如何选择视频播放器文件

Question

我是新来的类和PyQt5并试图建立使用PyQt5和OpenCV视频播放器。使用OpenCV Video Capture with PyQt4代码并进行更改，以命令转换PyQt4中成PyQt5并增加了暂停按钮，我现在有暂停，播放端的视频播放器，并退出按钮。这是工作正常的代码：

import cv2
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QApplication, QPushButton, 
QVBoxLayout, QFileDialog

fileName = 'C:/Users/Art/Downloads/testVideo.mp4'


class Capture():
    def __init__(self):
        self.capturing = False
        self.c = cv2.VideoCapture(fileName)

    def startCapture(self):
        self.capturing = True
        cap = self.c
        while(self.capturing):
            ret, frame = cap.read()
            cv2.imshow("Capture", frame)
            cv2.waitKey(5)
        cv2.destroyAllWindows()

    def endCapture(self):
        self.capturing = False

    def pauseCapture(self): 
        if cv2.waitKey(0) & 0xFF == ord('p'):  # Pause
            self.capturing = False

    def quitCapture(self):
        cap = self.c
        cv2.destroyAllWindows()
        cap.release()
        QtCore.QCoreApplication.quit()

class Window(QtWidgets.QWidget):
    def __init__(self):

    QtWidgets.QWidget.__init__(self)
    self.setWindowTitle('Control Panel')

    self.capture = Capture()
    self.start_button = QPushButton('Start', self)
    self.start_button.clicked.connect(self.capture.startCapture)

    self.end_button = QPushButton('End', self)
    self.end_button.clicked.connect(self.capture.endCapture)

    self.pause_button = QPushButton('Pause', self)
    self.pause_button.clicked.connect(self.capture.pauseCapture)

    self.quit_button = QPushButton('Quit', self)
    self.quit_button.clicked.connect(self.capture.quitCapture)

    vbox = QVBoxLayout(self)
    vbox.addWidget(self.start_button)
    vbox.addWidget(self.end_button)
    vbox.addWidget(self.pause_button)
    vbox.addWidget(self.quit_button)

    self.setLayout(vbox)
    self.setGeometry(100, 100, 200, 200)
    self.show()

    if __name__== '__main__':
        import sys
        app = QApplication(sys.argv)
        window = Window()
        sys.exit(app.exec())

到目前为止，我硬编码的视频文件的名称和路径到代码（文件名）。现在，我想添加加载按钮，可以让用户选择视频。事情是这样的：

 self.load_button = QPushButton('Load', self)
 self.load_button.clicked.connect(self.pick_video)

 def pick_video():
     dialog = QtGui.QFileDialog()
     fileName = dialog.getExistingDirectory(None, 
      "Select Folder")
     return fileName

并加入负载按钮现有的按钮，像这样的列表：

vbox.addWidget(self.load_button)

我的问题是我不知道我怎么能合并到现有的代码这一点。如果我把它里面Window类，它抛出我的错误。我的问题是如何添加像这样到我现有的代码，使得用户可以按下加载按钮后，选择视频文件。

编辑：根据@ekhumoro改变代码后，我得到了这样的事情：

import cv2
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QApplication, QPushButton, 
QVBoxLayout, QFileDialog


class Capture():
    def __init__(self):
        self.capturing = False

    def startCapture(self, path):
        self.capturing = True
        self.c = cv2.VideoCapture(path)
        while self.capturing:
            ret, frame = self.c.read()
            cv2.imshow("Capture", frame)
            cv2.waitKey(5)
        cv2.destroyAllWindows()

    def endCapture(self):
        self.capturing = False

    def pauseCapture(self): 
        if cv2.waitKey(0) & 0xFF == ord('p'):  # Pause
            self.capturing = False

    def quitCapture(self):
        cap = self.c
        cv2.destroyAllWindows()
        cap.release()
        QtCore.QCoreApplication.quit()

class Window(QtWidgets.QWidget):
    def __init__(self):

