Question

我正在尝试使用嵌入QT小部件中的matplotlibs更新多个图。现在，我可以在窗口中更新一个绘图。但是，当我尝试通过单击按钮切换到其他图时，程序将冻结。

这是一个测试脚本，我正在使用它了解如何使用编程工具将其集成到更大的程序中。我修改了以下问题的代码：How to embed matplotlib in pyqt - for Dummies

我已经在这个问题上停留了一段时间了。我知道我缺少一些非常简单的东西。


import random
import sys
from PyQt4 import QtGui, QtCore

from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QT as NavigationToolbar
from matplotlib.figure import Figure

class Window(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)

        # a figure instance to plot on
        self.figure1 = Figure()
        self.figure2 = Figure()
        self.current = "fig1"
        # this is the Canvas Widget that displays the `figure`
        # it takes the `figure` instance as a parameter to __init__
        self.canvas = FigureCanvas(self.figure1)
        self.ax1 = self.figure1.add_subplot(111)
        self.ax2 = self.figure2.add_subplot(111)
        self.line1, = self.ax1.plot([], [], 'r', lw=2)
        self.line2, = self.ax2.plot([], [], 'b', lw=2)
        # this is the Navigation widget
        # it takes the Canvas widget and a parent
        self.toolbar = NavigationToolbar(self.canvas, self)

        # Just some button connected to `plot` method
        self.button = QtGui.QPushButton('Plot')
        self.button.clicked.connect(self.plot)

        # set the layout
        layout = QtGui.QVBoxLayout()
        layout.addWidget(self.toolbar)
        layout.addWidget(self.canvas)
        layout.addWidget(self.button)
        self.setLayout(layout)
        self.update()


    def update(self):
        datax = [random.random() for i in range(10)]
        datay = [random.random() for i in range(10)]

        self.line1.set_xdata(datax)
        self.line1.set_ydata(datay)
        self.ax1.relim()
        self.ax1.autoscale_view()


        self.line2.set_xdata(datax)
        self.line2.set_ydata(datay)
        self.ax2.relim()
        self.ax2.autoscale_view()
        self.canvas.draw()
        QtCore.QTimer.singleShot(1, self.update)




    def plot(self):

        if self.current == "fig1":
            self.canvas = FigureCanvas(self.figure2)
            self.current = "fig2"
        elif self.current == "fig2":
            self.canvas = FigureCanvas(self.figure1)
            self.current = "fig1"


if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)

    main = Window()
    main.show()

    sys.exit(app.exec_())

当我单击此按钮时，它应该开始绘制其他图。我没有收到错误消息。

Answer 1

您进行画布更改的逻辑：

def plot(self):
    if self.current == "fig1":
        self.canvas = FigureCanvas(self.figure2)
        self.current = "fig2"
    elif self.current == "fig2":
        self.canvas = FigureCanvas(self.figure1)
        self.current = "fig1"

与以下逻辑类似，

class Foo:
    def __init__(self):
        self.m_a = 0

    def setA(self, a):
        self.m_a = a

    def printA(self):
        print(self.m_a)


class Bar:
    def __init__(self):
        self.a = 5
        self.foo = Foo()
        self.foo.setA(self.a)

    def change(self):
        self.a = 6


if __name__ == "__main__":
    bar = Bar()
    bar.foo.printA()
    bar.change()
    bar.foo.printA()

如果执行了代码，则会得到以下信息：

5
5

如您所见，变量的更改并不意味着会通知其他类，因为变量的名称是昵称，重要的是内存，在这种情况下，所显示的画布占用的内存位置不同于按下按钮时创建的画布，与初始画布关联的line1，line2，ax1和ax2也会发生同样的情况。

另一方面，不建议在GUI中删除和创建窗口小部件，而是最好隐藏一个窗口小部件并显示另一个占据相同空间的窗口小部件，为此，我们可以使用QStackedWidget或QStackedLayout。

import sys
import random
from PyQt4 import QtGui, QtCore

from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import (
    NavigationToolbar2QT as NavigationToolbar,
)
from matplotlib.figure import Figure


class Window(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)

        self.figure1 = Figure()
        self.canvas1 = FigureCanvas(self.figure1)
        self.ax1 = self.figure1.add_subplot(111)
        self.line1, = self.ax1.plot([], [], "r", lw=2)
        self.toolbar1 = NavigationToolbar(self.canvas1, self)

        self.figure2 = Figure()
        self.canvas2 = FigureCanvas(self.figure2)
        self.ax2 = self.figure2.add_subplot(111)
        self.line2, = self.ax2.plot([], [], "b", lw=2)
        self.toolbar2 = NavigationToolbar(self.canvas2, self)

        self.m_stacked_layout = QtGui.QStackedLayout()

        for canvas, toolbar in (
            (self.canvas1, self.toolbar1),
            (self.canvas2, self.toolbar2),
        ):
            widget = QtGui.QWidget()
            lay = QtGui.QVBoxLayout(widget)
            lay.addWidget(toolbar)
            lay.addWidget(canvas)
            self.m_stacked_layout.addWidget(widget)

        self.button = QtGui.QPushButton("Plot", clicked=self.onClicled)

        layout = QtGui.QVBoxLayout(self)
        layout.addLayout(self.m_stacked_layout)
        layout.addWidget(self.button)

        timer = QtCore.QTimer(self, timeout=self.update_plot, interval=1)
        timer.start()
        self.update_plot()

    @QtCore.pyqtSlot()
    def update_plot(self):
        datax = [random.random() for i in range(10)]
        datay = [random.random() for i in range(10)]

        self.line1.set_xdata(datax)
        self.line1.set_ydata(datay)
        self.ax1.relim()
        self.ax1.autoscale_view()

        self.line2.set_xdata(datax)
        self.line2.set_ydata(datay)
        self.ax2.relim()
        self.ax2.autoscale_view()
        self.canvas1.draw()
        self.canvas2.draw()

    @QtCore.pyqtSlot()
    def onClicled(self):
        ix = self.m_stacked_layout.currentIndex()
        self.m_stacked_layout.setCurrentIndex(0 if ix == 1 else 1)


if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)

    main = Window()
    main.show()

    sys.exit(app.exec_())

更新和切换图

1 个答案: