Setting the UIImagePickerController delegate throws a warning about UINavigationControllerDelegate
<p>The code:</p>

<pre><code>UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.sourceType = UIImagePickerControllerSourceTypeCamera;
[self.navigationController presentModalViewController:picker animated:YES];
[picker release];
</code></pre>

<p>The warning, which shows up on the <code>picker.delegate = self;</code> line:</p>

<pre><code>Class 'CardEditor' does not implement the 'UINavigationControllerDelegate' protocol
</code></pre>

<p>Why does the UIImagePickerController care if my class implements the UINavigationControllerDelegate protocol?</p>
