Signals and slots in PyQt5

Question

I have been trying to convert the following code to PyQt5. After changing QtGui.QTextEdit to QtWidgets.QTextEdit and making other small modifications, I am stuck at the line:

self.connect(self, QtCore.SIGNAL("activated(const QString&)"), self.changeCompletion)

in the MyDictionaryCompleter class.

The signal and slots functionality in PyQT5 appears to have been updated. How will I do this? Will there be any other problems?

This is the code:

from PyQt4 import QtGui, QtCore

class MyTextEdit(QtGui.QTextEdit):

    def __init__(self, *args):
        #*args to set parent
        QtGui.QLineEdit.__init__(self,*args)
        font=QtGui.QFont()
        font.setPointSize(12)
        self.setFont(font)
        self.completer = None

    def setCompleter(self, completer):
        if self.completer:
            self.disconnect(self.completer, 0, self, 0)
        if not completer:
            return

        completer.setWidget(self)
        completer.setCompletionMode(QtGui.QCompleter.PopupCompletion)
        completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        self.completer = completer
        self.completer.insertText.connect(self.insertCompletion)

    def insertCompletion(self, completion):
        tc = self.textCursor()
        extra = (len(completion) -
            len(self.completer.completionPrefix()))
        tc.movePosition(QtGui.QTextCursor.Left)
        tc.movePosition(QtGui.QTextCursor.EndOfWord)
        tc.insertText(completion[-extra:])
        self.setTextCursor(tc)

    def textUnderCursor(self):
        tc = self.textCursor()
        tc.select(QtGui.QTextCursor.WordUnderCursor)
        return tc.selectedText()

    def focusInEvent(self, event):
        if self.completer:
            self.completer.setWidget(self);
        QtGui.QTextEdit.focusInEvent(self, event)

    def keyPressEvent(self, event):
        if self.completer and self.completer.popup() and self.completer.popup().isVisible():
            if event.key() in (
            QtCore.Qt.Key_Enter,
            QtCore.Qt.Key_Return,
            QtCore.Qt.Key_Escape,
            QtCore.Qt.Key_Tab,
            QtCore.Qt.Key_Backtab):
                event.ignore()
                return
        ## has ctrl-Space been pressed??
        isShortcut = (event.modifiers() == QtCore.Qt.ControlModifier and\
                      event.key() == QtCore.Qt.Key_Space)
        ## modifier to complete suggestion inline ctrl-e
        inline = (event.modifiers() == QtCore.Qt.ControlModifier and \
                  event.key() == QtCore.Qt.Key_E)
        ## if inline completion has been chosen
        if inline:
            # set completion mode as inline
            self.completer.setCompletionMode(QtGui.QCompleter.InlineCompletion)
            completionPrefix = self.textUnderCursor()
            if (completionPrefix != self.completer.completionPrefix()):
                self.completer.setCompletionPrefix(completionPrefix)
            self.completer.complete()

            # set the current suggestion in the text box
            self.completer.insertText.emit(self.completer.currentCompletion())
            # reset the completion mode
            self.completer.setCompletionMode(QtGui.QCompleter.PopupCompletion)
            return
        if (not self.completer or not isShortcut):
            pass
            QtGui.QTextEdit.keyPressEvent(self, event)

        ctrlOrShift = event.modifiers() in (QtCore.Qt.ControlModifier ,\
                QtCore.Qt.ShiftModifier)
        if ctrlOrShift and event.text()== '':
            return
        eow = "~!@#$%^&*+{}|:\"<>?,./;'[]\\-=" #end of word

        hasModifier = ((event.modifiers() != QtCore.Qt.NoModifier) and\
                        not ctrlOrShift)

        completionPrefix = self.textUnderCursor()

        if not isShortcut :
            if self.completer.popup():
                self.completer.popup().hide()
            return

        self.completer.setCompletionPrefix(completionPrefix)
        popup = self.completer.popup()
        popup.setCurrentIndex(
            self.completer.completionModel().index(0,0))
        cr = self.cursorRect()
        cr.setWidth(self.completer.popup().sizeHintForColumn(0)
            + self.completer.popup().verticalScrollBar().sizeHint().width())
        self.completer.complete(cr) ## popup it up!




class MyDictionaryCompleter(QtGui.QCompleter):
    insertText = QtCore.pyqtSignal(str)

    def __init__(self, myKeywords=None,parent=None):

        myKeywords =['apple','aggresive','ball','bat','cat','cycle','dog','dumb',\
                     'elephant','engineer','food','file','good','great',\
                     'hippopotamus','hyper','india','ireland','just','just',\
                     'key','kid','lemon','lead','mute','magic',\
                     'news','newyork','orange','oval','parrot','patriot',\
                     'question','queue','right','rest','smile','simple',\
                     'tree','urban','very','wood','xylophone','yellow',\
                     'zebra']
        QtGui.QCompleter.__init__(self, myKeywords, parent)
        self.connect(self,
            QtCore.SIGNAL("activated(const QString&)"), self.changeCompletion)

    def changeCompletion(self, completion):
        if completion.find("(") != -1:
            completion = completion[:completion.find("(")]
        print(completion)
        self.insertText.emit(completion)

if __name__ == "__main__":

    app = QtGui.QApplication([])
    completer = MyDictionaryCompleter()
    te = MyTextEdit()
    te.setCompleter(completer)
    te.show()
    app.exec_()

Answer 1

The following are the main changes:

• You must use the new syntax, change self.connect(self, QtCore.SIGNAL("activated(const QString&)"), self.changeCompletion) to self.activated.connect(self.changeCompletion) .

