import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QDialog
from mainWindow import Ui_MainWindow
from connection import Ui_Form

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        self.ui.actionConnect_DB.triggered.connect(self.open_connection)

    def open_connection(self):
        self.connection_window = ConnectionWindow(self)
        self.connection_window.show()

class ConnectionWindow(QDialog):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.ui = Ui_Form()
        self.ui.setupUi(self)
        self.ui.saveButton.setEnabled(False)

    def customSlot(self, text):
        if self.ui.IP.text():
            self.ui.saveButton.setEnabled(True)
        else:
            self.ui.saveButton.setEnabled(False)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())