Button to +1 in text box everytime it's clicked

[Axel_Erfurt]

You must create a window and connect the button to a function.

from PyQt5 import QtWidgets
 
class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent = None):
        super(MainWindow, self).__init__(parent)
        self.setup_ui()
    
    def setup_ui(self):
        toolbar = self.addToolBar("Tools")
        self.count_button = QtWidgets.QPushButton("+")
        self.count_button.clicked.connect(self.on_btn_clicked)
        toolbar.addWidget(self.count_button)
 
        self.text_browser = QtWidgets.QTextBrowser()      
        self.text_browser.setText("0")
        self.setCentralWidget(self.text_browser)
        
        self.counter = 1
                
        self.resize(656, 383)
        
    def on_btn_clicked(self):
        self.text_browser.setText(f"{self.counter}")
        self.counter += 1

        
if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    win = MainWindow()
    win.setWindowTitle("MainWindow")
    win.show()
    sys.exit(app.exec_())

or use a Spinbox

from PyQt5 import QtWidgets
 
class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent = None):
        super(MainWindow, self).__init__(parent)
        self.setup_ui()
    
    def setup_ui(self):
        toolbar = self.addToolBar("Tools")
        
        self.spin_box = QtWidgets.QSpinBox()
        self.spin_box.valueChanged.connect(self.on_spin_box)
        toolbar.addWidget(self.spin_box)
 
        self.text_browser = QtWidgets.QTextBrowser()      
        self.text_browser.setText("0")
        self.setCentralWidget(self.text_browser)
                
        self.resize(656, 383)
        
    def on_spin_box(self):
        self.text_browser.setText(f"{self.spin_box.value()}")

        
if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    win = MainWindow()
    win.setWindowTitle("MainWindow")
    win.show()
    sys.exit(app.exec_())