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copied!<p>This one is with using static methods</p> <pre><code><?php class ClassA { function Draw() { echo "DrawA"; /* Drawing code ... */ } function InvokeDraw() { self::Draw(); } } class ClassB extends ClassA { function Draw() { echo "DrawB"; parent::InvokeDraw(); /* Drawing code ... */ } } echo "Begin:<br>"; $cb = new ClassB(); $cb->Draw(); </code></pre> <p>Note that the only thing I changed is the <code>InvokeDraw()</code> method and made it use <code>self</code> which refers to a class, rather than object as it is with <code>$this</code></p> <p>Output:</p> <pre><code>Begin: DrawBDrawA </code></pre> <p><strong>Edit:</strong> To answer your comment below I will add a short description of how your code works and how this code works.</p> <p>What happens in your code:</p> <ol> <li>We create <code>B</code> and start working with it</li> <li>We call <code>B->Draw()</code> while working within <code>B</code> class AND <code>B</code> object.</li> <li><code>B->Draw()</code> calls statically(that means class method) <code>A::Invoke()</code> from class A <strong>BUT</strong> we are still using <code>B</code> object.</li> <li>Static call <code>A::Invoke()</code> calls <code>$this->Draw();</code> and as we are working currently with <code>B</code> object, <code>$this</code> refers to an instance of <code>ClassB</code>.</li> <li>And here we go looping.</li> </ol> <p>What happens in the code above:</p> <ol> <li>We create <code>B</code> and start working with it</li> <li>We call <code>B->Draw()</code> while working within <code>B</code> class AND <code>B</code> object.</li> <li><code>B->Draw()</code> calls statically(that means class method) <code>A::Invoke</code> from class A <strong>BUT</strong> as well as in your code we are still using <code>B</code> object.</li> <li>Static call <code>A::Invoke()</code> calls <code>self::Draw()</code> which is basically the same as <code>ClassA::Draw()</code> and because it's a static method, we don't care what object we are currently working with and we call the <code>A</code>'s <code>Draw()</code> method.</li> <li><code>A::Draw()</code> method executes as we need.</li> </ol> <p>I will provide the same explanation for the code in my second answer, which doesn't use static calls:</p> <ol> <li>We create <code>B</code> and start working with it</li> <li>We call <code>B->Draw()</code> while working within <code>B</code> class AND <code>B</code> object.</li> <li><code>B->Draw()</code> <strong>CREATES</strong> an instance of <code>A</code>.</li> <li><code>B->Draw()</code> calls <code>A->Invoke()</code> which means we start to work with an object that is instance of class <code>A</code> and not <code>B</code> like before.</li> </ol> <p><em>At this point we completely forget that <code>B</code> even exists and work only with <code>A</code></em></p> <ol> <li><code>A->Invoke()</code> calls <code>$this->Draw()</code> which means that we are calling <code>A->Draw()</code>, because we already work with an instance of class <code>A</code>.</li> <li><code>A->Draw()</code> executes as we expect.</li> </ol> <p>From usability point of view, we can see that the static method is better, as we can define some static properties and you can work with them when <code>A::Draw()</code> executes. If we use non-static method, then we need to pass the data we need within arguments of our methods.</p> <p>I hope this makes it clear. The sequences above do not have the right terminology, but it was written on purpose, I think it's easier to understand the flow that way.</p>

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