import sys
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *


class App(QWidget):

    def __init__(self):
        super().__init__()
        self.resize(400, 200)
        self.edit_number = QLineEdit()
        self.label = QLabel('Введите число')
        self.button = QPushButton('нажми для начала')
        self.button.clicked.connect(self.clicked)
        layout = QVBoxLayout()
        layout.addWidget(self.label)
        layout.addWidget(self.edit_number)
        layout.addWidget(self.button)
        self.setLayout(layout)

    def clicked(self):
        self.dialog = Dialog(self)
        self.dialog.exec()


class Dialog(QDialog):
    def __init__(self, main):
        super().__init__()
        self.g = 1
        self.resize(400, 100)
        self.main = main
        self.label_dialog = QLabel()
        self.button_stop = QPushButton('Остановись')
        self.button_stop.clicked.connect(self.function_stop)
        layout_dialog = QVBoxLayout()
        layout_dialog.addWidget(self.label_dialog)
        layout_dialog.addWidget(self.button_stop)
        self.setLayout(layout_dialog)
        self.timer = QTimer()
        self.timer.timeout.connect(self.select)
        self.timer.start(1000)

    def select(self):
        self.i = int(self.main.edit_number.text())
        if self.g <= self.i:
            self.label_dialog.setText(str(self.g))
            self.g += 1

        else:
            self.reply = QMessageBox.information(self, 'Message', "Все сделано")
            if self.reply:
                self.timer.stop()
                self.main.edit_number.clear()
                self.close()

    def function_stop(self):
        self.timer.stop()
        self.reply = QMessageBox.information(self, 'Message', "Расчет был прерван последнее "
                                                              "число было равно = " + str(self.g))
        self.main.edit_number.clear()
        self.close()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    ex.show()
    sys.exit(app.exec_())