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POInitialize an object with a superclass' instance
 

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    <p>Let's say a have a <code>Superclass</code> and an instance of this class <code>superclassObject</code>.<br> I create a derived <code>ClassA</code>. </p> <p>How can I instantiate (initialize) an object <code>classAObject</code> of the derived class in a such way, that all the inherited fields are equal to ones of <code>superclassObject</code>? </p> <p>Of course I can cycle through all the fields and manually copy the values like <code>classAObject.property = [superclassObject.property copy]</code>. But the problem with this approach is that I may not know (or have access to) all the ivars/properties of the superclass. Is there an easier (and more general) way?</p> <p>It seems that I'm missing something really basic...</p> <p>I'm trying to do this because I get an already initialized UIView (with frame, background color, autoresizing mask, etc.) and I want to replace it with my custom view with same parameters.</p> <h3>Update 1</h3> <p>I've found <a href="https://stackoverflow.com/questions/4872155/how-to-initialize-an-object-of-subclass-with-an-existing-object-of-superclass-i">this question</a>, and the answer there says that it</p> <blockquote> <p>generally isn't supported in any OO language</p> </blockquote> <p>however</p> <blockquote> <p>In Objective-C it is possible in some cases</p> </blockquote> <p>Ok, if it's <strong>not</strong> supported, what should I do? If it <strong>is</strong> supported, how can I achieve this?</p> <h3>Update 2</h3> <p>It seems I've found a solution to my particular case of this general problem, which I'll test and report that tomorrow.</p> <p>However, this lead me to another idea: What if I use a NSCoder to encode the <code>superclassObject</code> (if it implements <code>&lt;NSCoding&gt;</code> of course), and then call <code>[[ClassA alloc] initWithCoder:coder]</code> with a coder that knows data from the encoded <code>superclassObject</code>? <em>Disclaimer:</em> Well, I'm not that familiar with coding concepts (or even not at all), so may be the last sentence is nonsense.</p>
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    1. COYou initialize it has you would any normal object. The problems you are facing are probably with the superclass permissions and Superclass init function(constructor).
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    2. CO@Radu, you didn't understand my question. The ivars of the superclass instance are already set, but **not** to default values. I need to copy them.
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    3. CODoes your subclass add any instance variables of its own, or are the fields the same as the superclass? I.e., are you only creating new methods?
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      1. USJosh Caswell
 

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