extended_combo_box.py

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#!/usr/bin/env python

# Copyright (c) 2011, Dorian Scholz, TU Darmstadt
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
#   * Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#   * Redistributions in binary form must reproduce the above
#     copyright notice, this list of conditions and the following
#     disclaimer in the documentation and/or other materials provided
#     with the distribution.
#   * Neither the name of the TU Darmstadt nor the names of its
#     contributors may be used to endorse or promote products derived
#     from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

try:
    from python_qt_binding.QtCore import QSortFilterProxyModel  # Qt 5
except ImportError:
    from python_qt_binding.QtGui import QSortFilterProxyModel  # Qt 4
from python_qt_binding.QtCore import Qt, Signal, Slot
from python_qt_binding.QtWidgets import QComboBox, QCompleter


class ExtendedComboBox(QComboBox):
    setItems = Signal(list)

    def __init__(self, parent=None):
        super(ExtendedComboBox, self).__init__(parent)

        self.setFocusPolicy(Qt.StrongFocus)
        self.setEditable(True)

        # add a filter model to filter matching items
        self.filter_model = QSortFilterProxyModel(self)
        self.filter_model.setFilterCaseSensitivity(Qt.CaseInsensitive)
        self.filter_model.setSourceModel(self.model())

        # add a completer, which uses the filter model
        self.completer = QCompleter(self.filter_model, self)
        # always show all (filtered) completions
        self.completer.setCompletionMode(QCompleter.UnfilteredPopupCompletion)
        self.setCompleter(self.completer)

        # connect signals
        self.lineEdit().textEdited[str].connect(self.filter_model.setFilterFixedString)
        self.completer.activated.connect(self.on_completer_activated)
        self.setItems.connect(self.onSetItems)

    # on selection of an item from the completer, select the corresponding item from combobox
    def on_completer_activated(self, text):
        if text:
            index = self.findText(text)
            self.setCurrentIndex(index)

    # on model change, update the models of the filter and completer as well
    def setModel(self, model):
        super(ExtendedComboBox, self).setModel(model)
        self.filter_model.setSourceModel(model)
        self.completer.setModel(self.filter_model)

    # on model column change, update the model column of the filter and completer as well
    def setModelColumn(self, column):
        self.completer.setCompletionColumn(column)
        self.filter_model.setFilterKeyColumn(column)
        super(ExtendedComboBox, self).setModelColumn(column)

    @Slot(list)
    def onSetItems(self, items):
        self.clear()
        self.addItems(items)


if __name__ == "__main__":
    import sys
    from python_qt_binding.QtGui import QApplication

    app = QApplication(sys.argv)

    string_list = ['hola muchachos', 'adios amigos', 'hello world', 'good bye']

    combo = ExtendedComboBox()

    # either fill the standard model of the combobox
    combo.addItems(string_list)

    # or use another model
    # combo.setModel(QStringListModel(string_list))

    combo.resize(300, 40)
    combo.show()

    sys.exit(app.exec_())