title: How to set focus on a widget at app startup?
body: <p>I'm trying to set the focus on <code>QLineEdit</code> widget at app startup but for some reasons it fails. Calling the method which includes the <code>QLineEdit_object.setFocus()</code> and is bound to a button click, works perfectly. However on startup, it seems like it doesn't execute at all when set to initialize after widget creation.</p>
  
  <p>Using PySide with Python.</p>
  
  <pre><code># coding=utf-8
  import sys
  import PySide.QtGui as QG
  import PySide.QtCore as QC
  
  class GG(QG.QMainWindow):
      def __init__(self):
          super(GG, self).__init__()
          self.move(0,0)
          self.resize(400,300)
          self.setWindowTitle('Demo')
  
          self.tabw = QG.QTabWidget()
          self.tab1 = Tab1()
          self.tab2 = Tab2()
  
          self.tabw.addTab(self.tab1, 'Tab1')
          self.tabw.addTab(self.tab2, 'Tab2')
  
          hbox = QG.QHBoxLayout()
          hbox.addWidget(self.tabw)
  
          self.setCentralWidget(self.tabw)
          self.setLayout(hbox)
          self.show()
  
  class Tab1(QG.QWidget):
      def __init__(self):
          super(Tab1, self).__init__()
  
          self.btns()
          self.inputt()
          self.layoutz()
          self.inp.setFocus() # doesn't set the focus on startup ?
          self.show()
  
      def inputt(self):
          self.inp = QG.QLineEdit('', self)
  
      def btns(self):
          self.btn1 = QG.QPushButton('Button1', self)
          self.btn1.clicked.connect(self.focusit) # works just fine
  
      def layoutz(self):
          vbox = QG.QVBoxLayout()   
          vbox.addWidget(self.btn1)
          vbox.addStretch(1)
          vbox.addWidget(self.inp)
          self.setLayout(vbox)
  
      def focusit(self):
          self.inp.setFocus() # works just fine
  
  
  class Tab2(Tab1):
      def __init__(self):
          super(Tab2, self).__init__()
  
  
  def main():
      app = QG.QApplication(sys.argv)
      a = GG()
      sys.exit(app.exec_())
  
  if __name__ == '__main__':
     main()
  </code></pre>