Question

我尝试在PyQt5和Python3.5中使用mouseMoveEvent和mousePressEvent，但是当我点击鼠标时没有任何内容。我的代码如下，有什么不对吗？

from PyQt5 import QtWidgets, QtGui, QtCore

class Window(QtWidgets.QMainWindow):
    def __init__(self):
        QtWidgets.QMainWindow.__init__(self)
        widget = QtWidgets.QWidget(self)
        layout = QtWidgets.QVBoxLayout(widget)
        self.graphicsView = QtWidgets.QGraphicsView()
        self.graphicsView.setCursor(QtCore.Qt.CrossCursor)
        self.graphicsView.setObjectName("graphicsView")
        layout.addWidget(self.graphicsView)
        self.setCentralWidget(widget)

    def mouseMoveEvent(self, event):
        if event.buttons() == QtCore.Qt.NoButton:
            print("Simple mouse motion")
        elif event.buttons() == QtCore.Qt.LeftButton:
            print("Left click drag")
        elif event.buttons() == QtCore.Qt.RightButton:
            print("Right click drag")

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

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    win = Window()
    win.show()
    sys.exit(app.exec_())

Answer 1

首先，您必须启用mouse-tracking：

        self.graphicsView.setMouseTracking(True)

然后你可以使用QGraphicsView的子类：

class GraphicsView(QtWidgets.QGraphicsView):   
    def mouseMoveEvent(self, event):
        if event.buttons() == QtCore.Qt.NoButton:
            print("Simple mouse motion")
        elif event.buttons() == QtCore.Qt.LeftButton:
            print("Left click drag")
        elif event.buttons() == QtCore.Qt.RightButton:
            print("Right click drag")
        super(GraphicsView, self).mouseMoveEvent(event)

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

或安装事件过滤器：

        self.graphicsView.viewport().installEventFilter(self)
        ...

    def eventFilter(self, source, event):
        if event.type() == QtCore.QEvent.MouseMove:
            if event.buttons() == QtCore.Qt.NoButton:
                print("Simple mouse motion")
            elif event.buttons() == QtCore.Qt.LeftButton:
                print("Left click drag")
            elif event.buttons() == QtCore.Qt.RightButton:
                print("Right click drag")
        elif event.type() == QtCore.QEvent.MouseButtonPress:
            if event.button() == QtCore.Qt.LeftButton:
                print("Press!")
        return super(Window, self).eventFilter(source, event)

Answer 2

我确信您的活动是在QGraphicsView内处理的。您必须阅读有关事件传播的更多信息。尝试不在Window上添加任何其他小部件。并且不要忘记abt MouseTracking属性，默认情况下为false，没有按钮的鼠标移动事件根本不会发生。

我建议您阅读this文章。它已经很老了，但仍然相关。此外，QGraphicsView中的鼠标事件以不同的方式处理，请阅读docs以获取更多详细信息。

Sory没有代码样本，因为我是C ++开发人员。

为什么mouseMoveEvent在PyQt5中什么都不做

2 个答案: