QApplication 关闭窗口 进程还在运行

当你关闭一个Qt窗口时，QApplication并不会自动退出。这意味着你需要手动调用QApplication的quit()函数来终止应用程序。例如，在你的窗口的closeEvent()事件处理程序中添加以下代码：

def closeEvent(self, event):
    reply = QMessageBox.question(self, 'Message', "Are you sure you want to quit?", QMessageBox.Yes | QMessageBox.No, QMessageBox.No)
    if reply == QMessageBox.Yes:
        event.accept()
        QApplication.quit()
    else:
        event.ignore()

当用户点击关闭按钮时，会显示一个消息框，询问用户是否真的要退出。如果用户确认退出，则调用QApplication的quit()函数来终止应用程序。

相关问题

请用python，pyqt5写一个UI界面代码，具有如下功能：1.一个widget主窗口，包含5个子窗口；2.开启一个子进程，一个窗口显示mlx90640动态色温图，一个窗口显示最大温度随时间的变化曲线图；3.开启一个子进程，一个窗口显示usb摄像头的动态画面，一个窗口显示图像中物体大小与时间的变化曲线图；4.一个窗口显示程序运行过程中的的print信息，包括主进程和子进程

以下是一个简单的示例代码，实现了上述功能：

import sys
import os
import time
import subprocess

from PyQt5.QtCore import Qt, QTimer
from PyQt5.QtGui import QPixmap
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QHBoxLayout, QLabel, QPushButton, QTextEdit


class MainWidget(QWidget):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("Main Widget")
        self.resize(800, 600)

        self.sub_widgets = []

        layout = QVBoxLayout()

        for i in range(5):
            sub_widget = SubWidget(i)
            self.sub_widgets.append(sub_widget)
            layout.addWidget(sub_widget)

        self.setLayout(layout)


class SubWidget(QWidget):
    def __init__(self, index):
        super().__init__()

        self.setWindowTitle(f"Sub Widget {index + 1}")
        self.resize(400, 300)

        self.process = None

        layout = QVBoxLayout()

        if index == 0:
            # MLX90640 dynamic temperature map
            self.label = QLabel()
            layout.addWidget(self.label)

            self.start_mlx90640()

        elif index == 1:
            # Maximum temperature vs time curve
            self.curve_label = QLabel()
            layout.addWidget(self.curve_label)

            self.start_temperature_curve()

        elif index == 2:
            # USB camera dynamic image
            self.label = QLabel()
            layout.addWidget(self.label)

            self.start_usb_camera()

        elif index == 3:
            # Object size vs time curve
            self.curve_label = QLabel()
            layout.addWidget(self.curve_label)

            self.start_object_size_curve()

        elif index == 4:
            # Print information
            self.text_edit = QTextEdit()
            self.text_edit.setReadOnly(True)
            layout.addWidget(self.text_edit)

        self.setLayout(layout)

    def start_mlx90640(self):
        # Start a subprocess to run the mlx90640 program
        self.process = subprocess.Popen(["python", "mlx90640.py"], stdout=subprocess.PIPE)

        # Read the temperature map from stdout and update the label
        timer = QTimer(self)
        timer.timeout.connect(lambda: self.update_label(self.label, self.process.stdout))
        timer.start(50)

    def start_temperature_curve(self):
        # Start a subprocess to run the temperature curve program
        self.process = subprocess.Popen(["python", "temperature_curve.py"], stdout=subprocess.PIPE)

        # Read the curve image from stdout and update the label
        timer = QTimer(self)
        timer.timeout.connect(lambda: self.update_label(self.curve_label, self.process.stdout))
        timer.start(50)

    def start_usb_camera(self):
        # Start a subprocess to run the usb camera program
        self.process = subprocess.Popen(["python", "usb_camera.py"], stdout=subprocess.PIPE)

        # Read the camera image from stdout and update the label
        timer = QTimer(self)
        timer.timeout.connect(lambda: self.update_label(self.label, self.process.stdout))
        timer.start(50)

    def start_object_size_curve(self):
        # Start a subprocess to run the object size curve program
        self.process = subprocess.Popen(["python", "object_size_curve.py"], stdout=subprocess.PIPE)

        # Read the curve image from stdout and update the label
        timer = QTimer(self)
        timer.timeout.connect(lambda: self.update_label(self.curve_label, self.process.stdout))
        timer.start(50)

    def update_label(self, label, stdout):
        # Read one line from stdout
        line = stdout.readline().decode().strip()

        if not line:
            # Process has ended
            label.setText("Process ended.")
            return

        if label.width() == 0 or label.height() == 0:
            # Label has not been shown yet, wait for it to be shown
            return

        if label.pixmap() is None:
            # Create a new pixmap
            pixmap = QPixmap(label.width(), label.height())
            pixmap.fill(Qt.white)
            label.setPixmap(pixmap)

        # Draw the image or curve on the pixmap
        if line.startswith("image:"):
            pixmap = QPixmap.fromImage(QImage.fromData(line[6:].encode()))
            label.setPixmap(pixmap)

        elif line.startswith("curve:"):
            pixmap = QPixmap.fromImage(QImage.fromData(line[6:].encode()))
            label.setPixmap(pixmap)

        else:
            # Append the line to the text edit
            self.text_edit.append(line)

    def closeEvent(self, event):
        if self.process is not None and self.process.poll() is None:
            # Terminate the subprocess if it is still running
            self.process.terminate()
            self.process.wait()

        super().closeEvent(event)


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

    main_widget = MainWidget()
    main_widget.show()

    sys.exit(app.exec_())

说明：

- 程序开启了一个 `MainWidget`，包含了 5 个子窗口 `SubWidget`。
- 对于每个子窗口 `SubWidget`，程序开启了一个子进程来运行对应的程序，并通过定时器和标签控件来显示程序输出的图片或曲线。
- 当 `SubWidget` 被关闭时，程序会终止对应的子进程。

pyqt5如何实现点击窗体关闭图标进程仍在

在PyQt5中，当用户点击窗口的关闭图标（通常表现为X形状）时，默认的行为是关闭整个应用程序或窗口。如果你想让窗口关闭但保持进程运行，可以在槽函数`closeEvent()`中处理这个情况。这里是一个简单的例子：

from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import Qt

class MyWindow(QMainWindow):
    def closeEvent(self, event):  # 捕获关闭事件
        print("窗口即将关闭...")
        # 如果你需要做清理工作或者保存数据，可以在这里操作
        # 然后阻止事件的默认处理（关闭窗口）
        event.ignore()  # 设置event.accept()将正常关闭窗口
        # 或者设置event.setAccepted(False)同样阻止关闭
        self.showMinimized()  # 替换为showNormal()或其他的最小化操作

if __name__ == "__main__":
    app = QApplication([])
    window = MyWindow()
    window.setWindowTitle("我的窗口")
    window.show()
    app.exec_()

在这个例子中，当你点击关闭按钮时，会打印一条消息并进入最小化状态而不是完全关闭。你可以在此基础上根据需要添加额外的操作。