本文是对《python qt gui快速编程》的第10章的例子events用python3+pyqt5进行改写，涉及到重新实现qwidget的事件处理程序。本例子涉及到上下文菜单，鼠标事件，键盘事件，可作为重新实现事件处理程序的参考。
注：在创建上下文菜单最简单的方式使用qwidget.addaction()把动作添加到窗口部件中，再把窗口部件的上下文菜单策略设置为qt.actionscontextmenu即可，但是如果像本例子一样要根据不同的状态来提供不同的选项，则要重新实现上下文菜单事件处理程序。
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#!/usr/bin/env python3import sysfrom pyqt5.qtcore import (qevent, qtimer, qt)from pyqt5.qtwidgets import (qapplication, qmenu, qwidget)from pyqt5.qtgui import qpainterclass widget(qwidget): def __init__(self, parent=none): super(widget, self).__init__(parent) self.justdoubleclicked = false self.key = "" self.text = "" self.message = "" self.resize(400, 300) self.move(100, 100) self.setwindowtitle("events") qtimer.singleshot(0, self.givehelp) # avoids first resize msg def givehelp(self): self.text = "click to toggle mouse tracking" self.update() def closeevent(self, event): print("closed") def contextmenuevent(self, event): menu = qmenu(self) oneaction = menu.addaction("&one") twoaction = menu.addaction("&two") oneaction.triggered.connect(self.one) twoaction.triggered.connect(self.two) if not self.message: menu.addseparator() threeaction = menu.addaction("thre&e") threeaction.triggered.connect(self.three) menu.exec_(event.globalpos()) def one(self): self.message = "menu option one" self.update() def two(self): self.message = "menu option two" self.update() def three(self): self.message = "menu option three" self.update() def paintevent(self, event): text = self.text i = text.find("\n\n") if i >= 0: text = text[0:i] if self.key: text += "\n\nyou pressed: {0}".format(self.key) painter = qpainter(self) painter.setrenderhint(qpainter.textantialiasing) painter.drawtext(self.rect(), qt.aligncenter, text) if self.message: painter.drawtext(self.rect(), qt.alignbottom|qt.alignhcenter, self.message) qtimer.singleshot(5000, self.clearmessage) qtimer.singleshot(5000, self.update) def clearmessage(self): self.message="" def resizeevent(self, event): self.text = "resized to qsize({0}, {1})".format( event.size().width(), event.size().height()) self.update() def mousereleaseevent(self, event): if self.justdoubleclicked: self.justdoubleclicked = false else: self.setmousetracking(not self.hasmousetracking()) if self.hasmousetracking(): self.text = "mouse tracking is on.\n"+\ "try moving the mouse!\n"+\ "single click to switch it off" else: self.text = "mouse tracking is off.\n"+\ "single click to switch it on" self.update() def mousemoveevent(self, event): if not self.justdoubleclicked: globalpos = self.maptoglobal(event.pos()) self.text = "the mouse is at\nqpoint({0}, {1}) "+\ "in widget coords, and\n"+\ "qpoint({2}, {3}) in screen coords".format( event.pos().x(), event.pos().y(), globalpos.x(), globalpos.y()) self.update() def mousedoubleclickevent(self, event): self.justdoubleclicked = true self.text = "double-clicked." self.update() def keypressevent(self, event): self.key = "" if event.key() == qt.key_home: self.key = "home" elif event.key() == qt.key_end: self.key = "end" elif event.key() == qt.key_pageup: if event.modifiers() & qt.controlmodifier: self.key = "ctrl+pageup" else: self.key = "pageup" elif event.key() == qt.key_pagedown: if event.modifiers() & qt.controlmodifier: self.key = "ctrl+pagedown" else: self.key = "pagedown" elif qt.key_a <= event.key() <= qt.key_z: if event.modifiers() & qt.shiftmodifier: self.key = "shift+" self.key += event.text() if self.key: self.key = self.key self.update() else: qwidget.keypressevent(self, event) def event(self, event): if (event.type() == qevent.keypress and event.key() == qt.key_tab): self.key = "tab captured in event()" self.update() return true return qwidget.event(self, event)if __name__ == "__main__": app = qapplication(sys.argv) form = widget() form.show() app.exec_() |
运行结果：
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原文链接：https://blog.csdn.net/xiaoyangyang20/article/details/54706445
