Mahmood Kohansal Mahmood Kohansal - 3 years ago 262
Python Question

PyQt: Detect resizing in Widget-window resized signal

I create a simple UI with Qt Designer and convert it to Python codes. I searched for any method to detect changing window size.

This is the generated code :

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
def onResize(event):
print(event)

def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.setWindowTitle("MainWindow")
MainWindow.resize(200, 200)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
MainWindow.setCentralWidget(self.centralwidget)

MainWindow.resized.connect(self.someFunction)

QtCore.QMetaObject.connectSlotsByName(MainWindow)

if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())


I found a similar question QWidget resize signal? and this tutorial to handle size that recommended overriding resizeEvent method of QMainWindow.

But any of them doesn't solve my problem. Is there any resized function to detect window resizing like below:

MainWindow.resized.connect(self.someFunction)

Answer Source

There is no such signal by default, but you can create the resized signal, we emit it in the resizeEvent function.

For Example:

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.setWindowTitle("MainWindow")
        MainWindow.resize(200, 200)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        MainWindow.setCentralWidget(self.centralwidget)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)


class Window(QtWidgets.QMainWindow):
    resized = QtCore.pyqtSignal()
    def  __init__(self, parent=None):
        super(Window, self).__init__(parent=parent)
        ui = Ui_MainWindow()
        ui.setupUi(self)
        self.resized.connect(self.someFunction)

    def resizeEvent(self, event):
        self.resized.emit()
        return super(Window, self).resizeEvent(event)

    def someFunction(self):
        print("someFunction")


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Window()
    w.show()
    sys.exit(app.exec_())
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