access element from .ui

Question

I have problem to access my button and label from my dialog.ui. I am using Python 3.x and QT Designer 5.x.

from PyQt5 import uic, QtWidgets
from PyQt5.QtWidgets import QApplication

Form, Window = uic.loadUiType("dialog.ui")      #load ui (GUI) file

app = QApplication([])  #create a QApplication

window = Window()                               

form = Form()
form.setupUi(window)

def on_click():
    # self.qlFreeText.text("hello")
    alert = QMessageBox()
    alert.setText("You clicked the button!")
    alert.exec_()

class Ui(QtWidgets.QMainWindow):
    def __init__(self):
        super(Ui, self).__init__()
        uic.loadUi('basic.ui',self)

        # self.ButtonSearch = self.findChild(QtWidgets.QPushButton, 'qpbSearch')    
        self.ButtonSearch = self.findChild(QtWidgets.QObject, 'qpbSearch')  
        self.ButtonSearch.button.clicked.connect(self.printButtonPressed)

        self.qlFreeText = self.findChild(QWidgets.QLabel, 'qlFreeText') 

        # self.show()

    def printButtonPressed(self):
        on_click()


window.show()       #show window

app.exec_()         #run application until user closes it

dialog.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Dialog</class>
 <widget class="QDialog" name="Dialog">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Dialog</string>
  </property>
  <widget class="QDateEdit" name="dateStart">
   <property name="geometry">
    <rect>
     <x>50</x>
     <y>50</y>
     <width>110</width>
     <height>22</height>
    </rect>
   </property>
   <property name="displayFormat">
    <string>yyyy-MM-dd</string>
   </property>
  </widget>
  <widget class="QDateEdit" name="dateEnd">
   <property name="geometry">
    <rect>
     <x>220</x>
     <y>50</y>
     <width>110</width>
     <height>22</height>
    </rect>
   </property>
   <property name="displayFormat">
    <string>yyyy-MM-dd</string>
   </property>
  </widget>
  <widget class="QLabel" name="qlFreeText">
   <property name="geometry">
    <rect>
     <x>120</x>
     <y>140</y>
     <width>55</width>
     <height>16</height>
    </rect>
   </property>
   <property name="text">
    <string>TextLabel</string>
   </property>
  </widget>
  <widget class="QPushButton" name="qpbSearch">
   <property name="geometry">
    <rect>
     <x>190</x>
     <y>220</y>
     <width>93</width>
     <height>28</height>
    </rect>
   </property>
   <property name="text">
    <string>PushButton</string>
   </property>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>

When I click on the button, nothing happens. What I would like to try is, when I click on the button, than it changes the label text. But currently I can even not use the click on the button.

Answer 1

You are confusing the following concepts:

• You are creating the UI class where you create the connection but never use it. How do you think something works?

• You don't need to use findChild() since if you use loadUi or loadUiType it will map the objects using the objectName.

Considering the above, the solutions are as follows:

loadUi():

from PyQt5 import uic, QtWidgets


class Ui(QtWidgets.QDialog):
    def __init__(self):
        super(Ui, self).__init__()
        uic.loadUi("dialog.ui", self)
        self.qpbSearch.clicked.connect(self.printButtonPressed)

    def printButtonPressed(self):
        self.qlFreeText.setText("hello")

        alert = QtWidgets.QMessageBox()
        alert.setText("You clicked the button!")
        alert.exec_()


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = Ui()
    w.show()  # show window
    sys.exit(app.exec_())

loadUiType():

from PyQt5 import uic, QtWidgets

Form, _ = uic.loadUiType("dialog.ui")


class Ui(QtWidgets.QDialog, Form):
    def __init__(self):
        super(Ui, self).__init__()
        self.setupUi(self)
        self.qpbSearch.clicked.connect(self.printButtonPressed)

    def printButtonPressed(self):
        self.qlFreeText.setText("hello")

        alert = QtWidgets.QMessageBox()
        alert.setText("You clicked the button!")
        alert.exec_()


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = Ui()
    w.show()  # show window
    sys.exit(app.exec_())

---

I recommend you check Using Qt Designer.

Answer 2

from PyQt5 import QtWidgets, uic
import sys


def clicked_me():
    print("You Clicked Me! :-)")


app = QtWidgets.QApplication([])
win = uic.loadUi("main_window.ui")

win.btn_start_capture.clicked.connect(clicked_me)
# My Button's Name is btn_start_capture

win.show()
sys.exit(app.exec())

Answer 3

In my file, This is how I did it.

Loading User Interface

self.ui = uic.loadUi('pyqt-gui-form.ui', self)

The name of object is save_credentials_btn

self.ui.save_credentials_btn.clicked.connect(self.save_user)

Whole file

from PyQt6.QtWidgets import QApplication, QWidget
import sys # This module provides access to some variables used or maintained by the interpreter and to functions that interact strongly with the interpreter. It is always available.
from PyQt6 import uic


class Window(QWidget):
    def __init__(self):
        super().__init__()
        # LOAD UI FILE
        self.ui = uic.loadUi('pyqt-gui-form.ui', self)
        self.ui.save_credentials_btn.clicked.connect(self.save_user)

    def save_user(self):
        print("Save User")

app = QApplication([])
window = Window()
window.show()
sys.exit(app.exec())