title: How to show a custom uialertview created in interface builder
body: <p>I've created a custom uialertview in ib, with two button and a textfield.
  Then i create a .h and a .m in this way: </p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  
  @interface DialogWelcome : UIAlertView{
      IBOutlet UITextField *text;
      UIButton *ok;
      UIButton *annulla;
  }
  @property(nonatomic,retain) UITextField *text;
  - (IBAction)ok:(id)sender;
  - (IBAction)annulla:(id)sender;
  @end
  </code></pre>
  
  <p>and .m : </p>
  
  <pre><code>#import "DialogWelcome.h"
  
  @implementation DialogWelcome
  @synthesize text;
  
  -(IBAction)ok:(id)sender{
  
  }
  -(IBAction)annulla:(id)sender{
  
  }
  
  @end
  </code></pre>
  
  <p>i've not implement methods cause in first i need to show it!
  i call this in viewcontroller in this way:</p>
  
  <pre><code>- (void)viewDidLoad
  {
      [super viewDidLoad];
      DialogWelcome *alert = [[DialogWelcome alloc] initWithTitle:@"Welcome" 
                                                  message:nil 
                                                 delegate:nil 
                                        cancelButtonTitle:nil 
                                        otherButtonTitles:nil];
  
      [alert show];
      dispatch_time_t delay = dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_SEC*2.0);
      dispatch_after(delay, dispatch_get_main_queue(), ^{
          [alert dismissWithClickedButtonIndex:0 animated:YES];
      });
  
      [alert release];
  }
  </code></pre>
  
  <p>This will show a normal uialertview empty with a title. why it doesn't show my custom uialertview?</p>