Question

My App的结构喜欢这个：

UISplitViewController:

the master:NavigationController1->UITableViewController

the detail:NavigationController2->UIWebViewController

我希望在iPad上使用纵向模式时显示barButtonItem 我知道如何通过willHideViewController在iOS7中实现它：

-(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;
    }
}

但是，此方法在iOS 8中已弃用，我尝试使用：

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

此方法仅在显示模式更改时有效，但在应用程序首次以纵向方向启动时才有效。那么如何在第一次以纵向方向加载应用时显示barButtonItem。

Answer 1

您可以在视图控制器显示时添加条形按钮：

- (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;
    }
}

这只会在主人当前被隐藏时添加按钮。

Answer 2

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

    if (self.splitViewController.displayMode == UISplitViewControllerDisplayModePrimaryHidden){
        self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Course" style:self.splitViewController.displayModeButtonItem.style target:self.splitViewController.displayModeButtonItem.target action:self.splitViewController.displayModeButtonItem.action];
    }
}

-(void)splitViewController:(UISplitViewController *)svc willChangeToDisplayMode:(UISplitViewControllerDisplayMode)displayMode{
    if (displayMode == UISplitViewControllerDisplayModePrimaryHidden) {
        self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Course" style:svc.displayModeButtonItem.style target:svc.displayModeButtonItem.target action:svc.displayModeButtonItem.action];
    }else{
        self.navigationItem.leftBarButtonItem = nil;
    }
}

如何在使用splitViewController时显示barButtonItem：willChangeToDisplayMode：在iOS8中

2 个答案: