title: PyQt show one widget by clicking button on another
body: <p>I'm new in PyQt and using PyQt4. Have two independent widgets. First of them <code>showFullScreen()</code> and second <code>show()</code>. I want after hiding second by <code>hide()</code> show it by clicking button on first. Tried something and googled - nothing.
  Full code:</p>
  
  <pre><code>from PyQt4 import QtCore, QtGui
  
  
  class FileExplorer(QtGui.QWidget):
      def __init__(self, parent=None):
          super(FileExplorer, self).__init__(parent)
  
          nameLabel = QtGui.QLabel("Name:")
          self.nameLine = QtGui.QLineEdit()
  
          addressLabel = QtGui.QLabel("Address:")
          self.addressText = QtGui.QTextEdit()
  
          showButton = QtGui.QPushButton('Show widget', self)
          showButton.clicked.connect(FileExplor.show)
  
          mainLayout = QtGui.QGridLayout()
          mainLayout.addWidget(nameLabel, 0, 0)
          mainLayout.addWidget(self.nameLine, 0, 1)
          mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
          mainLayout.addWidget(self.addressText, 1, 1)
          mainLayout.addWidget(showButton, 3, 1)
  
          self.setLayout(mainLayout)
  #               self.setGeometry(300, 300, 250, 150)
  #        self.sizeHint()
          self.setWindowTitle("File Explorer")
  
  
  
  
  class FileExplor(QtGui.QWidget):
      def __init__(self, parent=None):
          super(FileExplor, self).__init__(parent)
  
          nameLabel = QtGui.QLabel("Name:")
          self.nameLine = QtGui.QLineEdit()
  
          addressLabel = QtGui.QLabel("Address:")
          self.addressText = QtGui.QTextEdit()
  
          quitButton = QtGui.QPushButton('Quit', self)
          quitButton.clicked.connect(self.hide)
  
          mainLayout = QtGui.QGridLayout()
          mainLayout.addWidget(nameLabel, 0, 0)
          mainLayout.addWidget(self.nameLine, 0, 1)
          mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
          mainLayout.addWidget(self.addressText, 1, 1)
          mainLayout.addWidget(quitButton, 3, 1)
  
          self.setLayout(mainLayout)
          #self.setGeometry(300, 300, 250, 150)
          self.sizeHint()
          self.setWindowTitle("File Explorer")
  
  
  if __name__ == '__main__':
      import sys
  
      app = QtGui.QApplication(sys.argv)
  
      fileExplorer = FileExplorer()
      fileExplorer.showFullScreen()
  #    fileExplorer.show()
  #
      fileExplor = FileExplor()
      fileExplor.show()
  
      sys.exit(app.exec_())
  </code></pre>
  
  <p>Logic what i want make in the end:</p>
  
  <ul>
  <li>first widget - main block (fullscreen)</li>
  <li>other widgets - can be show by clicking buttons in first</li>
  </ul>