title: UIAlertview not adding UIDatePicker when i click on textfield?
body: <p>UIAlertview not adding UIDatePicker when i click on textfield?       </p>
  
  <pre><code>- (void)textFieldDidBeginEditing:(UITextField *)textField
  {
      UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Preferences"
                                                  message:@"\n\n\n\n\n\n\n"
                                                 delegate:self
                                        cancelButtonTitle:@"Cancel"
                                        otherButtonTitles:@"OK", nil];
      pickerView=[[UIDatePicker alloc]initWithFrame:CGRectMake(0,40,246,150)];
      pickerView.datePickerMode=UIDatePickerModeDate;
      [alert addSubview:pickerView];
      [alert show];
  }
  </code></pre>