title: NSUrl is not stored as absolutestring in NSUserDefault
body: <p>I am referring <a href="https://stackoverflow.com/questions/3818532/iphone-save-url-without-seturlforkey-and-nsurl">Previous Post</a> for storing NSURL of iPod Library in NSUserDefault. But it is not stored in NSUserDefault after application is closed.</p>
  
  <p>I am using other NSStrings to store in NSUserDefaults which is perfectly done, But when i store NSUrl as absolute string.. it does not stores the value.</p>
  
  <p>What could be the reason??</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>Following code i am using to save NSUserDefault Value:</p>
  
  <pre><code>currentItem = [collection.items objectAtIndex:songCount];
  songURL = [currentItem valueForProperty:MPMediaItemPropertyAssetURL];
  [[NSUserDefaults standardUserDefaults] setObject:[currentItem valueForProperty:MPMediaItemPropertyTitle] forKey:@"songTitle"];
  [[NSUserDefaults standardUserDefaults] setObject:[songURL absoluteString] forKey:@"songURL"];
  avPlayer = [[AVPlayer alloc] initWithURL:songURL];
  NSLog(@"songTitle: %@  songURL : %@",[[NSUserDefaults standardUserDefaults]objectForKey:@"songTitle"], songURL);
  </code></pre>
  
  <p>Following error comes when i try to save the NSURL:</p>
  
  <pre><code>2011-09-13 18:47:23.258 Tabata Timer[933:707] songURL : ipod-library://item/item.mp3?id=-3715406019015217536
  2011-09-13 18:47:23.258 Tabata Timer[933:707] *** -[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value 'ipod-library://item/item.mp3?id=-3715406019015217536' of class 'NSURL'.
  2011-09-13 18:47:23.260 Tabata Timer[933:707] songTitle : Ghajini
  2011-09-13 18:47:24.860 Tabata Timer[933:707] *** -[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value 'ipod-library://item/item.mp3?id=-3715406019015217536' of class 'NSURL'.
  2011-09-13 18:47:24.963 Tabata Timer[933:707] songURL : ipod-library://item/item.mp3?id=-3715406019015217536
  warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.3.5 (8L1)/Symbols/Developer/usr/lib/libXcodeDebuggerSupport.dylib (file not found).
  </code></pre>