如何在PyQt5中用另一个小部件替换小部件

Question

在我的GUI应用程序中，我向用户显示一个摄像头流。现在的问题是，用户一次只能看到来自一个摄像机的流，为了看到来自其他摄像机的流，他必须输入新摄像机的凭证，如username、password和camera IP

我想使用对话框执行此操作。我能做到，但每次都会有一扇新窗户弹出。我知道如何使用QStackedLayout在不同的相机之间切换，但这次我不能使用，因为相机对象是在运行时创建的

我想要的是，按下一个按钮，就会出现一个对话框，输入凭证后必须更换相机

代码：

from PyQt5 import QtCore, QtGui, QtWidgets
from threading import Thread
from collections import deque
from datetime import datetime
import time
import sys
import cv2
import imutils

class CameraWidget(QtWidgets.QWidget):
    """Independent camera feed
    Uses threading to grab IP camera frames in the background

    @param width - Width of the video frame
    @param height - Height of the video frame
    @param stream_link - IP/RTSP/Webcam link
    @param aspect_ratio - Whether to maintain frame aspect ratio or force into fraame
    """

    def __init__(self, username, password, camera_ip, width=0, height=0, stream_link=0, aspect_ratio=False, parent=None, deque_size=1):
        super(CameraWidget, self).__init__(parent)

        # Initialize deque used to store frames read from the stream
        self.deque = deque(maxlen=deque_size)

        # Slight offset is needed since PyQt layouts have a built in padding
        # So add offset to counter the padding 
        self.screen_width = 640
        self.screen_height = 480
        self.maintain_aspect_ratio = aspect_ratio

        self.camera_stream_link = 'rtsp://{}:{}@{}/Streaming/Channels/2'.format(username, password, camera_ip)

        # Flag to check if camera is valid/working
        self.online = False
        self.capture = None
        self.video_frame = QtWidgets.QLabel()

        self.load_network_stream()

        # Start background frame grabbing
        self.get_frame_thread = Thread(target=self.get_frame, args=())
        self.get_frame_thread.daemon = True
        self.get_frame_thread.start()

        # Periodically set video frame to display
        self.timer = QtCore.QTimer()
        self.timer.timeout.connect(self.set_frame)
        self.timer.start(.5)

        print('Started camera: {}'.format(self.camera_stream_link))

    def load_network_stream(self):
        """Verifies stream link and open new stream if valid"""

        def load_network_stream_thread():
            if self.verify_network_stream(self.camera_stream_link):
                self.capture = cv2.VideoCapture(self.camera_stream_link)
                self.online = True
        self.load_stream_thread = Thread(target=load_network_stream_thread, args=())
        self.load_stream_thread.daemon = True
        self.load_stream_thread.start()

    def verify_network_stream(self, link):
        """Attempts to receive a frame from given link"""

        cap = cv2.VideoCapture(link)
        if not cap.isOpened():
            return False
        cap.release()
        return True

    def get_frame(self):
        """Reads frame, resizes, and converts image to pixmap"""

        while True:
            try:
                if self.capture.isOpened() and self.online:
                    # Read next frame from stream and insert into deque
                    status, frame = self.capture.read()
                    if status:
                        self.deque.append(frame)
                    else:
                        self.capture.release()
                        self.online = False
                else:
                    # Attempt to reconnect
                    print('attempting to reconnect', self.camera_stream_link)
                    self.load_network_stream()
                    self.spin(2)
                self.spin(.001)
            except AttributeError:
                pass

    def spin(self, seconds):
        """Pause for set amount of seconds, replaces time.sleep so program doesnt stall"""

        time_end = time.time() + seconds
        while time.time() < time_end:
            QtWidgets.QApplication.processEvents()

    def set_frame(self):
        """Sets pixmap image to video frame"""

        if not self.online:
            self.spin(1)
            return

        if self.deque and self.online:
            # Grab latest frame
            frame = self.deque[-1]

            # Keep frame aspect ratio
            if self.maintain_aspect_ratio:
                self.frame = imutils.resize(frame, width=self.screen_width)
            # Force resize
            else:
                self.frame = cv2.resize(frame, (self.screen_width, self.screen_height))
                self.frame = cv2.cvtColor(self.frame, cv2.COLOR_BGR2RGB)
                h, w, ch = self.frame.shape
                bytesPerLine = ch * w

            # Convert to pixmap and set to video frame
            self.img = QtGui.QImage(self.frame, w, h, bytesPerLine, QtGui.QImage.Format_RGB888)
            self.pix = QtGui.QPixmap.fromImage(self.img)
            self.video_frame.setPixmap(self.pix)

    def get_video_frame(self):
        return self.video_frame


class MainWindow(QtWidgets.QMainWindow):

    def __init__(self, username, password, camera_ip, parent=None):
        super(MainWindow, self).__init__(parent)

        # Top frame
        self.top_frame = QtWidgets.QFrame()
        self.top_frame.setStyleSheet("background-color: rgb(153, 187, 255)")

        self.camera = CameraWidget(username, password, camera_ip)
        self.top_layout = QtWidgets.QHBoxLayout()
        self.top_layout.addWidget(self.camera.get_video_frame())
        self.top_frame.setLayout(self.top_layout)


