UIBarButtonItem *doneNavigationBarButton = [[UIBarButtonItem alloc] initWithTitle:@"Tool" style:UIBarButtonItemStylePlain target:self action:@selector(doneNavigationBarButtonClicked)];
[[self navigationItem] setRightBarButtonItem: doneNavigationBarButton];
[doneNavigationBarButton release];

And make a method
- (void)doneNavigationBarButtonClicked
{   NSLog(@"Done button Clicked");
}

if(isDoneVisible==YES)
{
 [DoneButton setHidden:NO];
}
else
{
[DoneButton setHidden:YES];
}