Pyqt5 : dynamically change label value, with no clicking signal

Question

I have a question regarding PyQGIS.

I am currently developing a plugin, and I wish to update a window's label as soon as the window opens, without having to click on a button.

Here is what I do: I open my plugin, and when clicking on a button, it opens a second window. On that window, I have a label with a default value (that value comes from the ui file, created with QtCreator). The goal is, as soon as the window opens, to check another class attribute. If that attribute has a value, the label must be updated with that value. If the class attribute is 'None', then the label keeps the default value. I must not click on a button, or hover the text. However, I did not find any sort of signal allowing to check a label when a window opens.

I tried calling a method directly in the attribute definition, but it does not work:

class MySecondWindow(QtWidgets.QDialog, FORM_CLASS):
 def __init__(self, myInput, parent=None):
 super(MySecondWindow, self).__init__(parent)
 self.setupUi(self)
 self.myInfoClass = myInput
 self.myData = self.dynamicallyChangeLabel()
 self.dynamicallyChangeLabel()
 def dynamicallyChangeLabel(self):
 print("Checking label value")
 if self.myInfoClass.myInfoAttribute != None :
 self.myLabel.setText(self.myInfoClass.myInfoAttribute)

It seems the dynamicallyChangeLabel is not even called, since there is no print in my console.

Does anyone have an idea how to do this?

• Comrade Che: Is the self.myInfoClass.myInfoAttribute variable entered by the user through the plugin window? If yes, you can connect the input event to the label update.

Answer 1

In the end I used the showEvent method : it is called right away, without waiting for a user action.

def showEvent(self,showEvent):
 self.fillComboBox()

It is very useful !