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Pyqt4鼠标释放事件不起作用

pyqt4 pyqt python

user1050619 · 技术社区 · 7 年前

我试图跟踪一个鼠标按下和鼠标释放事件,但它无法识别鼠标释放事件。

import sys, os

from PyQt4.QtCore import *
from PyQt4.QtGui import *



class Widget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)

        self.btn = QPushButton("Add Line")

        self.gv = QGraphicsView()
        self.scene = QGraphicsScene(self)
        self.gv.setScene(self.scene)
        self.gv.setRenderHints(QPainter.Antialiasing | QPainter.SmoothPixmapTransform)

        lay = QHBoxLayout(self)
        lay.addWidget(self.btn)
        lay.addWidget(self.gv)
        script_dir = sys.path[0]

        image_loc = os.path.dirname(script_dir) + '/testproject/configs/files/lena.png'
        print image_loc
        #self.p_item = self.scene.addPixmap(QPixmap("lena.png"))
        self.p_item = self.scene.addPixmap(QPixmap(image_loc))

        self.btn.clicked.connect(self.add_line)

    def add_line(self, event):
        import pprint
        print pprint.pprint(dir(event))
        pass

    def mousePressEvent(self, QMouseEvent):
        print 'mouse press event = ', QMouseEvent.pos()

    def mouseReleaseEvent(self, QMouseEvent):
        print 'mouse release event = ', QMouseEvent.pos()
        # cursor = QCursor()
        # print 'mouse release event = ', cursor.pos()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())

1 回复 | 直到 7 年前

eyllanesc 7 年前

在qt中,事件从父代传递给子代,而不是从父代传递给子代。在你的情况下 mousePressEvent 在小部件中启动,然后可以移动到 QPushButton 或 QGraphicsView ,假设在这种情况下 Q图形视图 然后它发生在您的子窗口小部件上,称为 viewport() ,此操作将在某个小部件接受事件之前完成,同样的情况也必须发生在 mouseReleaseEvent ,但对于要接收 释放事件 一定是接受了 鼠标压力 事件,唯一这样做的是 VIEW() 属于 Q图形视图 . 解决方案是在 VIEW() 属于 Q图形视图 如下所示。

class Widget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)    
        self.btn = QPushButton("Add Line")

        self.gv = QGraphicsView()
        self.scene = QGraphicsScene(self)
        self.gv.setScene(self.scene)
        self.gv.setRenderHints(QPainter.Antialiasing | QPainter.SmoothPixmapTransform)

        lay = QHBoxLayout(self)
        lay.addWidget(self.btn)
        lay.addWidget(self.gv)
        script_dir = sys.path[0]

        image_loc = os.path.dirname(script_dir) + '/testproject/configs/files/lena.png'
        print(image_loc)
        #self.p_item = self.scene.addPixmap(QPixmap("lena.png"))
        self.p_item = self.scene.addPixmap(QPixmap(image_loc))

        self.btn.clicked.connect(self.add_line)

        self.gv.viewport().installEventFilter(self) # <----

    def add_line(self, event):
        import pprint
        print(pprint.pprint(dir(event)))

    def eventFilter(self, obj, event):
        if obj is self.gv.viewport():
            if event.type() == QEvent.MouseButtonPress:
                print('mouse press event = ', event.pos())
            elif event.type() == QEvent.MouseButtonRelease:
                print('mouse release event = ', event.pos())

        return QWidget.eventFilter(self, obj, event)