PyQt4 : making certain text on QTextEdit uneditable

Question

Is there any way I can make certain text on QTextEdit permanent. Applications like cmd.exe where the current user directory is displayed and the rest of the screen is up for input. I tried inserting a QLabel but unable to do so, here's my code, I am currently taking user input through a separate line edit.

UPDATE I had a look at Ipython QtConsole where the line number is displayed constantly, how can I do that, I am looking in the source but if anyone who already knows it, please do tell. Here is the QtConsole for ipython notebook, I am trying to replicate this.

import os
import sys
import PyQt4
import PyQt4.QtCore
from PyQt4.QtGui import *


def main():
    app = QApplication(sys.argv)
    w = MyWindow()
    w.show()
    sys.exit(app.exec_())


class MyWindow(QWidget):
    def __init__(self, *args):
        QWidget.__init__(self, *args)

        # create objects
        label = QLabel(self.tr("Enter command and press Return"))
        self.le = QLineEdit()
        self.te = QTextEdit()
        self.lbl = QLabel(str(os.getcwd())+"> ")

        # layout
        layout = QVBoxLayout(self)
        layout.addWidget(label)
        layout.addWidget(self.le)
        layout.addWidget(self.te)
        self.setLayout(layout)

        # styling
        self.te.setReadOnly(True)

        # create connection
        self.mytext = str(self.le.text())
        self.connect(self.le, PyQt4.QtCore.SIGNAL("returnPressed(void)"),
                     self.display)

    def display(self):
        mytext = str(self.le.text())
        self.te.append(self.lbl +str(os.popen(mytext).read()))
        self.le.setText("")


if __name__ == "__main__":
    main()

Answer 1

A simple solution is to create a class that inherits from QTextEdit and overwrite and add the necessary attributes as shown below:

class TextEdit(QTextEdit):
    def __init__(self, *args, **kwargs):
        QTextEdit.__init__(self, *args, **kwargs)
        self.staticText = os.getcwd()
        self.counter = 1
        self.setReadOnly(True)

    def append(self, text):
        n_text = "{text} [{number}] > ".format(text=self.staticText, number=self.counter)
        self.counter += 1
        QTextEdit.append(self, n_text+text)

Complete Code:

import os
import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

class TextEdit(QTextEdit):
    def __init__(self, *args, **kwargs):
        QTextEdit.__init__(self, *args, **kwargs)
        self.staticText = os.getcwd()
        self.counter = 1
        self.setReadOnly(True)

    def append(self, text):
        n_text = "{text} [{number}] > ".format(text=self.staticText, number=self.counter)
        self.counter += 1
        QTextEdit.append(self, n_text+text)


class MyWindow(QWidget):
    def __init__(self, *args, **kwargs):
        QWidget.__init__(self, *args, **kwargs)
        label = QLabel(self.tr("Enter command and press Return"), self)
        self.le = QLineEdit(self)
        self.te = TextEdit(self)
        # layout
        layout = QVBoxLayout(self)
        layout.addWidget(label)
        layout.addWidget(self.le)
        layout.addWidget(self.te)
        self.setLayout(layout)
        self.connect(self.le, SIGNAL("returnPressed(void)"), self.display)
        # self.le.returnPressed.connect(self.display)

    def display(self):
        command = str(self.le.text())
        resp = str(os.popen(command).read())
        self.te.append(resp)
        self.le.clear()


def main():
    app = QApplication(sys.argv)
    w = MyWindow()
    w.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

---

To emulate QtConsole we must overwrite some methods of QTextEdit, catch some events, and verify that it does not eliminate the prefix as I show below:

import os
import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

class TextEdit(QTextEdit):
    def __init__(self, *args, **kwargs):
        QTextEdit.__init__(self, *args, **kwargs)
        self.staticText = os.getcwd()
        self.counter = 1
        self.prefix = ""
        self.callPrefix()
        self.setContextMenuPolicy(Qt.CustomContextMenu)
        self.customContextMenuRequested.connect(self.onCustomContextMenuRequest)

    def onCustomContextMenuRequest(self, point):
        menu = self.createStandardContextMenu()
        for action in menu.actions():
            if "Delete" in action.text():
                action.triggered.disconnect()
                menu.removeAction(action)
            elif "Cu&t" in action.text():
                action.triggered.disconnect()
                menu.removeAction(action)
            elif "Paste" in action.text():
                action.triggered.disconnect()

        act = menu.exec_(point)
        if act:
            if "Paste" in act.text():
                self.customPaste()


    def customPaste(self):
        self.moveCursor(QTextCursor.End)
        self.insertPlainText(QApplication.clipboard().text())
        self.moveCursor(QTextCursor.End)

    def clearCurrentLine(self):
        cs = self.textCursor()
        cs.movePosition(QTextCursor.StartOfLine)
        cs.movePosition(QTextCursor.EndOfLine)
        cs.select(QTextCursor.LineUnderCursor)
        text = cs.removeSelectedText()

    def isPrefix(self, text):
        return self.prefix == text

    def getCurrentLine(self):
        cs = self.textCursor()
        cs.movePosition(QTextCursor.StartOfLine)
        cs.movePosition(QTextCursor.EndOfLine)
        cs.select(QTextCursor.LineUnderCursor)
        text = cs.selectedText()
        return text

    def keyPressEvent(self, event):
        if event.key() == Qt.Key_Return:
            command = self.getCurrentLine()[len(self.prefix):]
            self.execute(command)
            self.callPrefix()
            return
        elif event.key() == Qt.Key_Backspace:
            if self.prefix == self.getCurrentLine():
                return
        elif event.matches(QKeySequence.Delete):
            return
        if event.matches(QKeySequence.Paste):
            self.customPaste()
            return
        elif self.textCursor().hasSelection():
            t = self.toPlainText()
            self.textCursor().clearSelection()
            QTextEdit.keyPressEvent(self, event)
            self.setPlainText(t)
            self.moveCursor(QTextCursor.End)
            return
        QTextEdit.keyPressEvent(self, event)

    def callPrefix(self):
        self.prefix = "{text} [{number}] >".format(text=self.staticText, number=self.counter)
        self.counter += 1
        self.append(self.prefix)

    def execute(self, command):
        resp = os.popen(command).read()
        self.append(resp)


class MyWindow(QWidget):
    def __init__(self, *args, **kwargs):
        QWidget.__init__(self, *args, **kwargs)
        label = QLabel(self.tr("Enter command and press Return"), self)
        self.te = TextEdit(self)
        # layout
        layout = QVBoxLayout(self)
        layout.addWidget(label)
        layout.addWidget(self.te)
        self.setLayout(layout)

def main():
    app = QApplication(sys.argv)
    w = MyWindow()
    w.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()