我对 Python 和 Qt 还很陌生，但我正在尝试创建一个带有一些动画图形元素的 GUI。我可以制作简单的动画作品；下面的代码class MyView在调用时会起作用，但class GraphicsView不是动画！
谁能帮我看看问题？
问题出在GraphicsScene类中，我认为：
import sys
from PyQt4 import QtGui, QtCore
class MyView(QtGui.QGraphicsView):
def __init__(self):
QtGui.QGraphicsView.__init__(self)
self.scene = QtGui.QGraphicsScene(self)
self.item = QtGui.QGraphicsEllipseItem(-20, -10, 40, 20)
self.scene.addItem(self.item)
self.setScene(self.scene)
# Remember to hold the references to QTimeLine and QGraphicsItemAnimation instances.
# They are not kept anywhere, even if you invoke QTimeLine.start().
self.tl = QtCore.QTimeLine(1000)
self.tl.setFrameRange(0, 100)
self.a = QtGui.QGraphicsItemAnimation()
self.a.setItem(self.item)
self.a.setTimeLine(self.tl)
# Each method determining an animation state (e.g. setPosAt, setRotationAt etc.)
# takes as a first argument a step which is a value between 0 (the beginning of the
# animation) and 1 (the end of the animation)
self.a.setPosAt(0, QtCore.QPointF(0, -10))
self.a.setRotationAt(1, 360)
self.tl.start()
#create the graphicsView which contains the graphicsScene
class GraphicsView(QtGui.QGraphicsView):
#initialize and set dragMode and renderHints for everything inside the view
def __init__(self, parent=None):
super(GraphicsView, self).__init__(parent)
#the dragMode should be changed to use the rihgt-mousebutton
self.setDragMode(QtGui.QGraphicsView.ScrollHandDrag)
self.setRenderHint(QtGui.QPainter.Antialiasing)
self.setRenderHint(QtGui.QPainter.TextAntialiasing)
#crate a zoom function for the mouse-wheel
def wheelEvent(self, event):
factor = 1.5 ** (event.delta() / 240.0)
self.scale(factor, factor)
#create the GraphicsScene containing the main graphics
class GraphicsScene(QtGui.QGraphicsScene):
def animate(self):
self.animations = range(3)
#move item to position(x,y) at time t
def animate_to(item,x,y,t):
animation = QtGui.QGraphicsItemAnimation()
#create a timeline of 1 second
timeline = QtCore.QTimeLine(2000)
#number of steps in timeline (100)
timeline.setFrameRange(0,100)
#set position at time t
animation.setPosAt(t, QtCore.QPointF(x,y))
#apply this to "item"
animation.setItem(item)
#add timeline to the animation
animation.setTimeLine(timeline)
#output of this definition is "animation"
return animation
self.animations[0] = animate_to(self.geos[0],200,200,0.2)
self.animations[1] = animate_to(self.geos[1],200,200,0.2)
self.animations[2] = animate_to(self.geos[2],200,200,0.2)
#animation.timeline().start()
self.animator.start(2000)
def __init__(self, parent=None):
QtGui.QGraphicsScene.__init__(self, parent)
#set the size of the scene
self.setSceneRect(0,0,2000,2000)
#self.addRect(QtCore.QRectF(800,800,200,200))
#---create the scene-geometries ---
#empty list to hold the geometries
self.geos = []
#create stuff to add to the scene
geo_01 = QtGui.QGraphicsEllipseItem(800,800,200,200)
geo_02 = QtGui.QGraphicsEllipseItem(850,850,300,300)
geo_03 = QtGui.QGraphicsEllipseItem(900,900,400,400)
#add stuff to the scene
self.addItem(geo_01)
self.addItem(geo_02)
self.addItem(geo_03)
#put stuff into list so it can be referenced
self.geos.append(geo_01)
self.geos.append(geo_02)
self.geos.append(geo_03)
#----do the animation thing---
self.animator = QtCore.QTimer()
self.animator.timeout.connect(self.animate)
self.animate()
#Create a new class which inherrits from "QtGui.QMainWindow"
class Example(QtGui.QMainWindow):
def __init__(self):
#The "super()"-method returns the parrent object of the example-class
#and it's constructor is called ("__init__")
super(Example, self).__init__()
self.initUI()
#create the GUI
def initUI(self):
"""---create the buttons---"""
#set a font for the tool-tips
QtGui.QToolTip.setFont(QtGui.QFont('SansSerif', 10))
#create a button and a tool-tip for the button
btn_01 = QtGui.QPushButton('Button', self)
btn_01.setToolTip('This is a <b>QPushButton</b> widget')
#resize the button with a recommended size (.sizeHint())
btn_01.resize(btn_01.sizeHint())
#create a button and a tool-tip for the button
btn_02 = QtGui.QPushButton('Button', self)
btn_02.setToolTip('This is a <b>QPushButton</b> widget')
#resize the button with a recommended size (.sizeHint())
btn_02.resize(btn_02.sizeHint())
"""----create a layout----"""
#create the main widget, which holds the layout
self.main_widget = QtGui.QWidget(self)
#create a vertical box layout to hold the buttons on the right
vbox = QtGui.QVBoxLayout()
vbox.addStretch(1)
vbox.addWidget(btn_01)
vbox.addWidget(btn_02)
#create horizontal box layout to hold the vbox and the main area
hbox = QtGui.QHBoxLayout()
#store the GraphicsScene in a variable so it is not destroyed
self.scene = GraphicsScene()
#add the scene to the GraphicsView
view = GraphicsView(self.scene)
hbox.addWidget(view)
hbox.addStretch(1)
hbox.addLayout(vbox)
self.main_widget.setLayout(hbox)
self.setCentralWidget(self.main_widget)
#set the possition and size of the window, then set the window title
#these methods have been inherited by the "QtGui.QWidget"-class
self.setGeometry(100, 100, 700, 500)
self.setWindowTitle("PatternNexus...Maybe?")
#self.setWindowIcon(QtGui.QIcon('web.png'))
self.show()
def closeEvent(self, event):
#create a messagebox to confirm quit
# when QtGui.QWidget is closed the QtGui.QCloseEvent is generated
# to modify its behaviour the event handler (closeEvent()) must be reinplemented
#create a msgBox with 2 buttons
#4th argument is the button combination
#5th argument is the button with initial ketboard focus
reply = QtGui.QMessageBox.question(self, 'Message',
"Are you leaving?", QtGui.QMessageBox.Yes |
QtGui.QMessageBox.No, QtGui.QMessageBox.No)
#test the return value, is "yes" the event is accepted
if reply == QtGui.QMessageBox.Yes:
event.accept()
else:
event.ignore()
def main():
#start the application
app = QtGui.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
#if this module (.py-file) is run as the main program the statement is true
#if this module is imported the statement will return false
if __name__ == '__main__':
main()
我对此进行编码的主要参考资料是“使用 python 和 QT 进行快速 GUI 编程 - 第 12 章”，这些链接：http ://lateral.netmanagers.com.ar/stories/BBS53.html和http://www.diotavelli .net/PyQtWiki/GraphicsView_-_SimpleAnimation