PyQt5 +日志库

Question

我想将所有日志记录重定向到QPlainTextEdit。我已经能够通过遵循this线程实现这一点。但是，我在理解实际代码时遇到了一些问题：

import logging
import sys

from PyQt5.QtCore import pyqtSignal, QObject
from PyQt5 import QtWidgets


class Handler(QObject, logging.Handler):
    new_record = pyqtSignal(object)

    def __init__(self):
        super().__init__()
        super(logging.Handler).__init__()

    def emit(self, record):
        msg = self.format(record)
        self.new_record.emit(msg)


class Formatter(logging.Formatter):
    def formatException(self, ei):
        result = super(Formatter, self).formatException(ei)
        return result

    def format(self, record):
        s = super(Formatter, self).format(record)
        if record.exc_text:
            s = s.replace('\n', '')
        return s


class MyTextBox(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()

        container = QtWidgets.QGroupBox()
        layout = QtWidgets.QVBoxLayout()

        self.text_box = QtWidgets.QPlainTextEdit()
        self.text_box.setReadOnly(True)
        layout.addWidget(self.text_box)

        self.btn = QtWidgets.QPushButton("Click me")
        layout.addWidget(self.btn)

        container.setLayout(layout)

        self.setCentralWidget(container)

        handler = Handler()
        logging.getLogger().addHandler(handler)
        logging.getLogger().setLevel(logging.INFO)
        handler.new_record.connect(self.text_box.appendPlainText)

        self.btn.clicked.connect(self.heClickedMe)

    def heClickedMe(self):
        logging.debug('damn, a bug')
        logging.info('something to remember')
        logging.warning('that\'s not right')
        logging.error('foobar')


app = QtWidgets.QApplication(sys.argv)
dlg = MyTextBox()
dlg.show()
sys.exit(app.exec_())

所以我很难理解Handler类中的"emit“方法。例如，"emit“方法是logging.Handler还是QObject？什么时候调用"emit“？

Answer 1

1. is“发出”logging.Handler或QObject?:的方法以了解使用文档时必须使用的类的方法，并且清楚地表明emit是have的一个方法

使用debug、info、warning和error方法时会在内部调用

1. When "emit“吗?示例：此方法在内部调用。