how to show barButtonItem when using splitViewController:willChangeToDisplayMode: in iOS8

Question

My App's structure likes this:

UISplitViewController:

the master:NavigationController1->UITableViewController

the detail:NavigationController2->UIWebViewController

I want to show the barButtonItem when the view goes on portrait mode on iPad and I know how to realize it in iOS7 by willHideViewController:

-(void)splitViewController:(UISplitViewController *)svc willHideViewController:(UIViewController *)aViewController withBarButtonItem:(UIBarButtonItem *)barButtonItem forPopoverController:(UIPopoverController *)pc{
        barButtonItem.title = @"Course";
        self.navigationItem.leftBarButtonItem = barButtonItem;
}

-(void)splitViewController:(UISplitViewController *)svc willShowViewController:(UIViewController *)aViewController invalidatingBarButtonItem:(UIBarButtonItem *)barButtonItem{
    if (barButtonItem == self.navigationItem.leftBarButtonItem) {
         self.navigationItem.leftBarButtonItem = nil;
    }
}

However, this method is deprecated in iOS 8, and i tried to use:

-(void)splitViewController:(UISplitViewController *)svc willChangeToDisplayMode:(UISplitViewControllerDisplayMode)displayMode{
    if (displayMode == UISplitViewControllerDisplayModePrimaryHidden) {
        self.navigationItem.leftBarButtonItem = svc.displayModeButtonItem;
    }else{
        self.navigationItem.leftBarButtonItem = nil;
    }
}

This method only works when the display mode changes but not when the app first starts with a portrait orientation. So how to show barButtonItem when loading the app first time with a portrait orientation.

Answer 1

You can add the bar button when your view controller shows up:

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    if (self.splitViewController.displayMode == UISplitViewControllerDisplayModePrimaryHidden)
    {
        UIBarButtonItem *barButtonItem = self.splitViewController.displayModeButtonItem;
        barButtonItem.title = @"Show master";
        self.navigationItem.leftBarButtonItem = barButtonItem;
    }
}

This will only add the button when the master is currently hidden.