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PyQt QComboBox

last modified July 9, 2020

PyQt QComboBox tutorial shows how to work with QComboBox widget.

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PyQt QComboBox

QComboBox is a widget which provides a list of options to the user in a way that takes up the minimum amount of screen space. A combobox is a selection widget that displays the current item. It can pop up a list of selectable items.

A combobox may be editable and can contain icons.

The activated signal is sent when the user chooses an item in the combobox.

QComboBox example

The following example shows the selected item in a nearby label.

simple.py
#!/usr/bin/python

import sys

from PyQt5.QtWidgets import (QWidget, QLabel, QHBoxLayout,
                             QComboBox, QApplication)

class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):

        hbox = QHBoxLayout()

        self.lbl = QLabel('Ubuntu', self)

        combo = QComboBox(self)
        combo.addItem('Ubuntu')
        combo.addItem('Xubuntu')
        combo.addItem('Fedora')
        combo.addItem('Arch')
        combo.addItem('Gentoo')

        combo.activated[str].connect(self.onActivated)

        hbox.addWidget(combo)
        hbox.setSpacing(20)

        hbox.addWidget(self.lbl)
        self.setContentsMargins(20, 20, 20, 20)
        self.setLayout(hbox)

        self.move(300, 300)
        self.setWindowTitle('QComboBox')
        self.show()

    def onActivated(self, text):

        self.lbl.setText(text)
        self.lbl.adjustSize()


def main():
    
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

We have a combobox and a label. The selected item is displayed in the label.

combo = QComboBox(self)
combo.addItem('Ubuntu')
combo.addItem('Xubuntu')
...

A new item is added with addItem

combo.activated[str].connect(self.onActivated)

We connect the self.onActivated handler to the activate signal.

def onActivated(self, text):

    self.lbl.setText(text)
    self.lbl.adjustSize()

In the event handler, we set the selected text to the label and adjust the label's size to fit the text.

QComboBox
Figure: QComboBox

QComboBox icons

In the following example, we display icons with text in the combobox.

icons.py
#!/usr/bin/python

import sys
from PyQt5.QtWidgets import (QWidget, QHBoxLayout,
                             QComboBox, QApplication)
from PyQt5.QtGui import QIcon


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):

        hbox = QHBoxLayout()

        combo = QComboBox(self)
        combo.addItem('Disk')
        combo.setItemIcon(0, QIcon('disk.png'))
        
        combo.addItem('Web')
        combo.setItemIcon(1, QIcon('web.png'))

        combo.addItem('Computer')
        combo.setItemIcon(2, QIcon('computer.png'))

        hbox.addWidget(combo)
        hbox.setSpacing(20)
    
        self.setContentsMargins(20, 20, 20, 20)
        self.setLayout(hbox)

        self.setGeometry(300, 300, 250, 180)
        self.setWindowTitle('QComboBox')
        self.show()


def main():
    
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

The icon is set with the setItemIcon method.

Displaying icons in QComboBox
Figure: Displaying icons in QComboBox

QComboBox find text

The findItemText method returns the index of the item containing the given text. If the text was not found, it returns -1.

finding.py
#!/usr/bin/python

import sys

from PyQt5.QtWidgets import (QWidget, QLineEdit, QHBoxLayout, QPushButton,
                             QComboBox, QApplication)

class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):

        hbox = QHBoxLayout()

        data = ['sky', 'cloud', 'grass', 'water', 'glass', 'forest', 
            'rock', 'light', 'brittle', 'water', 'smoke']

        self.combo = QComboBox(self)
        self.combo.setMinimumWidth(90)
        self.combo.addItems(data)

        self.lineEdit = QLineEdit()
        self.lineEdit.setMinimumWidth(90)

        btn = QPushButton("Find")
        btn.clicked.connect(self.onClicked)

        hbox.addWidget(self.combo)
        hbox.setSpacing(20)
        hbox.addWidget(self.lineEdit)
        hbox.setSpacing(20)

        hbox.addWidget(btn)

        self.setContentsMargins(20, 20, 20, 20)
        self.setLayout(hbox)

        self.move(300, 300)
        self.setWindowTitle('QComboBox')
        self.show()

    def onClicked(self):

        data = self.lineEdit.text()
        idx = self.combo.findText(data)

        if idx != -1:
            self.combo.setCurrentIndex(idx)


def main():

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

In the example, we have a combobox, a line edit, and a push button. We search for the specified text, entered in the line edit. If the item text is found, it is displayed as the current text item.

data = ['sky', 'cloud', 'grass', 'water', 'glass', 'forest', 
    'rock', 'light', 'brittle', 'water', 'smoke']

self.combo = QComboBox(self)
self.combo.setMinimumWidth(90)
self.combo.addItems(data)

Multiple items are inserted with addItems.

def onClicked(self):

    data = self.lineEdit.text()
    idx = self.combo.findText(data)

    if idx != -1:
        self.combo.setCurrentIndex(idx)

When we click on the button, the onClicked handler is called. We retrieve the entered text with text. Then we find the index of the item which has the text. Finally, we set the current item with setCurrentIndex.

In this tutorial, we have presented the PyQt QComboBox widget.

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