title: iOS: how to serialize a non-NSCoding compliant object
body: <p>I already take a look around and found the closes answer here:</p>
  
  <blockquote>
    <p><a href="https://stackoverflow.com/questions/5413851/correct-way-to-save-serialize-custom-objects-in-ios">Correct way to save/serialize custom objects in iOS</a></p>
  </blockquote>
  
  <p>But this is only applicable for custom objects that is user-created. My problem is serializing "SKProduct" which is a derived class that is non-NSCoding compliant. Specifically, the exact error I encountered:</p>
  
  <pre><code>-[SKProduct encodeWithCoder:]: unrecognized selector sent to instance 0x4027160
  </code></pre>
  
  <p>Does anyone have similar experience?</p>