PyQt6 线程管理：优雅地终止长时间运行的任务与信号处理机制解析

class ThreadTwo(QObject):
    # ...
    def run(self):
        i = 0
        while True: # 这是一个阻塞循环
            if self.if_finished or i == 99:
                self.progress_signal.emit(i)
                return
            i += 1
            self.progress_signal.emit(i)
            time.sleep(0.1) # 虽然有sleep，但没有处理事件

import sys
import time
from PyQt6.QtCore import QObject, pyqtSignal, QThread
from PyQt6.QtWidgets import QApplication, QMainWindow, QProgressBar, QPushButton

class ThreadTwo(QObject):
    finished_signal = pyqtSignal()
    progress_signal = pyqtSignal(int)

    def __init__(self):
        self.if_finished = False
        super().__init__()

    def run(self):
        i = 0
        while True:
            QApplication.processEvents() # 关键：处理线程事件
            if self.if_finished or i >= 99: # 修改为i >= 99以确保达到100%
                self.progress_signal.emit(i)
                return
            i += 1
            self.progress_signal.emit(i)
            time.sleep(0.1)

    def finished(self):
        self.finished_signal.emit()

    def reset(self):
        self.if_finished = False

    def stop(self):
        print("stop")
        self.if_finished = True

# ... (MainWindow 及其他代码保持不变，或根据需要进行调整)

import sys
import random

from PyQt6.QtCore import QObject, pyqtSignal, QThread
from PyQt6.QtWidgets import (
    QApplication, QMainWindow, QProgressBar, QPushButton,
    QWidget, QHBoxLayout,
    )

# 工作者类一：模拟长时间运行任务
class WorkerOne(QObject):
    finished = pyqtSignal() # 任务完成信号

    def run(self):
        delay = random.randint(25, 50) # 随机延迟模拟耗时操作
        for i in range(100):
            QThread.msleep(delay) # 使用QThread.msleep() 进行非阻塞延迟
        self.finished.emit() # 任务完成后发出信号

# 工作者类二：模拟进度更新任务
class WorkerTwo(QObject):
    progress = pyqtSignal(int) # 进度更新信号

    def run(self):
        self._stopped = False # 内部停止标志
        for i in range(1, 101):
            QThread.msleep(50) # 非阻塞延迟
            if not self._stopped: # 检查停止标志
                self.progress.emit(i)
            else:
                self.progress.emit(100) # 停止时确保进度达到100%
                break # 退出循环

    def stop(self):
        print('WorkerTwo stop signal received')
        self._stopped = True # 设置停止标志

# 主窗口类
class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("PyQt6 线程管理示例")
        self.setGeometry(600, 200, 400, 50)

        # UI 布局
        widget = QWidget()
        layout = QHBoxLayout(widget)
        self.btn = QPushButton("开始")
        self.bar = QProgressBar()
        layout.addWidget(self.bar)
        layout.addWidget(self.btn)
        self.setCentralWidget(widget)
        self.btn.clicked.connect(self.start)

        # 线程一设置
        self.thread_one = QThread()
        self.worker_one = WorkerOne()
        self.worker_one.moveToThread(self.thread_one) # 将工作者对象移到新线程
        self.thread_one.started.connect(self.worker_one.run) # 线程启动时调用工作者run方法
        self.worker_one.finished.connect(self.handle_finished) # 任务完成后的处理

        # 线程二设置
        self.thread_two = QThread()
        self.worker_two = WorkerTwo()
        self.worker_two.moveToThread(self.thread_two)
        self.thread_two.started.connect(self.worker_two.run)
        self.worker_two.progress.connect(self.bar.setValue) # 进度更新

    def start(self):
        # 避免重复启动线程
        if not (self.thread_one.isRunning() or
                self.thread_two.isRunning()):
            self.bar.setValue(0) # 重置进度条
            self.thread_one.start()
            self.thread_two.start()

    def handle_finished(self):
        # 当WorkerOne完成时，停止WorkerTwo
        self.worker_two.stop()
        self.reset_threads() # 重置并清理线程

    def reset_threads(self):
        # 优雅地终止线程
        if self.thread_one.isRunning():
            self.thread_one.quit() # 请求线程退出事件循环
            self.thread_one.wait() # 等待线程真正退出
        if self.thread_two.isRunning():
            self.thread_two.quit()
            self.thread_two.wait()

    def closeEvent(self, event):
        # 窗口关闭时确保线程被终止
        self.reset_threads()
        event.accept()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec())