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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) # 避免窗口大小重绘事件的影响,可以把参数0改变成3000(3秒),然后在运行,就可以明白这行代码的意思。
def giveHelp(self):
self.text = "请点击这里触发追踪鼠标功能"
self.update() # 重绘事件,也就是触发paintEvent函数。
'''重新实现关闭事件'''
def closeEvent(self, event):
print("Closed")
'''重新实现上下文菜单事件'''
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())
'''上下文菜单槽函数'''
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()
'''重新实现绘制事件'''
def paintEvent(self, event):
text = self.text
i = text.find("\n\n")
if i >= 0:
text = text[0:i]
if self.key: # 若触发了键盘按钮,则在文本信息中记录这个按钮信息。
text += "\n\n你按下了: {0}".format(self.key)
painter = QPainter(self)
painter.setRenderHint(QPainter.TextAntialiasing)
painter.drawText(self.rect(), Qt.AlignCenter, text) # 绘制信息文本的内容
if self.message: # 若消息文本存在则在底部居中绘制消息,5秒钟后清空消息文本并重绘。
painter.drawText(self.rect(), Qt.AlignBottom | Qt.AlignHCenter,
self.message)
QTimer.singleShot(5000, self.clearMessage)
QTimer.singleShot(5000, self.update)
'''清空消息文本的槽函数'''
def clearMessage(self):
self.message = ""
'''重新实现调整窗口大小事件'''
def resizeEvent(self, event):
self.text = "调整窗口大小为: QSize({0}, {1})".format(
event.size().width(), event.size().height())
self.update()
'''重新实现鼠标释放事件'''
def mouseReleaseEvent(self, event):
# 若鼠标释放为双击释放,则不跟踪鼠标移动
# 若鼠标释放为单击释放,则需要改变跟踪功能的状态,如果开启跟踪功能的话就跟踪,不开启跟踪功能就不跟踪
if self.justDoubleClicked:
self.justDoubleClicked = False
else:
self.setMouseTracking(not self.hasMouseTracking()) # 单击鼠标
if self.hasMouseTracking():
self.text = "开启鼠标跟踪功能.\n" + \
"请移动一下鼠标!\n" + \
"单击鼠标可以关闭这个功能"
else:
self.text = "关闭鼠标跟踪功能.\n" + \
"单击鼠标可以开启这个功能"
self.update()
'''重新实现鼠标移动事件'''
def mouseMoveEvent(self, event):
if not self.justDoubleClicked:
globalPos = self.mapToGlobal(event.pos()) # 窗口坐标转换为屏幕坐标
self.text = """鼠标位置:
窗口坐标为:QPoint({0}, {1})
屏幕坐标为:QPoint({2}, {3}) """.format(event.pos().x(), event.pos().y(), globalPos.x(), globalPos.y())
self.update()
'''重新实现鼠标双击事件'''
def mouseDoubleClickEvent(self, event):
self.justDoubleClicked = True
self.text = "你双击了鼠标"
self.update()
'''重新实现键盘按下事件'''
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)
'''重新实现其他事件,适用于PyQt没有提供该事件的处理函数的情况,Tab键由于涉及焦点切换,不会传递给keyPressEvent,因此,需要在这里重新定义。'''
def event(self, event):
if (event.type() == QEvent.KeyPress and
event.key() == Qt.Key_Tab):
self.key = "在event()中捕获Tab键"
self.update()
return True
return QWidget.event(self, event)
if name == "main": app = QApplication(sys.argv) form = Widget() form.show() app.exec_()