我的打印图未显示在pyqt5.QtWidgets中

Question

我目前正在学习如何将pyqt5与matplotlib一起使用，因此实现此代码，当我按下另一个窗口中的按钮后，该代码将弹出

我创建了另一个名为canvas的类，以便将来创建多个图形，如条形图和直方图

当我运行此代码时，窗口将出现，按钮也将出现，但不是我创建的画布

如何在主窗口中显示画布（饼图）

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import numpy as np
import PyQt5
from PyQt5 import QtCore, QtGui, QtWidgets
import sys

class window(QtWidgets.QMainWindow):
    def setupUi(self,Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(900, 500)

        self.pushButton = QtWidgets.QPushButton(Dialog)
        self.pushButton.setGeometry(QtCore.QRect(0, 380, 141, 61))
        self.pushButton.setObjectName("pushButton")
        

        self.canvas = Canvas(self, width=8, height=4)
        self.canvas.move(0,0)

 
        self.retranslateUi(Dialog)
        QtCore.QMetaObject.connectSlotsByName(Dialog)
        
        

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "output window"))


class Canvas(FigureCanvas):
    def __init__(self, parent = None, width = 5, height = 5, dpi = 100):
        fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = fig.add_subplot(111)

        FigureCanvas.__init__(self, fig)
        self.setParent(parent)
      
        self.plot()

    def plot(self):

        x = np.array([50, 30,40])
        labels = ["Apples", "Bananas", "Melons"]
        ax = self.figure.add_subplot(111)
        ax.pie(x, labels=labels)
        

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    Dialog = QtWidgets.QDialog()
    ui = window()
    ui.setupUi(Dialog)
    Dialog.show()
    sys.exit(app.exec_())

Answer 1

造成此问题的原因是，您正在修改Qt Designer生成的代码，而不了解其后果。QtDesigner生成的类不是窗口，而是一个只填充窗口的类。例如，在窗口修改的情况下，QMainWindow具有画布，但您已经创建了另一个名为Dialog的小部件，该小部件就是您显示的小部件（如果您选中QPushButton，则它是Dialog的子部件，因此也会显示）。另一方面，您只需创建一个轴

因此，您不应该修改QtDesigner生成的类，而应该创建从小部件继承的另一个类，并使用前一个类填充它

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import numpy as np
import PyQt5
from PyQt5 import QtCore, QtGui, QtWidgets
import sys


class Ui_Dialog:
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(900, 500)

        self.pushButton = QtWidgets.QPushButton(Dialog)
        self.pushButton.setGeometry(QtCore.QRect(0, 380, 141, 61))
        self.pushButton.setObjectName("pushButton")

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "output window"))


class Canvas(FigureCanvas):
    def __init__(self, parent=None, width=5, height=5, dpi=100):
        fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = fig.add_subplot(111)
        FigureCanvas.__init__(self, fig)
        self.setParent(parent)
        self.plot()

    def plot(self):
        x = np.array([50, 30, 40])
        labels = ["Apples", "Bananas", "Melons"]
        self.axes.pie(x, labels=labels)
        self.draw()


class Dialog(QtWidgets.QDialog, Ui_Dialog):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)

        self.canvas = Canvas(self, width=8, height=4)
        self.canvas.move(0, 0)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    w = Dialog()
    w.show()
    sys.exit(app.exec_())