Question

我正在尝试同时运行QVideoWidget和matplotlib动画，

但是当我运行这个py时，QVideoWidget无法正常工作。

我得到了QVideoWidget代码和matplotlib动画代码，然后在下面的代码中将这些代码加在一起。

如果我关闭了matplotlib动画窗口，则QVideoWidget正在运行。

我想知道为什么会这样并解决这个问题

谢谢

import matplotlib.pyplot as plt
import matplotlib.animation as animation
import random
from PyQt5.QtCore import QDir, Qt, QUrl
from PyQt5.QtMultimedia import QMediaContent, QMediaPlayer
from PyQt5.QtMultimediaWidgets import QVideoWidget
from PyQt5.QtWidgets import (QApplication, QFileDialog, QHBoxLayout, QLabel,
    QPushButton, QSizePolicy, QSlider, QStyle, QVBoxLayout, QWidget)
from PyQt5.QtWidgets import QMainWindow,QWidget, QPushButton, QAction
from PyQt5.QtGui import QIcon
import sys
from PyQt5.QtWidgets import (QApplication, QCheckBox, QGridLayout, QGroupBox,
    QMenu, QPushButton, QRadioButton, QVBoxLayout, QWidget)

# Parameters
x_len = 200         # Number of points to display
y_range = [10, 40]  # Range of possible Y values to display

# Create figure for plotting
fig = plt.figure(facecolor='white')
ax = fig.add_subplot(2, 1, 1)
bx = fig.add_subplot(2, 1, 2)
xs = list(range(0, 200))
ys = [0] * x_len
ax.set_ylim(y_range)
bx.set_ylim(y_range)
# Initialize communication with TMP102


# When everything done, release the capture


# Create a blank line. We will update the line in animate
line, = ax.plot(xs, ys)
line2, = bx.plot(xs, ys)
# Add labels
plt.title('TMP102 Temperature over Time')
plt.xlabel('Samples')
plt.ylabel('Temperature (deg C)')
class VideoWindow(QMainWindow):
    def __init__(self, parent=None):

        super(VideoWindow, self).__init__(parent)

        self.setWindowTitle("PyQt Video Player Widget Example - pythonprogramminglanguage.com")

        self.mediaPlayer = QMediaPlayer(None, QMediaPlayer.VideoSurface)

        videoWidget = QVideoWidget()

        self.playButton = QPushButton()
        self.playButton.setEnabled(False)
        self.playButton.setIcon(self.style().standardIcon(QStyle.SP_MediaPlay))
        self.playButton.clicked.connect(self.play)

        self.positionSlider = QSlider(Qt.Horizontal)
        self.positionSlider.setRange(0, 0)
        self.positionSlider.sliderMoved.connect(self.setPosition)

        self.errorLabel = QLabel()
        self.errorLabel.setSizePolicy(QSizePolicy.Preferred,
            QSizePolicy.Maximum)

        # Create new action
        openAction = QAction(QIcon('open.png'), '&Open', self)
        openAction.setShortcut('Ctrl+O')
        openAction.setStatusTip('Open movie')
        openAction.triggered.connect(self.openFile)

        # Create exit action
        exitAction = QAction(QIcon('exit.png'), '&Exit', self)
        exitAction.setShortcut('Ctrl+Q')
        exitAction.setStatusTip('Exit application')
        exitAction.triggered.connect(self.exitCall)

        # Create menu bar and add action
        menuBar = self.menuBar()
        fileMenu = menuBar.addMenu('&File')
        #fileMenu.addAction(newAction)
        fileMenu.addAction(openAction)
        fileMenu.addAction(exitAction)

        # Create a widget for window contents
        wid = QWidget(self)
        self.setCentralWidget(wid)

        # Create layouts to place inside widget
        controlLayout = QHBoxLayout()
        controlLayout.setContentsMargins(0, 0, 0, 0)
        controlLayout.addWidget(self.playButton)
        controlLayout.addWidget(self.positionSlider)
        layout = QVBoxLayout()
        layout.addWidget(videoWidget)
        layout.addLayout(controlLayout)
        layout.addWidget(self.errorLabel)
        # Set widget to contain window contents

        wid.setLayout(layout)

        self.mediaPlayer.setVideoOutput(videoWidget)
        self.mediaPlayer.stateChanged.connect(self.mediaStateChanged)
        self.mediaPlayer.positionChanged.connect(self.positionChanged)
        self.mediaPlayer.durationChanged.connect(self.durationChanged)
        self.mediaPlayer.error.connect(self.handleError)


    def openFile(self):
        fileName, _ = QFileDialog.getOpenFileName(self, "Open Movie",
            QDir.homePath())

        if fileName != '':
            self.mediaPlayer.setMedia(
                QMediaContent(QUrl.fromLocalFile(fileName)))
            self.playButton.setEnabled(True)

    def exitCall(self):
        sys.exit(app.exec_())

    def play(self):
        if self.mediaPlayer.state() == QMediaPlayer.PlayingState:
            self.mediaPlayer.pause()
        else:
            self.mediaPlayer.play()

    def mediaStateChanged(self, state):
        if self.mediaPlayer.state() == QMediaPlayer.PlayingState:
            self.playButton.setIcon(
                self.style().standardIcon(QStyle.SP_MediaPause))
        else:
            self.playButton.setIcon(
                self.style().standardIcon(QStyle.SP_MediaPlay))

    def positionChanged(self, position):
        self.positionSlider.setValue(position)

    def durationChanged(self, duration):
        self.positionSlider.setRange(0, duration)

    def setPosition(self, position):
        self.mediaPlayer.setPosition(position)



    def handleError(self):
        self.playButton.setEnabled(False)
        self.errorLabel.setText("Error: " + self.mediaPlayer.errorString())

    def animate(i, ys):

        # Read temperature (Celsius) from TMP102
        temp_c = random.randint(15, 35)

        # Add y to list
        ys.append(temp_c)

        # Limit y list to set number of items
        ys = ys[-x_len:]

        # Update line with new Y values
        line.set_ydata(ys)
        line2.set_ydata(ys)
        return line, line2,

    ani = animation.FuncAnimation(fig, animate, fargs=(ys,),
                              interval=50,
                              blit=True)

# This function is called periodically from FuncAnimation


# Set up plot to call animate() function periodically



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

    player = VideoWindow()
    player.resize(640, 480)
    player.show()
    plt.show()
    sys.exit(app.exec_())

Answer 1

每个GUI都需要一个事件循环才能更新自身并参加用户事件，操作系统事件等。对于matplotlib，在使用plt.show()时会被调用，而在PyQt5的情况下，当调用{ {1}}。使用当前代码，matplotlib的事件循环将阻止PyQt，因此您无法与PyQt5创建的窗口进行交互。

解决方案很简单，matplotlib支持多个后端，包括PyQt5，因此解决方案就是使用它，在下面的link中，您可以找到一个示例。

考虑到上述情况，以下代码实现了该解决方案：

app.exec_()

如何使用python运行matplotlib和PyQt5 Video

1 个答案: