maggie maggie - 5 months ago 57
Python Question

How to format the list items of QCompleter's popup list properly?

I want to investigate how to make a small user interface in which a user can type some letters and gets some suggestions based on a given data source (list here) which makes searches easier. For this purpose i am using Qt's

QCompleter
class.

In the matching elements the typed letters shall be highlighted with HTML like the example in the code below:
Au<b>st</b>ria
.
Finally i merged some SO answers (see How to make item view render rich (html) text in Qt) and tutorials to a small standalone module:

from PySide import QtCore, QtGui

class HTMLDelegate(QtGui.QStyledItemDelegate):
""" From: http://stackoverflow.com/a/5443112/1504082 """

def paint(self, painter, option, index):
options = QtGui.QStyleOptionViewItemV4(option)
self.initStyleOption(options, index)
if options.widget is None:
style = QtGui.QApplication.style()
else:
style = options.widget.style()

doc = QtGui.QTextDocument()
doc.setHtml(options.text)
doc.setTextWidth(option.rect.width())

options.text = ""
style.drawControl(QtGui.QStyle.CE_ItemViewItem, options, painter)

ctx = QtGui.QAbstractTextDocumentLayout.PaintContext()

# Highlighting text if item is selected
# if options.state & QtGui.QStyle.State_Selected:
# ctx.palette.setColor(QtGui.QPalette.Text,
# options.palette.color(QtGui.QPalette.Active,
# QtGui.QPalette.HighlightedText))

textRect = style.subElementRect(QtGui.QStyle.SE_ItemViewItemText,
options)
painter.save()
painter.translate(textRect.topLeft())
painter.setClipRect(textRect.translated(-textRect.topLeft()))
doc.documentLayout().draw(painter, ctx)
painter.restore()

def sizeHint(self, option, index):
options = QtGui.QStyleOptionViewItemV4(option)
self.initStyleOption(options, index)
doc = QtGui.QTextDocument()
doc.setHtml(options.text)
doc.setTextWidth(options.rect.width())
return QtCore.QSize(doc.size().width(), doc.size().height())


class CustomQCompleter(QtGui.QCompleter):
""" Implement "contains" filter mode as the filter mode "contains" is not
available in Qt < 5.2
From: http://stackoverflow.com/a/7767999/1504082 """

def __init__(self, parent=None):
super(CustomQCompleter, self).__init__(parent)
self.local_completion_prefix = ""
self.source_model = None
self.delegate = HTMLDelegate()

def setModel(self, model):
self.source_model = model
super(CustomQCompleter, self).setModel(self.source_model)

def updateModel(self):
local_completion_prefix = self.local_completion_prefix

# see: http://doc.qt.io/qt-4.8/model-view-programming.html#proxy-models
class InnerProxyModel(QtGui.QSortFilterProxyModel):
def filterAcceptsRow(self, sourceRow, sourceParent):
# model index mapping by row, 1d model => column is always 0
index = self.sourceModel().index(sourceRow, 0, sourceParent)
source_data = self.sourceModel().data(index, QtCore.Qt.DisplayRole)
# performs case insensitive matching
# return True if item shall stay in th returned filtered data
# return False to reject an item
return local_completion_prefix.lower() in source_data.lower()

proxy_model = InnerProxyModel()
proxy_model.setSourceModel(self.source_model)
super(CustomQCompleter, self).setModel(proxy_model)
# @todo: Why to be set here again?
self.popup().setItemDelegate(self.delegate)

def splitPath(self, path):
self.local_completion_prefix = path
self.updateModel()
return ""


class AutoCompleteEdit(QtGui.QLineEdit):
""" Basically from:
http://doc.qt.io/qt-5/qtwidgets-tools-customcompleter-example.html
"""

def __init__(self, list_data, separator=' ', addSpaceAfterCompleting=True):
super(AutoCompleteEdit, self).__init__()
# settings
self._separator = separator
self._addSpaceAfterCompleting = addSpaceAfterCompleting
# completer
self._completer = CustomQCompleter(self)
self._completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
self._completer.setCompletionMode(QtGui.QCompleter.PopupCompletion)

self.model = QtGui.QStringListModel(list_data)
self._completer.setModel(self.model)

