title: viewDidAppear not firing ever again after app enters foreground
body: <p>I have traced a problem in my iPhone app code to the viewDidAppear method not always firing.  When you start the app the event fires as expected.  However if I close the app using a phone capable of multitasking and reopen in.  My viewDidAppear events no longer fire.</p>
  
  <p>My views are loaded from Nibs and I use viewDidUnload to clean up (release and nil all outlets).  My views are nested in side and tab bar then navigation controllers.  I looks like the events aren't wired up properly when the nibs reload.  Any idea on what I'm doing wrong/missing and how I can fix this?  </p>
  
  <p>Thanks in advance.</p>
  
  <p><strong>UPDATE</strong> I do not mean the event is not fired when the app first comes into the foreground.  I mean the event never fires again.  Even when changing between tabs or moving though the navigation views.</p>
  
  <p>Example:</p>
  
  <pre><code>- (void)viewDidAppear:(BOOL)animated {
     [super viewDidAppear:animated];
     NSLog(@"viewDidAppear called");
  }
  </code></pre>
  
  <p>This code is placed in two views, each on different tabs.  Each time I swap between tabs "viewDidAppear called" is written to the log.  When I close and reopen the app and swap between tabs this no longer happens.  Other button events fire normally.</p>