线程实时日志记录 [英] Threads real-time logging

问题描述

我正在编写一个用于调整照片大小的简单脚本.我想要一个带有文本字段的小部件，在调整每个文件的大小后，消息会出现在其中.

I'm writing a simple script for resizing photos. I'd like to have a widget with text-field in which messages appear after resizing each file.

#!/usr/bin/python3
# -*- coding: utf-8 -*-

import time, sys
from PyQt5.QtCore import pyqtSignal, QThread
from PyQt5.QtWidgets import QApplication, QPushButton, QTextEdit, QWidget, QVBoxLayout

class Thread(QThread):
    log = pyqtSignal(str)
    def __init__(self, parent=None):
        super(Thread, self).__init__(parent)
    def test(self, i):
        time.sleep(1)
        self.log.emit(str(i))

class Widget(QWidget):
    def __init__(self):
        super().__init__()
        self.ui()
    def process(self):
        self.toLog('some text...')
        worker = Thread()
        worker.log.connect(self.toLog)
        for i in range(1, 5):
            worker.test(i)
    def ui(self):
        self.LogOutputTxt = QTextEdit()
        self.LogOutputTxt.setReadOnly(True)
        startBtn = QPushButton('Start')
        startBtn.clicked.connect(self.start)
        layout = QVBoxLayout()
        layout.addWidget(self.LogOutputTxt)
        layout.addWidget(startBtn)
        self.setLayout(layout)
        self.resize(400, 300)
        self.show()
    def start(self):
        self.toLog('start')
        self.process()
    def toLog(self, txt):
        self.LogOutputTxt.append(txt)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ui = Widget()
    sys.exit(app.exec_())

到目前为止，所有文件调整大小后，所有消息立即出现.有什么办法可以一一完成(我是说文件大小已调整，显示的消息等等)?

So far all the messages appear at once after all files are resized. Is there any way to do it one by one (I mean file resized, message displayed, etc.)?

推荐答案

下面是您想要的脚本的重新编写.

Below is a re-write of your script that should do want you want.

但是请注意，这非常简单，并且不会为确保线程安全而过分努力. setItems方法只是对传递给它的数据进行浅表复制-仅对于不可变对象列表确实可以.您还必须确保永远不要在辅助线程内执行任何gui操作，包括对pixmap进行的操作.如果要操作图像，请使用QImage. (并且，如果您想知道如何停止正在运行的线程，请参见例如此答案).

But note that this is quite simplistic, and doesn't try too hard to ensure thread-safety. The setItems method just makes a shallow copy of the data passed to it - which is only really okay for a list of immutable objects. You also must make sure you never do any gui operations inside the worker thread, which includes operations on pixmaps. If you want to manipulate images, use QImage. (And if you want to know how to stop a running thread, see for example this answer).

#!/usr/bin/python3
# -*- coding: utf-8 -*-

import time, sys
from PyQt5.QtCore import pyqtSignal, QThread
from PyQt5.QtWidgets import (
    QApplication, QPushButton, QTextEdit, QWidget, QVBoxLayout
    )

class Thread(QThread):
    log = pyqtSignal(str)

    def __init__(self, parent=None):
        super(Thread, self).__init__(parent)
        self._items = []

    def setItems(self, items):
        if not self.isRunning():
            self._items[:] = items

    def run(self):
        for item in self._items:
            time.sleep(1)
            self.log.emit('processing: %s' % item)

class Widget(QWidget):
    def __init__(self):
        super().__init__()
        self.ui()
        self._worker = Thread(self)
        self._worker.log.connect(self.toLog)
        self._worker.started.connect(lambda: self.toLog('start'))
        self._worker.finished.connect(lambda: self.toLog('finished'))

    def process(self):
        items = ['Image%02d.png' % i for i in range(10)]
        self._worker.setItems(items)
        self._worker.start()

    def ui(self):
        self.LogOutputTxt = QTextEdit()
        self.LogOutputTxt.setReadOnly(True)
        startBtn = QPushButton('Start')
        startBtn.clicked.connect(self.start)
        layout = QVBoxLayout()
        layout.addWidget(self.LogOutputTxt)
        layout.addWidget(startBtn)
        self.setLayout(layout)
        self.resize(400, 300)
        self.show()

    def start(self):
        if not self._worker.isRunning():
            self.process()

    def toLog(self, txt):
        self.LogOutputTxt.append(txt)

if __name__ == '__main__':

    app = QApplication(sys.argv)
    ui = Widget()
    sys.exit(app.exec_())

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