• QCompleter and QTextEdit are part of the QtWidgets submodule.

from PyQt5 import QtCore, QtGui, QtWidgets


class MyTextEdit(QtWidgets.QTextEdit):
    def __init__(self, parent=None):
        super(MyTextEdit, self).__init__(parent)
        font = QtGui.QFont()
        font.setPointSize(12)
        self.setFont(font)
        self.completer = None

    def setCompleter(self, completer):
        if self.completer:
            self.disconnect(self.completer, 0, self, 0)
        if not completer:
            return

        completer.setWidget(self)
        completer.setCompletionMode(QtWidgets.QCompleter.PopupCompletion)
        completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        self.completer = completer
        self.completer.insertText.connect(self.insertCompletion)

    def insertCompletion(self, completion):
        tc = self.textCursor()
        extra = len(completion) - len(self.completer.completionPrefix())
        tc.movePosition(QtGui.QTextCursor.Left)
        tc.movePosition(QtGui.QTextCursor.EndOfWord)
        tc.insertText(completion[-extra:])
        self.setTextCursor(tc)

    def textUnderCursor(self):
        tc = self.textCursor()
        tc.select(QtGui.QTextCursor.WordUnderCursor)
        return tc.selectedText()

    def focusInEvent(self, event):
        if self.completer:
            self.completer.setWidget(self)
        super(MyTextEdit, self).focusInEvent(event)

    def keyPressEvent(self, event):
        if (
            self.completer
            and self.completer.popup()
            and self.completer.popup().isVisible()
        ):
            if event.key() in (
                QtCore.Qt.Key_Enter,
                QtCore.Qt.Key_Return,
                QtCore.Qt.Key_Escape,
                QtCore.Qt.Key_Tab,
                QtCore.Qt.Key_Backtab,
            ):
                event.ignore()
                return
        ## has ctrl-Space been pressed??
        isShortcut = (
            event.modifiers() == QtCore.Qt.ControlModifier
            and event.key() == QtCore.Qt.Key_Space
        )
        ## modifier to complete suggestion inline ctrl-e
        inline = (
            event.modifiers() == QtCore.Qt.ControlModifier
            and event.key() == QtCore.Qt.Key_E
        )
        ## if inline completion has been chosen
        if inline:
            # set completion mode as inline
            self.completer.setCompletionMode(
                QtWidgets.QCompleter.InlineCompletion
            )
            completionPrefix = self.textUnderCursor()
            if completionPrefix != self.completer.completionPrefix():
                self.completer.setCompletionPrefix(completionPrefix)
            self.completer.complete()

            # set the current suggestion in the text box
            self.completer.insertText.emit(self.completer.currentCompletion())
            # reset the completion mode
            self.completer.setCompletionMode(
                QtWidgets.QCompleter.PopupCompletion
            )
            return
        if not self.completer or not isShortcut:
            pass
            super(MyTextEdit, self).keyPressEvent(event)

        ctrlOrShift = event.modifiers() in (
            QtCore.Qt.ControlModifier,
            QtCore.Qt.ShiftModifier,
        )
        if ctrlOrShift and event.text() == "":
            return
        eow = "~!@#$%^&*+{}|:\"<>?,./;'[]\\-="  # end of word

        hasModifier = (
            event.modifiers() != QtCore.Qt.NoModifier
        ) and not ctrlOrShift

        completionPrefix = self.textUnderCursor()

        if not isShortcut:
            if self.completer.popup():
                self.completer.popup().hide()
            return

        self.completer.setCompletionPrefix(completionPrefix)
        popup = self.completer.popup()
        popup.setCurrentIndex(self.completer.completionModel().index(0, 0))
        cr = self.cursorRect()
        cr.setWidth(
            self.completer.popup().sizeHintForColumn(0)
            + self.completer.popup().verticalScrollBar().sizeHint().width()
        )
        self.completer.complete(cr)  ## popup it up!


class MyDictionaryCompleter(QtWidgets.QCompleter):
    insertText = QtCore.pyqtSignal(str)

    def __init__(self, parent=None):

        myKeywords =['apple','aggresive','ball','bat','cat','cycle','dog','dumb',\
                     'elephant','engineer','food','file','good','great',\
                     'hippopotamus','hyper','india','ireland','just','just',\
                     'key','kid','lemon','lead','mute','magic',\
                     'news','newyork','orange','oval','parrot','patriot',\
                     'question','queue','right','rest','smile','simple',\
                     'tree','urban','very','wood','xylophone','yellow',\
                     'zebra']
        super(MyDictionaryCompleter, self).__init__(myKeywords, parent)
        self.activated.connect(self.changeCompletion)

    @QtCore.pyqtSlot(str)
    def changeCompletion(self, completion):
        print(completion)
        if completion.find("(") != -1:
            completion = completion[: completion.find("(")]
        print(completion)
        self.insertText.emit(completion)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    completer = MyDictionaryCompleter()
    te = MyTextEdit()
    te.setCompleter(completer)
    te.show()
    sys.exit(app.exec_())