from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow
import sys


class MyWindow(QMainWindow):
    clicked_times = 0

    def __init__(self):
        super(MyWindow, self).__init__()
        self.setGeometry(200, 200, 300, 300)
        self.setWindowTitle("Armando's First test !")
        self.initUI()

    def initUI(self):
        self.label = QtWidgets.QLabel(self)
        self.label.setText("This is label")
        self.label.move(50, 50)

        self.b1 = QtWidgets.QPushButton(self)
        self.b1.setText("Click aqui !")
        self.b1.clicked.connect(self.clicked)

    def clicked(self):
        self.clicked_times += 1
        self.label.setText("You pressed the button {} times".format(self.clicked_times))
        self.update()

    def update(self):
        self.label.adjustSize()


def window():
    app = QApplication(sys.argv)
    win = MyWindow()
    win.show()
    sys.exit(app.exec())


window()