Python PyQt QPainter部件在布局中不显示

#!/usr/bin/python3 import sys from PyQt4 import QtCore, QtGui class DrawCircle(QtGui.QWidget): def __init__(self, color, parent=None): QtGui.QWidget.__init__(self, parent) self.color = color def setColor(self,color): self.color = color def paintEvent(self,event): self.paint = QtGui.QPainter() self.paint.begin(self) self.paint.setRenderHint(QtGui.QPainter.Antialiasing) radx = 30 rady = radx if self.color == 'red': self.paint.setPen(QtCore.Qt.red) self.paint.setBrush(QtCore.Qt.red) elif self.color == 'green': self.paint.setPen(QtCore.Qt.green) self.paint.setBrush(QtCore.Qt.green) k = int(radx * 1.5) center = QtCore.QPoint(k,k) self.paint.drawEllipse(center,radx,rady) self.paint.end() class Window(QtGui.QMainWindow, QtGui.QGraphicsView): def __init__(self): super(Window,self).__init__() # GUI Setup self.myWid = QtGui.QWidget() # Establish a Vertical Box Layout # The layout will be a vertical box layout comprised of horizontal # box layouts self.vbox_fullDisplay = QtGui.QVBoxLayout() # Add a Zero-width spacer-item before the area where the # text label will appear self.vbox_fullDisplay.addStretch(1) ############################### # Build horizontal box layout # ############################### self.hbox_top = QtGui.QHBoxLayout() # The text should be centered on the screen so zero-width # spacer items will be added to the left and right of the label self.hbox_top.addStretch(1) self.top_text_label = QtGui.QLabel(self) self.top_text_label.setFont(QtGui.QFont("Times",32,QtGui.QFont.Bold)) self.top_text_label.setText("Top of window") self.top_text_label.adjustSize() self.hbox_top.addWidget(self.top_text_label) self.hbox_top.addStretch(1) # Add the horizontal box layout to the vertical box layout self.vbox_fullDisplay.addLayout(self.hbox_top) # Add space between the text and the row of circles self.vbox_fullDisplay.addStretch(1) ############################ # Build the row of buttons # ############################ self.hbox_buttons = QtGui.QHBoxLayout() # The text should be centered on the screen so zero-width # spacer items will be added to the left and right of the label self.hbox_buttons.addStretch(1) # These buttons will be used to toggle the color of the circles btn1 = QtGui.QPushButton('Circle 1') btn1.clicked.connect(self.circle1Meth) btn2 = QtGui.QPushButton('Circle 2') btn2.clicked.connect(self.circle2Meth) self.hbox_buttons.addWidget(btn1) self.hbox_buttons.addStretch(1) self.hbox_buttons.addWidget(btn2) self.hbox_buttons.addStretch(1) # Add the horizontal box layout to the vertical box layout self.vbox_fullDisplay.addLayout(self.hbox_buttons) # Add space between the text and the row of circles self.vbox_fullDisplay.addStretch(1) ############################ # Build the row of circles # ############################ self.hbox_circles = QtGui.QHBoxLayout() self.hbox_circles.addStretch(1) self.__circleColors = ['red','green'] self.__circle1Color = 0; self.circle1 = DrawCircle(self.__circleColors[self.__circle1Color]) print("const draw circ2") self.__circle2Color = 1 self.circle2 = DrawCircle(self.__circleColors[self.__circle2Color]) self.hbox_circles.addWidget(self.circle1) self.hbox_circles.addStretch(1) self.hbox_circles.addWidget(self.circle2) self.hbox_circles.addStretch(1) # Add the row of circles to the vertical box layout self.vbox_fullDisplay.addLayout(self.hbox_circles) # Add space between the circles and the slot machine pictures self.vbox_fullDisplay.addStretch(1) self.bottomLabel = QtGui.QLabel(self) self.bottomLabel.setText("Bottom Of GUI") self.bottomLabel.adjustSize() self.vbox_fullDisplay.addWidget(self.bottomLabel) self.myWid.setLayout(self.vbox_fullDisplay) self.setCentralWidget(self.myWid) self.setGeometry(100,200,600,500) self.setWindowTitle('Does this work') def circle1Meth(self): print("Circ1 change") if self.__circle1Color == 1: self.__circle1Color = 0 else: self.__circle1Color = 1 # Set the color for circle 1 self.circle1.setColor(self.__circleColors[self.__circle1Color]) # force a repaint by updating the widget Using the repaint() method # could cause infinite recursion self.update() def circle2Meth(self): print("Circ2 change") if self.__circle2Color == 1: self.__circle2Color = 0 else: self.__circle2Color = 1 # Set the color for circle 1 self.circle2.setColor(self.__circleColors[self.__circle2Color]) # force a repaint by updating the widget Using the repaint() method # could cause infinite recursion self.update() ### # Run GUI ### app = QtGui.QApplication(sys.argv) win = Window() win.show() sys.exit(app.exec_())

1条回答

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1楼 · 发布于 2024-09-30 04:41:06

当您使用addStrech()时，布局将使用sizeHint()作为大小，因为没有设置大小，因此它不可见，解决方案是设置该属性。另一个建议是不要使QPainter成为类的成员，因为它以不可避免的方式消耗内存，只需使其成为局部变量。另一个建议是在setColor()方法中调用update()，它不会为您节省代码行，而且您的代码更简洁。在

class DrawCircle(QtGui.QWidget):
    def __init__(self, color, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.color = color

    def setColor(self,color):
        self.color = color
        self.update()

    def paintEvent(self,event):
        painter = QtGui.QPainter(self)
        painter.setRenderHint(QtGui.QPainter.Antialiasing)
        radx = 5
        rady = radx
        if self.color in ('red', 'green'):
            col = QtGui.QColor(self.color)
            painter.setPen(col)
            painter.setBrush(col)
        k = int(radx * 1.5)
        center = QtCore.QPoint(k,k)
        painter.drawEllipse(center,radx,rady)

    def sizeHint(self):
        return QtCore.QSize(15, 15)

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