title: cannot convert 'UIBarButtonItemStyle' to 'UIBarButtonSystemItem' in argument passing
body: <p>I am trying to add subview contains uipickerview and Done button using the following code </p>
  
  <pre><code>    pickerView = [[UIPickerView alloc]initWithFrame:CGRectMake(0,744, 768, 216)];
      mytab = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 700, 768, 44)];
  
      pickerView.alpha=0.0;
      mytab.alpha=0.0;
  
  
      pickerView.showsSelectionIndicator = YES;
      pickerView.dataSource = self;
      pickerView.delegate = self;
  
      [self.view addSubview:pickerView];
      [self.view bringSubviewToFront:pickerView]; 
  
  
      mytab.tintColor=[UIColor blackColor];
  
      UIBarButtonItem * bt1=[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonItemStylePlain target:self action:@selector(_cancel)];
      UIBarButtonItem * flx=[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil];
  
      NSArray *arr=[[NSArray alloc] initWithObjects:flx,bt1,nil];
      [mytab setItems:arr];
      [self.view addSubview:mytab];
  
      [UIView beginAnimations:nil context:nil];
      [UIView setAnimationDuration:0.3];
      pickerView.alpha=1.0;
      mytab.alpha=1.0;
      [UIView commitAnimations];
  
  
      [pickerView release];
      [mytab release];
      [bt1 release];
      [flx release];
      [arr release];
  </code></pre>
  
  <p>it raise the following error </p>
  
  <p>cannot convert 'UIBarButtonItemStyle' to 'UIBarButtonSystemItem' in argument passing</p>
  
  <p>aany suggestion to solve that </p>