QTimer 在设定时间之前随机停止？

Question

QTimer 对象在接近尾声时随机停止，它不会在同一点左右停止，我不明白为什么它同时停止了自定义小部件和变量本身，所以不是小部件无法显示它。

import sys
from PySide2.QtWidgets import QWidget, QSlider, QLabel, QProgressBar, QPushButton, QHBoxLayout, QVBoxLayout, QApplication
from PyQt5.QtCore import QTimer,Qt
from PySide2extn.RoundProgressBar import roundProgressBar

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

        # Create a slider to set the timer duration
        self.slider = QSlider()
        self.slider.setOrientation(Qt.Horizontal) # vertical slider
        self.slider.setRange(1, 60)  # timer duration range: 1-60 seconds
        self.slider.setValue(10)  # default timer duration: 10 seconds
        self.slider.valueChanged.connect(self.update_label)
        self.time=0

        # Create a label to display the current timer duration
        self.label = QLabel(f'Timer duration: {self.slider.value()} seconds')

        # Create a progress bar to show the timer progress
        self.progress = roundProgressBar()
        self.progress.rpb_setRange(0, self.slider.value() * 1000)
        self.progress.rpb_setValue(0)

        # Create start, stop, and reset buttons
        self.start_button = QPushButton('Start')
        self.stop_button = QPushButton('Stop')
        self.reset_button = QPushButton('Reset')
        self.start_button.clicked.connect(self.start_timer)
        self.stop_button.clicked.connect(self.stop_timer)
        self.reset_button.clicked.connect(self.reset_timer)
        self.stop_button.setEnabled(False)
        self.reset_button.setEnabled(False)

        # Create a layout for the buttons
        button_layout = QHBoxLayout()
        button_layout.addWidget(self.start_button)
        button_layout.addWidget(self.stop_button)
        button_layout.addWidget(self.reset_button)

        # Create a layout and add the slider, label, progress bar, and buttons
        layout = QVBoxLayout()
        layout.addWidget(self.slider)
        layout.addWidget(self.label)
        layout.addWidget(self.progress)
        layout.addLayout(button_layout)
        self.setLayout(layout)

        # Create a timer and set the timeout signal
        self.timer = QTimer()
        self.timer.timeout.connect(self.timeout)
        self.progress_timer = QTimer()
        self.progress_timer.timeout.connect(self.update_progress)

    def update_label(self):
        self.label.setText(f'Timer duration: {self.slider.value()} seconds')
        self.progress.rpb_setRange(0, self.slider.value() * 1000)

    def update_progress(self):
        self.time+=100
        print(self.time)
        self.progress.rpb_setValue(self.time)

    def start_timer(self):
        # Set the timer duration in seconds
        duration = self.slider.value()
        # Start the timer and progress timer
        self.timer.start(duration * 1000)  # milliseconds
        self.progress_timer.start(100)  # 100ms interval
        # Disable the start button, enable the stop and reset buttons
        self.start_button.setEnabled(False)
        self.stop_button.setEnabled(True)
        self.reset_button.setEnabled(True)
        self.slider.setEnabled(False)

    def stop_timer(self):
        # Stop the timer and progress timer
        self.timer.stop()
        self.progress_timer.stop()
        # Disable the stop button, enable the start button
        self.stop_button.setEnabled(False)
        self.start_button.setEnabled(True)
        self.slider.setEnabled(True)

    def reset_timer(self):
        # Stop the timer and progress timer
        self.time=0
        self.timer.stop()
        self.progress_timer.stop()
        # Reset the progress bar to 0, enable the start button, disable the stop and reset buttons
        self.progress.rpb_setValue(0)
        self.start_button.setEnabled(True)
        self.stop_button.setEnabled(False)
        self.reset_button.setEnabled(False)

    def timeout(self):
         # Stop the timer and progress timer
        self.timer.stop()
        self.progress_timer.stop()
        # Disable the stop button, enable the start button and reset button
        self.stop_button.setEnabled(False)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    timer = Timer()
    timer.show()
    sys.exit(app.exec_())

感谢您的帮助。我已经尝试过 PyQt5 和 PySide2 QTImer，尽管它们应该是相同的，但都不起作用。

Answer 1

你计时的方式不准确。 您可以通过进行以下更改来证明这一点：

    def update_progress(self):
        self.time += 100
        duration = self.slider.value() * 1000
        elapsed_time = duration - self.timer.remainingTime()
        print(self.time, elapsed_time)
        self.progress.setValue(elapsed_time)

在打印输出中，您可以看到

self.time

和

elapsed_time

不同步。

self.time

落后，给人的印象是计时器过早停止，而实际上它确实用完了。使用

elapsed_time

作为设置进度条的值将给出计时器的准确进度。 它仍然不会达到 100%，因为计时器超时的时刻将在更新之间进行。如果您降低更新间隔，您将接近 100%。