PyQt5 – Magnify combobox when mouse is on it

In this article we will see how we can magnify the combo box when mouse is on it. Magnify means enlarging the size of the combo box when cursor is on it. We can’t change the size of combo box using style sheet therefore we can not use hover in stylesheet. In to know when mouse is on combo box we use underMouse method In order to do this we use underMouse method.

Syntax : combo_box.underMouse() Argument : It takes no argument Return : It returns bool

Steps for implementation : 1. Create a combo box. 2. Create a timer object which calls a function after every 100 milliseconds. 3. Inside the timer function check if the combo box is under mouse. 4. If combo box is under the mouse increase its size else make its size smaller. Below is the implementation – 

Python3

# importing libraries
from PyQt5.QtWidgets import *
from PyQt5 import QtCore, QtGui
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys


class Window(QMainWindow):

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

        # setting title
        self.setWindowTitle("Python ")

        # setting geometry
        self.setGeometry(100, 100, 600, 400)

        # calling method
        self.UiComponents()

        # showing all the widgets
        self.show()

    # method for widgets
    def UiComponents(self):
        # creating a check-able combo box object
        self.combo_box = QComboBox(self)

        # setting geometry of combo box
        self.combo_box.setGeometry(200, 150, 100, 30)

        # geek list
        geek_list = ["Sayian", "Super Sayian", "Super Sayian 2", "Super Sayian B"]

        # adding list of items to combo box
        self.combo_box.addItems(geek_list)

        # setting stylesheet of the combo box
        self.combo_box.setStyleSheet("border : 1px solid red;")

        # creating a timer object
        timer = QTimer(self)

        # adding action to the timer
        timer.timeout.connect(self.do_something)

        # starting timer
        timer.start(100)

    # action called by the timer
    def do_something(self):

        # checking if mouse is on combo box
        if self.combo_box.underMouse():
            # making size larger
            self.combo_box.resize(110, 40)

        else:
            # making size smaller
            self.combo_box.resize(100, 30)

# create pyqt5 app
App = QApplication(sys.argv)

# create the instance of our Window
window = Window()

# start the app
sys.exit(App.exec())

Output :