title: Update Clock and Text in UI PyQt5
body: <p>I have a problem to put the actual time while the UI is running, also the text y would like to change it in a certain period of time. I also try to use MainWindow.update() in my case Reloj.update() but it continue with the same problem, put it with an loop it's a bad idea.</p>
  
  <p>I will put some code just to see how is working</p>
  
  <p>The Ui is made by QtDesigner and then export to python.
  My problem is that I have an UI that it shows all but it doesn't update the clock and the text.
  I want to put the actual time while the UI is running.
  Also the text is going to change in a certain period of time. I want to change the text after 15 minutes, but in this case I put a "delay" of 15 seconds, And the Ui doesn't change.</p>
  
  <p>Also i try to update the Ui using Reloj.update(), but it doesn't change too.</p>
  
  <p>Here is the example:</p>
  
  <pre><code>from PyQt5 import QtCore, QtGui, QtWidgets
  import time
  
  class Ui_Reloj(object):
      def setupUi(self, Reloj):
          Reloj.setObjectName("Reloj")
          Reloj.resize(400, 300)
          self.centralWidget = QtWidgets.QWidget(Reloj)
          self.centralWidget.setObjectName("centralWidget")
          self.gridLayout = QtWidgets.QGridLayout(self.centralWidget)
          self.gridLayout.setContentsMargins(11, 11, 11, 11)
          self.gridLayout.setSpacing(6)
          self.gridLayout.setObjectName("gridLayout")
          self.Texto = QtWidgets.QLabel(self.centralWidget)
          self.Texto.setObjectName("Texto")
          self.gridLayout.addWidget(self.Texto, 0, 0, 1, 1)
          self.Reloj_2 = QtWidgets.QLCDNumber(self.centralWidget)
          self.Reloj_2.setObjectName("Reloj_2")
          self.gridLayout.addWidget(self.Reloj_2, 0, 1, 1, 1)
          Reloj.setCentralWidget(self.centralWidget)
          self.menuBar = QtWidgets.QMenuBar(Reloj)
          self.menuBar.setGeometry(QtCore.QRect(0, 0, 400, 20))
          self.menuBar.setObjectName("menuBar")
          Reloj.setMenuBar(self.menuBar)
          self.mainToolBar = QtWidgets.QToolBar(Reloj)
          self.mainToolBar.setObjectName("mainToolBar")
          Reloj.addToolBar(QtCore.Qt.TopToolBarArea, self.mainToolBar)
          self.statusBar = QtWidgets.QStatusBar(Reloj)
          self.statusBar.setObjectName("statusBar")
          Reloj.setStatusBar(self.statusBar)
  
          self.retranslateUi(Reloj)
          QtCore.QMetaObject.connectSlotsByName(Reloj)
  
          """ Reloj """
          time = QtCore.QTime.currentTime()
          texto_reloj = time.toString('HH:mm')
          if (time.second() % 2) == 0:
                  texto_reloj = texto_reloj[:2] + ' ' + texto_reloj[3:]
  
          self.Reloj_2.display(texto_reloj)
  
          """ Texto que Cambia """
          vec = ['Hola','Que Tal?', 'No se toca', 'paradise']
          self.cambiar_texto(vec)
  
      def retranslateUi(self, Reloj):
          _translate = QtCore.QCoreApplication.translate
          Reloj.setWindowTitle(_translate("Reloj", "Reloj"))
          self.Texto.setText(_translate("Reloj", "Texto que cambia"))
  
      def showTime(self):
          time = QtCore.QTime.currentTime()
          text = time.toString('HH:mm')
          if (time.second() % 2) == 0:
              text = text[:2] + ' ' + text[3:]
          self.Reloj_2.display(text)
  
      """ Cambiar Texto cada X tiempo (ejemplo 15 Minutos) """
      def cambiar_texto (self,vec):
          i=0
          length_string = len(vec)
          time.sleep(15)
          self.Texto.setText(vec[i])
          if (i == 3):
              i=0
          else:
              i+=1
  
  if __name__ == "__main__":
      import sys
      app = QtWidgets.QApplication(sys.argv)
      Reloj = QtWidgets.QMainWindow()
      ui = Ui_Reloj()
      ui.setupUi(Reloj)
      Reloj.show()
      sys.exit(app.exec_())
  </code></pre>
  
  <p>There is no errors while it's compiling, but it should update the clock and the text. </p>