Tuesday, 3 August 2010

QTextEdit with autocompletion using pyqt

Problem - I wanted a text-edit which would help enter long words.

Solution - I have converted the C++ example code into python, and post it here to for all to see.

NB - The code assumes your dictionary is located at /usr/share/dict/words.

from PyQt4 import QtGui, QtCore

STARTTEXT = ('This TextEdit provides autocompletions for words that have ' +
'more than 3 characters.\nYou can trigger autocompletion using %s\n\n'''% (
QtGui.QKeySequence("Ctrl+E").toString(QtGui.QKeySequence.NativeText)))

class DictionaryCompleter(QtGui.QCompleter):
    def __init__(self, parent=None):
        words = []
        try:
            f = open("/usr/share/dict/words","r")
            for word in f:
                words.append(word.strip())
            f.close()
        except IOError:
            print "dictionary not in anticipated location"
        QtGui.QCompleter.__init__(self, words, parent)

class CompletionTextEdit(QtGui.QTextEdit):
    def __init__(self, parent=None):
        super(CompletionTextEdit, self).__init__(parent)
        self.setMinimumWidth(400)
        self.setPlainText(STARTTEXT)
        self.completer = None
        self.moveCursor(QtGui.QTextCursor.End)

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

    def insertCompletion(self, completion):
        tc = self.textCursor()
        extra = (completion.length() -
            self.completer.completionPrefix().length())
        tc.movePosition(QtGui.QTextCursor.Left)
        tc.movePosition(QtGui.QTextCursor.EndOfWord)
        tc.insertText(completion.right(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().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-E been pressed??
        isShortcut = (event.modifiers() == QtCore.Qt.ControlModifier and
                      event.key() == QtCore.Qt.Key_E)
        if (not self.completer or not isShortcut):
            QtGui.QTextEdit.keyPressEvent(self, event)

        ## ctrl or shift key on it's own??
        ctrlOrShift = event.modifiers() in (QtCore.Qt.ControlModifier ,
                QtCore.Qt.ShiftModifier)
        if ctrlOrShift and event.text().isEmpty():
            # ctrl or shift key on it's own
            return

        eow = QtCore.QString("~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-=") #end of word

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

        completionPrefix = self.textUnderCursor()

        if (not isShortcut and (hasModifier or event.text().isEmpty() or
        completionPrefix.length() < 3 or
        eow.contains(event.text().right(1)))):
            self.completer.popup().hide()
            return

        if (completionPrefix != self.completer.completionPrefix()):
            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!

if __name__ == "__main__":

    app = QtGui.QApplication([])
    completer = DictionaryCompleter()
    te = CompletionTextEdit()
    te.setCompleter(completer)
    te.show()
    app.exec_()

7 comments:

ZakW said...

Thanks for sharing! Made a handful of minor tweaks for Python3, to use Python strings instead of QStrings, and I was away. Now if only I could find a simple way to match anywhere rather than just prefixes...

minn said...

Thanks a lot!
I just working on a editor. It's very useful for me.

Murphy said...

Yeah, thanks for sharing!

Tcll said...
This comment has been removed by the author.
Tcll said...

is there a QsciScintilla version of this??
(one that ACTUALLY updates themenu like this)

تسنيم حمد النيل said...

than you so mush for your code it go on help ma alot

astrofrog said...

Thanks, this is great! Would it be ok to use this in a BSD-licensed project?