= Adding tab-completion to a QLineEdit =

On the `#pyqt` IRC channel on [[http://www.freenode.net|Freenode]], `sonic` asked how to handle key events for a QLineEdit widget to enable tab-completion.

The following code shows how to subclass QLineEdit and reimplement the `keyPressEvent()` method. The tab-completion code isn't ideal - you should probably consider using a QCompleter object to handle the process of completing an incomplete piece of text.

{{{
#!python
import sys
from PyQt4.QtCore import Qt
from PyQt4.QtGui import QApplication, QLineEdit

class LineEdit(QLineEdit):

    completion_items = [
        u"hello",
        u"world"
        ]

    def __init__(self, parent = None):
    
        QLineEdit.__init__(self, parent)
    
    def keyPressEvent(self, event):
    
        if event.key() == Qt.Key_Tab:
            for item in self.completion_items:
                if item.startswith(self.text()):
                    self.setText(item)
                    break
            
            event.accept()
        else:
            QLineEdit.keyPressEvent(self, event)


if __name__ == "__main__":

    app = QApplication(sys.argv)
    window = LineEdit()
    window.show()
    sys.exit(app.exec_())
}}}