        QtWidgets.QWidget.__init__(self)
        self.setWindowTitle('Control Panel')

        self.capture = Capture()
        self.start_button = QPushButton('Start', self)
        self.start_button.clicked.connect(self.start)

        self.end_button = QPushButton('End', self)
        self.end_button.clicked.connect(self.capture.endCapture)

        self.pause_button = QPushButton('Pause', self)
        self.pause_button.clicked.connect(self.capture.pauseCapture)

        self.quit_button = QPushButton('Quit', self)
        self.quit_button.clicked.connect(self.capture.quitCapture)

        vbox = QVBoxLayout(self)
        vbox.addWidget(self.start_button)
        vbox.addWidget(self.end_button)
        vbox.addWidget(self.pause_button)
        vbox.addWidget(self.quit_button)

        self.setLayout(vbox)
        self.setGeometry(100, 100, 200, 200)
        self.show()

    def start(self):
        path = QtWidgets.QFileDialog.getOpenFileName(self)[0]
        if path:
            self.capture.startCapture(path)

if __name__== '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    sys.exit(app.exec())

但是，当我运行此代码，我得到这个错误：AttributeError的：“窗口”对象有没有属性“开始”。另一件事是，我想为这个过程中一个单独的按钮，这意味着一旦用户运行代码，在打开时，他/她可以点击该按钮的窗口（我们称之为加载按钮），然后选择视频文件，我不要在此代码中看到。我缺少的东西的地方？或者，也许将重新排列的代码是不是@ekhumoro意思。

Answer 1

重新排列代码，以便startCapture需要path参数。然后通过从在启动按钮插槽中的文件对话框的路径：

class Capture():
    def __init__(self):
        self.capturing = False

    def startCapture(self, path):
        self.capturing = True
        self.c = cv2.VideoCapture(path)
        while self.capturing:
            ret, frame = self.c.read()
            cv2.imshow("Capture", frame)
            cv2.waitKey(5)
        cv2.destroyAllWindows()

class Window(QtWidgets.QWidget):
    def __init__(self):
        ...
        self.start_button = QPushButton('Start', self)
        self.start_button.clicked.connect(self.start)
        ...

    def start(self):
        path = QtWidgets.QFileDialog.getOpenFileName(self)[0]
        if path:
            self.capture.startCapture(path)

下面是一个完整的替代实现：

import cv2
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QApplication, QPushButton,QVBoxLayout, QFileDialog

class Capture():
    def __init__(self):
        self.capturing = False
        self.c = None

    def setVideoFile(self, path):
        if self.c is not None:
            cv2.destroyAllWindows()
            self.c.release()
        self.c = cv2.VideoCapture(path)
        self.startCapture()

    def startCapture(self):
        self.capturing = True
        cap = self.c
        while(self.capturing):
            ret, frame = cap.read()
            cv2.imshow("Capture", frame)
            cv2.waitKey(5)
        cv2.destroyAllWindows()

    def endCapture(self):
        self.capturing = False

    def pauseCapture(self):
        if cv2.waitKey(0) & 0xFF == ord('p'):  # Pause
            self.capturing = False

    def quitCapture(self):
        cap = self.c
        cv2.destroyAllWindows()
        cap.release()
        QtCore.QCoreApplication.quit()

class Window(QtWidgets.QWidget):
    def __init__(self):
        QtWidgets.QWidget.__init__(self)
        self.setWindowTitle('Control Panel')

        self.capture = Capture()
        self.open_button = QPushButton('Open', self)
        self.open_button.clicked.connect(self.open)

        self.start_button = QPushButton('Start', self)
        self.start_button.clicked.connect(self.capture.startCapture)

        self.end_button = QPushButton('End', self)
        self.end_button.clicked.connect(self.capture.endCapture)

        self.pause_button = QPushButton('Pause', self)
        self.pause_button.clicked.connect(self.capture.pauseCapture)

        self.quit_button = QPushButton('Quit', self)
        self.quit_button.clicked.connect(self.capture.quitCapture)

        vbox = QVBoxLayout(self)
        vbox.addWidget(self.open_button)
        vbox.addWidget(self.start_button)
        vbox.addWidget(self.end_button)
        vbox.addWidget(self.pause_button)
        vbox.addWidget(self.quit_button)

        self.setLayout(vbox)
        self.setGeometry(100, 100, 200, 200)
        self.show()

    def open(self):
        path = QtWidgets.QFileDialog.getOpenFileName(self)[0]
        if path:
            self.capture.setVideoFile(path)

if __name__== '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    sys.exit(app.exec())