Keyboard is not enabling after navigation takes place in ios

Question

While I am navigating to the particular controller I want keyboard to enable after the navigation takes place. In IndexPageTableViewController it has a textField named searchField I need to enable the keyboard.

-(void) navigateToSearch
{
UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Main_iPhone"
                                                         bundle: nil];
if(mainStoryboard)
{
    IndexPageTableViewController *index = (IndexPageTableViewController *) [mainStoryboard instantiateViewControllerWithIdentifier:@"IndexPageTableViewController"];
    [[SlideNavigationController sharedInstance ] popToRootAndSwitchToViewController:index withSlideOutAnimation:NO andCompletion:^{
        [self initTableView];

        [self becomeFirstResponder];
    }];


     }
     }