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 python3
import sys
from pyqt5.qtcore import (qevent, qtimer, qt)
from pyqt5.qtwidgets import (qapplication, qmenu, qwidget)
from pyqt5.qtgui import qpainter
class 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_()
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运行结果：
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/xiaoyangyang20/article/details/54706445