title: how to set validator with QDoubleValidator? (QValidator)
body: <p>I now have a class called EditBox which inherit from Qwidget and QTextEdit</p>
  
  <p>And I'm trying to set a validator to this text edit box....</p>
  
  <pre><code>EditBox manbox;
  </code></pre>
  
  <p>How do I set up a validator to 0~100? with 2 decimal point?</p>
  
  <p>I've tried </p>
  
  <pre><code>QDoubleValidator *testQD = new QDoubleValidator(manbox);
  testQD-&gt;setRange(0.00,100.00,2);
  
  QLineEdit *sb1 = new QLineEdit( manbox );
  sb1-&gt;setValidator(testQD);
  </code></pre>
  
  <p>but seems not working. Any where went wrong?</p>
  
  <p>Or please guide me somewhere i can find full tutorial for this one.
  Thanks!</p>