# connect the completer to the line edit
self._completer.setWidget(self)
# trigger insertion of the selected completion when its activated
self.connect(self._completer,
QtCore.SIGNAL('activated(QString)'),
self._insertCompletion)

self._ignored_keys = [QtCore.Qt.Key_Enter,
QtCore.Qt.Key_Return,
QtCore.Qt.Key_Escape,
QtCore.Qt.Key_Tab]

def _insertCompletion(self, completion):
"""
This is the event handler for the QCompleter.activated(QString) signal,
it is called when the user selects an item in the completer popup.
It will remove the already typed string with the one of the completion.
"""
stripped_text = self.text()[:-len(self._completer.completionPrefix())]

extra_text = completion # [-extra:]
if self._addSpaceAfterCompleting:
extra_text += ' '
self.setText(stripped_text + extra_text)

def textUnderCursor(self):
text = self.text()
textUnderCursor = ''
i = self.cursorPosition() - 1
while i >= 0 and text[i] != self._separator:
textUnderCursor = text[i] + textUnderCursor
i -= 1
return textUnderCursor

def keyPressEvent(self, event):
if self._completer.popup().isVisible():
if event.key() in self._ignored_keys:
event.ignore()
return
super(AutoCompleteEdit, self).keyPressEvent(event)
completionPrefix = self.textUnderCursor()
if completionPrefix != self._completer.completionPrefix():
self._updateCompleterPopupItems(completionPrefix)
if len(event.text()) > 0 and len(completionPrefix) > 0:
self._completer.complete()
if len(completionPrefix) == 0:
self._completer.popup().hide()

def _updateCompleterPopupItems(self, completionPrefix):
"""
Filters the completer's popup items to only show items
with the given prefix.
"""
self._completer.setCompletionPrefix(completionPrefix)
# self._completer.popup().setCurrentIndex(
# self._completer.completionModel().index(0, 0))


if __name__ == '__main__':
def demo():
import sys
app = QtGui.QApplication(sys.argv)
values = ['Germany',
'Au<b>st</b>ria',
'Switzerland',
'Hungary',
'The United Kingdom of Great Britain and Northern Ireland']
editor = AutoCompleteEdit(values)
window = QtGui.QWidget()
hbox = QtGui.QHBoxLayout()
hbox.addWidget(editor)
window.setLayout(hbox)
window.show()

sys.exit(app.exec_())

demo()


My problem is the suggestion of user Timo in the answer http://stackoverflow.com/a/5443112/1504082:


After line: 'doc.setHtml(options.text)', you need to set also doc.setTextWidth(option.rect.width()), otherwise the delegate wont render longer content correctly in respect to target drawing area. For example does not wrap words in QListView.


So i did this to avoid cropping of long text in the completer's popup. But i get the following output:
Where does this vertical margin come from?

Where does this additional vertical margin come from?

I investigated this a bit and i see that the
sizeHint
method of
HTMLDelegate
is sometimes called with an
options
parameter which contains a rectangle with attributes
(0, 0, 0, 0)
. And the display behaviour finally changes after the call of
doc.setTextWidth(options.rect.width())
. But i couldnt finally find out who calls it with this parameter and how i could properly fix this.

Can somebody explain where this comes from and how i can fix this porperly?

Answer

Finally i found another way to realize it using the idea of http://stackoverflow.com/a/8036666/1504082. Its much more forward for me without all this custom drawing things which i dont understand yet :)

from PySide import QtCore, QtGui


class TaskDelegate(QtGui.QItemDelegate):
    # based on http://stackoverflow.com/a/8036666/1504082
    # http://doc.qt.nokia.com/4.7/qitemdelegate.html#drawDisplay
    # http://doc.qt.nokia.com/4.7/qwidget.html#render
    margin_x = 5
    margin_y = 3

    def drawDisplay(self, painter, option, rect, text):
        label = self.make_label(option, text)
        # calculate render anchor point
        point = rect.topLeft()
        point.setX(point.x() + self.margin_x)
        point.setY(point.y() + self.margin_y)

        label.render(painter, point, renderFlags=QtGui.QWidget.DrawChildren)

    def sizeHint(self, option, index):
        # get text using model and index
        text = index.model().data(index)
        label = self.make_label(option, text)
        return QtCore.QSize(label.width(), label.height() + self.margin_y)

    def make_label(self, option, text):
        label = QtGui.QLabel(text)

        if option.state & QtGui.QStyle.State_Selected:
            p = option.palette
            p.setColor(QtGui.QPalette.WindowText,
                       p.color(QtGui.QPalette.Active,
                               QtGui.QPalette.HighlightedText)
                       )

            label.setPalette(p)

        label.setStyleSheet("border: 1px dotted black")

        # adjust width according to widget's target width
        label.setMinimumWidth(self.target_width - (2 * self.margin_x))
        label.setMaximumWidth(self.target_width - self.margin_x)
        label.setWordWrap(True)
        label.adjustSize()
        return label


class CustomQCompleter(QtGui.QCompleter):
    """ Implement "contains" filter mode as the filter mode "contains" is not
    available in Qt < 5.2
    From: http://stackoverflow.com/a/7767999/1504082 """

    def __init__(self, parent=None):
        super(CustomQCompleter, self).__init__(parent)
        self.local_completion_prefix = ""
        self.source_model = None
        self.delegate = TaskDelegate()
        # widget not set yet
        # self.delegate.target_width = self.widget().width()

    def setModel(self, model):
        self.source_model = model
        super(CustomQCompleter, self).setModel(self.source_model)

    def updateModel(self):
        local_completion_prefix = self.local_completion_prefix

