Question

我的问题是指问题How to capture output of Python's interpreter and show in a Text widget?的已接受答案，其中显示了如何将标准输出重定向到QTextEdit。

作者Ferdinand Beyer定义了一个类 EmittingStream ：

from PyQt4 import QtCore

class EmittingStream(QtCore.QObject):

    textWritten = QtCore.pyqtSignal(str)

    def write(self, text):
        self.textWritten.emit(str(text))

他使用这样的类：

# Within your main window class...

def __init__(self, parent=None, **kwargs):
    # ...

    # Install the custom output stream
    sys.stdout = EmittingStream(textWritten=self.normalOutputWritten)

def __del__(self):
    # Restore sys.stdout
    sys.stdout = sys.__stdout__

def normalOutputWritten(self, text):
    """Append text to the QTextEdit."""
    # Maybe QTextEdit.append() works as well, but this is how I do it:
    cursor = self.textEdit.textCursor()
    cursor.movePosition(QtGui.QTextCursor.End)
    cursor.insertText(text)
    self.textEdit.setTextCursor(cursor)
    self.textEdit.ensureCursorVisible()

我不理解实例化 EmittingStream 类的行。看起来好像关键字参数 textWritten = self.normalOutputWritten 将 textWritten -signal连接到 normalOutputWritten -slot，但我不明白为什么这很有效。

Answer 1

此功能为documented here：

也可以通过将插槽作为关键字来连接信号创建时对应于信号名称的参数对象，或使用QObject的pyqtConfigure（）方法。例如以下三个片段是等效的：

act = QtGui.QAction("Action", self)
act.triggered.connect(self.on_triggered)

act = QtGui.QAction("Action", self, triggered=self.on_triggered)

act = QtGui.QAction("Action", self)
act.pyqtConfigure(triggered=self.on_triggered)

理解一段python代码

1 个答案: