Question

我目前正在使用qt designer处理GUI。我想知道如何在GUI上打印字符串，就像记录器窗口一样。我正在使用pyqt5。

Answer 1

如果您使用Python logging模块可以轻松创建自定义日志记录处理程序，将日志消息传递到QPlainTextEdit实例（如Christopher所述）。

为此，您首先将logging.Handler子类化。在此__init__中，我们创建了包含日志的QPlainTextEdit。这里的关键位是句柄将通过emit()函数接收消息。因此，我们重载此函数并将消息文本传递到QPlainTextEdit。

import logging

class QPlainTextEditLogger(logging.Handler):
    def __init__(self, parent):
        super(Logger, self).__init__()

        self.widget = QPlainTextEdit(parent)
        self.widget.setReadOnly(True)

    def emit(self, record):
        msg = self.format(record)
        self.widget.textCursor().appendPlainText(msg)

    def write(self, m):
        pass

从此类创建一个对象，将其传递给QPlainTextEdit的父对象（例如主窗口或布局）。然后，您可以为当前记录器添加此处理程序。

# Set up logging to use your widget as a handler
log_handler = QPlainTextEditLogger(<parent widget>)
logging.getLogger().addHandler(log_handler)

Answer 2

以下是基于mfitzp's answer的完整工作示例：

<img src="~/Content/images/login-logo.png" width="{{image.width}}" height="{{image.size}}"/>
<div class="right-wrapper">
  <h3 class="right-head">Appearance <img src="~/Content/images/info-icon.png"></h3>
  <div ng-if="isImage">
      <div ng-class="form-group">
          size
          <input class="form-control" type="textbox" ng-model="image.size" />
      </div>
      <div ng-class="form-group">
          width
          <input class="form-control" type="textbox" ng-model="image.width" />
      </div>
  </div>
</div>

Answer 3

改编自Todd Vanyo的PyQt5示例：

import sys
from PyQt5 import QtWidgets
import logging

# Uncomment below for terminal log messages
# logging.basicConfig(level=logging.DEBUG, format=' %(asctime)s - %(name)s - %(levelname)s - %(message)s')

class QTextEditLogger(logging.Handler):
    def __init__(self, parent):
        super().__init__()
        self.widget = QtWidgets.QPlainTextEdit(parent)
        self.widget.setReadOnly(True)

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


class MyDialog(QtWidgets.QDialog, QtWidgets.QPlainTextEdit):
    def __init__(self, parent=None):
        super().__init__(parent)

        logTextBox = QTextEditLogger(self)
        # You can format what is printed to text box
        logTextBox.setFormatter(logging.Formatter('%(asctime)s - %(levelname)s - %(message)s'))
        logging.getLogger().addHandler(logTextBox)
        # You can control the logging level
        logging.getLogger().setLevel(logging.DEBUG)

        self._button = QtWidgets.QPushButton(self)
        self._button.setText('Test Me')

        layout = QtWidgets.QVBoxLayout()
        # Add the new logging box widget to the layout
        layout.addWidget(logTextBox.widget)
        layout.addWidget(self._button)
        self.setLayout(layout)

        # Connect signal to slot
        self._button.clicked.connect(self.test)

    def test(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 = MyDialog()
dlg.show()
dlg.raise_()
sys.exit(app.exec_())

Answer 4

线程安全版本

class QTextEditLogger(logging.Handler, QtCore.QObject):
    appendPlainText = QtCore.pyqtSignal(str)

def __init__(self, parent):
    super().__init__()
    QtCore.QObject.__init__(self)
    self.widget = QtWidgets.QPlainTextEdit(parent)
    self.widget.setReadOnly(True)
    self.appendPlainText.connect(self.widget.appendPlainText)

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

用法

    logTextBox = QTextEditLogger(self)

    # log to text box
    logTextBox.setFormatter(
        logging.Formatter(
            '%(asctime)s %(levelname)s %(module)s %(funcName)s %(message)s'))
    logging.getLogger().addHandler(logTextBox)
    logging.getLogger().setLevel(logging.DEBUG)

    # log to file
    fh = logging.FileHandler('my-log.log')
    fh.setLevel(logging.DEBUG)
    fh.setFormatter(
        logging.Formatter(
            '%(asctime)s %(levelname)s %(module)s %(funcName)s %(message)s'))
    logging.getLogger().addHandler(fh)

Answer 5

听起来你想要将QPlainTextEdit小部件设置为只读。

考虑将背景颜色更改为灰色，以便为用户提供不可编辑的提示。如果您希望它可滚动或文本可选，也由您决定。

This answer可以让你开始子类化QPlainTextEdit来滚动输出，保存到文件，等等。

Answer 6

在单线程情况下，Alex的回答应该可以，但是，如果您登录另一个线程（QThread），则会收到警告。

QObject::connect: Cannot queue arguments of type 'QTextCursor'
(Make sure 'QTextCursor' is registered using qRegisterMetaType().)

因为您正在从主线程以外的其他线程修改GUI（self.widget.appendPlainText(msg)），而不使用Signal / Slot。

这是我的解决方法：

# my_logger.py

import logging
from PyQt5.QtCore import pyqtSignal, QObject


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

    def __init__(self, parent):
        super().__init__(parent)
        super(logging.Handler).__init__()
        formatter = Formatter('%(asctime)s|%(levelname)s|%(message)s|', '%d/%m/%Y %H:%M:%S')
        self.setFormatter(formatter)

    def emit(self, record):
        msg = self.format(record)
        self.new_record.emit(msg) # <---- emit signal here

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

   # gui.py

   ... # GUI code
   ...
   def setup_logger(self)
        handler = Handler(self)
        log_text_box = QPlainTextEdit(self)
        self.main_layout.addWidget(log_text_box)
        logging.getLogger().addHandler(handler)
        logging.getLogger().setLevel(logging.INFO)
        handler.new_record.connect(log_text_box.appendPlainText) # <---- connect QPlainTextEdit.appendPlainText slot
   ...

在pyqt中显示日志的最佳方法？

6 个答案:

线程安全版本

用法