如何在 PyQt5 中用另一个小部件替换一个小部件
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【中文标题】如何在 PyQt5 中用另一个小部件替换一个小部件【英文标题】：How to replace a widget with another in PyQt5 【发布时间】：2020-08-22 15:47:09 【问题描述】：在我的 GUI 应用程序中，我正在向用户显示摄像机流。现在的问题是，用户一次只能看到来自一台摄像机的流，并且为了看到来自其他摄像机的流，他必须输入新摄像机的凭据，例如 username、password 和 camera IP .
我想使用对话框来执行此操作。我能够做到这一点，但每次都会弹出一个新窗口。我如何使用QStackedLayout 在不同的相机之间切换，但这次我不能使用它，因为相机对象是在运行时创建的。
我只想在按下按钮时出现一个对话框，并且在输入凭据后必须更换相机。
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_())
【问题讨论】：
【参考方案1】：初步回答
这是否接近您的想法？
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_())
如果不能真正看到某些东西，很难判断是否缺少某些东西，但这应该是正确的方向。
回答cmets
关于必填字段
首先这个提议很粗糙。
您应该在每个 QLineEdit 之前添加 QLabels。
然后你应该编写一些验证逻辑。您可以通过删除我放入的默认“确定”按钮并放置您自己的按钮来做到这一点。按下此按钮时，您会检查每个输入 self（对话框）是否有效。
如果是这种情况，您可以致电accept()。否则，您可以在第一个无效的输入上使用setFocus()。
显示之前输入的数据
在我的提议中，我创建了一个与 MainWindow 一起存储的对话框。
它永远不会被破坏，因此所有数据仍然存在。当您第二次显示该对话框时，它仍然保留以前的数据。
如果您愿意，可以每次都创建一个新的对话框对象，或者清除所有输入。
【讨论】：
你能把所有这些输入字段都设为必填吗？以及如何在QLineEdit() 中显示以前输入的值？以上是关于如何在 PyQt5 中用另一个小部件替换一个小部件的主要内容，如果未能解决你的问题，请参考以下文章
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