        # Bottom frame
        self.btm_frame = QtWidgets.QFrame()
        self.btm_frame.setStyleSheet("background-color: rgb(208, 208, 225)")

        self.button = QtWidgets.QPushButton('Change Camera')
        self.button.clicked.connect(self.onClick)
        self.btm_layout = QtWidgets.QHBoxLayout()
        self.btm_layout.addStretch()
        self.btm_layout.addWidget(self.button)
        self.btm_layout.setContentsMargins(5, 5, 5, 5)
        self.btm_frame.setLayout(self.btm_layout)


        self.widget = QtWidgets.QWidget()
        self.layout = QtWidgets.QVBoxLayout()
        self.layout.addWidget(self.top_frame, 20)
        self.layout.addWidget(self.btm_frame,1)
        self.layout.setContentsMargins(0, 0, 0, 0)
        self.layout.setSpacing(0)
        self.widget.setLayout(self.layout)
        self.setCentralWidget(self.widget)

    def onClick(self):
        """
        I want this function to open a dialog box
        asking user to enter new cameras credentials
        and display it.
        """


if __name__ == '__main__':

    # Create main application window
    app = QtWidgets.QApplication([])
    app.setStyle(QtWidgets.QStyleFactory.create("Fusion"))
    w = MainWindow('admin', 'vaaan@123', '192.168.1.51')
    w.showMaximized()
    sys.exit(app.exec_())

Answer 1

初步答复

这和你的想法接近吗

from PyQt5 import QtCore, QtGui, QtWidgets
from threading import Thread
from collections import deque
from datetime import datetime
import time
import sys
import cv2
import imutils

class CameraWidget(QtWidgets.QWidget):
    # no change
    ...


class ChangeDialog(QtWidgets.QDialog):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, *kwargs)
        QBtn = QtWidgets.QDialogButtonBox.Ok | QtWidgets.QDialogButtonBox.Cancel
        
        buttonBox = QtWidgets.QDialogButtonBox(QBtn)
        buttonBox.accepted.connect(self.accept)
        buttonBox.rejected.connect(self.reject)

        self.layout = QtWidgets.QVBoxLayout()

        self.setLayout(self.layout)

        vlayout = QtWidgets.QVBoxLayout()
        self.usernameEdit = QtWidgets.QLineEdit()
        self.passwordEdit = QtWidgets.QLineEdit()
        self.passwordEdit.setEchoMode(QtWidgets.QLineEdit.Password)
        self.ipAddrEdit = QtWidgets.QLineEdit()
        vlayout.addWidget(self.usernameEdit)
        vlayout.addWidget(self.passwordEdit)
        vlayout.addWidget(self.ipAddrEdit)

        self.layout.addLayout(vlayout)
        self.layout.addWidget(buttonBox)

    @property
    def username(self):
        return self.usernameEdit.text()

    @property
    def password(self):
        return self.passwordEdit.text()

    @property
    def ipAddress(self):
        return self.ipAddrEdit.text()


class MainWindow(QtWidgets.QMainWindow):

    def __init__(self, username, password, camera_ip, parent=None):
        super(MainWindow, self).__init__(parent)

        # Top frame
        self.top_frame = QtWidgets.QFrame()
        self.top_frame.setStyleSheet("background-color: rgb(153, 187, 255)")

        self.camera = CameraWidget(username, password, camera_ip)
        self.top_layout = QtWidgets.QHBoxLayout()
        self.top_layout.addWidget(self.camera.get_video_frame())
        self.top_frame.setLayout(self.top_layout)


        # Bottom frame
        self.btm_frame = QtWidgets.QFrame()
        self.btm_frame.setStyleSheet("background-color: rgb(208, 208, 225)")

        self.button = QtWidgets.QPushButton('Change Camera')
        self.button.clicked.connect(self.onClick)
        self.btm_layout = QtWidgets.QHBoxLayout()
        self.btm_layout.addStretch()
        self.btm_layout.addWidget(self.button)
        self.btm_layout.setContentsMargins(5, 5, 5, 5)
        self.btm_frame.setLayout(self.btm_layout)


        self.widget = QtWidgets.QWidget()
        self.layout = QtWidgets.QVBoxLayout()
        self.layout.addWidget(self.top_frame, 20)
        self.layout.addWidget(self.btm_frame,1)
        self.layout.setContentsMargins(0, 0, 0, 0)
        self.layout.setSpacing(0)
        self.widget.setLayout(self.layout)
        self.setCentralWidget(self.widget)

        self.changeDialog = ChangeDialog()
        self.changeDialog.accepted.connect(self.changeCamera)


    def changeCamera(self):
        self.camera = CameraWidget(
            self.changeDialog.username,
            self.changeDialog.password,
            self.changeDialog.ipAddress)
        # not sure if this is necessary
        self.top_layout.takeAt(0)
        self.top_layout.addWidget(self.camera.get_video_frame())

    def onClick(self):
        """
        I want this function to open a dialog box
        asking user to enter new cameras credentials
        and display it.
        """
        self.changeDialog.exec()


if __name__ == '__main__':

    # Create main application window
    app = QtWidgets.QApplication([])
    app.setStyle(QtWidgets.QStyleFactory.create("Fusion"))
    w = MainWindow('admin', 'vaaan@123', '192.168.1.51')
    w.showMaximized()
    sys.exit(app.exec_())

如果看不到什么东西，很难判断是否有什么东西丢失了，但这应该是正确的方向

答复意见

关于必填字段

首先，这个建议很粗糙

您应该在每次QLineEdit之前添加QLabel

然后，您应该编写一些验证逻辑。您可以通过删除我放入的默认“OK”按钮并放入您自己的按钮来完成此操作。按下此按钮时，检查每个输入self（对话框）是否有效

如果是这种情况，您可以调用^{}。否则，您可以对无效的第一个输入使用^{}

显示以前输入的数据

在我的提案中，我创建了一个与主窗口一起存储的对话框

它从未被销毁，因此所有数据仍然有效。当您第二次显示该对话框时，它仍然保存以前的数据

如果愿意，您可以每次创建一个新的对话框对象，或者清除所有输入