        # see: http://doc.qt.io/qt-4.8/model-view-programming.html#proxy-models
        class InnerProxyModel(QtGui.QSortFilterProxyModel):
            def filterAcceptsRow(self, sourceRow, sourceParent):
                # model index mapping by row, 1d model => column is always 0
                index = self.sourceModel().index(sourceRow, 0, sourceParent)
                source_data = self.sourceModel().data(index, QtCore.Qt.DisplayRole)
                # performs case insensitive matching
                # return True if item shall stay in th returned filtered data
                # return False to reject an item
                return local_completion_prefix.lower() in source_data.lower()

        proxy_model = InnerProxyModel()
        proxy_model.setSourceModel(self.source_model)
        super(CustomQCompleter, self).setModel(proxy_model)
        # @todo: Why to be set here again?
        # -> rescale popup list items to widget width
        self.delegate.target_width = self.widget().width()
        self.popup().setItemDelegate(self.delegate)

    def splitPath(self, path):
        self.local_completion_prefix = path
        self.updateModel()
        return ""


class AutoCompleteEdit(QtGui.QLineEdit):
    """ Basically from:
    http://doc.qt.io/qt-5/qtwidgets-tools-customcompleter-example.html
    """

    def __init__(self, list_data, separator=' ', addSpaceAfterCompleting=True):
        super(AutoCompleteEdit, self).__init__()
        # settings
        self._separator = separator
        self._addSpaceAfterCompleting = addSpaceAfterCompleting
        # completer
        self._completer = CustomQCompleter(self)
        self._completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        self._completer.setCompletionMode(QtGui.QCompleter.PopupCompletion)

        self.model = QtGui.QStringListModel(list_data)
        self._completer.setModel(self.model)

        # connect the completer to the line edit
        self._completer.setWidget(self)
        # trigger insertion of the selected completion when its activated
        self.connect(self._completer,
                     QtCore.SIGNAL('activated(QString)'),
                     self._insertCompletion)

        self._ignored_keys = [QtCore.Qt.Key_Enter,
                              QtCore.Qt.Key_Return,
                              QtCore.Qt.Key_Escape,
                              QtCore.Qt.Key_Tab]

    def _insertCompletion(self, completion):
        """
        This is the event handler for the QCompleter.activated(QString) signal,
        it is called when the user selects an item in the completer popup.
        It will remove the already typed string with the one of the completion.
        """
        stripped_text = self.text()[:-len(self._completer.completionPrefix())]

        extra_text = completion  # [-extra:]
        if self._addSpaceAfterCompleting:
            extra_text += ' '
        self.setText(stripped_text + extra_text)

    def textUnderCursor(self):
        text = self.text()
        textUnderCursor = ''
        i = self.cursorPosition() - 1
        while i >= 0 and text[i] != self._separator:
            textUnderCursor = text[i] + textUnderCursor
            i -= 1
        return textUnderCursor

    def keyPressEvent(self, event):
        if self._completer.popup().isVisible():
            if event.key() in self._ignored_keys:
                event.ignore()
                return
        super(AutoCompleteEdit, self).keyPressEvent(event)
        completionPrefix = self.textUnderCursor()
        if completionPrefix != self._completer.completionPrefix():
            self._updateCompleterPopupItems(completionPrefix)
        if len(event.text()) > 0 and len(completionPrefix) > 0:
            self._completer.complete()
        if len(completionPrefix) == 0:
            self._completer.popup().hide()

    def _updateCompleterPopupItems(self, completionPrefix):
        """
        Filters the completer's popup items to only show items
        with the given prefix.
        """
        self._completer.setCompletionPrefix(completionPrefix)
        # self._completer.popup().setCurrentIndex(
        #     self._completer.completionModel().index(0, 0))


if __name__ == '__main__':
    def demo():
        import sys
        app = QtGui.QApplication(sys.argv)
        values = ['Germany',
                  'Au<b>st</b>ria',
                  'Switzerland',
                  'Hungary',
                  'The United Kingdom of Great Britain and Northern Ireland',
                  'USA']
        editor = AutoCompleteEdit(values)
        window = QtGui.QWidget()
        hbox = QtGui.QHBoxLayout()
        hbox.addWidget(editor)
        window.setLayout(hbox)
        window.show()

        sys.exit(app.exec_())

    demo()
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