事件。

或者，您可以选择忽略QGraphicsView. 这就像在说‘我什么都不做，让别人来处理它’。并且该事件将被传递给父级以选择要执行的操作：

class View(QtGui.QGraphicsView):
    def mousePressEvent(self, event):
        print "QGraphicsView mousePress"
        # ignore the event to pass on the parent.
        event.ignore()

    def mouseMoveEvent(self, event):
        print "QGraphicsView mouseMove"
        event.ignore()

    def mouseReleaseEvent(self, event):
        print "QGraphicsView mouseRelease"
        event.ignore()

和输出：

QGraphicsView mousePress
QMainWindow mousePress
QGraphicsView mouseMove
QMainWindow mouseMove
...
QGraphicsView mouseMove
QMainWindow mouseMove
QGraphicsView mouseRelease
QMainWindow mouseRelease

现在，您可以看到它view首先获取事件。但由于它ignore是事件，它被传递到主窗口，然后才QMainWindow接收信号。

长话短说，别着急。您view将收到事件并对其采取行动。

于 2013-02-05T09:31:56.427 回答