title: Cannot find protocol definition for XXX
body: <p>I have declared a protocol firstly, and then use it. But I get a warning "Cannot find protocol definition for LeveyPopListViewDelegate".
  Here is the code:</p>
  
  <pre><code>@protocol LeveyPopListViewDelegate;
  
  @interface LeveyPopListView : UIView &lt;LeveyPopListViewDelegate,UITableViewDataSource,   UITableViewDelegate,UITextFieldDelegate&gt;
  
  //the content of LeveyPopListView
  
  @end
  
  @protocol LeveyPopListViewDelegate &lt;NSObject&gt;
  //the definition for LeveyPopListViewDelegate
  @end
  </code></pre>
  
  <p>if I put the definition <code>LeveyPopListViewDelegate</code> at first, I can not use the <code>LeveyPopListView</code> in the protocol.</p>