错误应用试图呈现拆分视图控制器模态

Question

我用故事板，我想加载一组特定的XIBs的，问题是，我得到这个错误：

'NSInvalidArgumentException', reason: 'Application tried to present a Split View Controllers modally <PlaceHolderViewController: 0x38e890> 

在PlaceHolderViewController我有一个按钮，用这段代码加载xib，我没有问题从iPhone加载xib，但在iPad上我遇到了这个问题。

这是代码：

- (IBAction)actionButtonConversor:(id)sender { 
    ConverterViewController *converterViewController; 
    UnitSelectViewController *unitSelectViewController; 

    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) { 
     converterViewController = [[ConverterViewController alloc] initWithNibName:@"ConverterViewController_iPhone" bundle:nil]; 
     unitSelectViewController= [[UnitSelectViewController alloc] initWithNibName:@"UnitSelectViewController_iPhone" bundle:nil]; 
     self.navigationController = [[UINavigationController alloc] initWithRootViewController:converterViewController]; 
     self.navigationController.navigationBar.tintColor = [UIColor colorWithRed:0.0f green:0.48235297203063965f blue:0.63137257099151611f alpha:1]; 
     [self presentModalViewController:self.navigationController animated:YES]; 
    } else { 
     converterViewController = [[ConverterViewController alloc] initWithNibName:@"ConverterViewController_iPad" bundle:nil]; 
     unitSelectViewController= [[UnitSelectViewController alloc] initWithNibName:@"UnitSelectViewController_iPad" bundle:nil]; 
     UINavigationController *masterNavigationController = [[UINavigationController alloc] initWithRootViewController:unitSelectViewController]; 
     UINavigationController *detailNavigationController = [[UINavigationController alloc] initWithRootViewController:converterViewController]; 
     masterNavigationController.navigationBar.tintColor = [UIColor colorWithRed:0.0f green:0.48235297203063965f blue:0.63137257099151611f alpha:1]; 
     detailNavigationController.navigationBar.tintColor = [UIColor colorWithRed:0.0f green:0.48235297203063965f blue:0.63137257099151611f alpha:1]; 

     self.splitViewController = [[UISplitViewController alloc] init]; 

     self.splitViewController.delegate = converterViewController; 

     self.splitViewController.viewControllers = [NSArray arrayWithObjects:masterNavigationController, detailNavigationController, nil]; 
     [self presentModalViewController:self.splitViewController animated:YES]; // ERROR comes from here i think 
    } 

    unitSelectViewController.delegate = converterViewController; 
    converterViewController.unitSelectViewController = unitSelectViewController; 
} 

Answer 1

问题看起来明显。以下是从UISplitViewController文件复制：

"you must always install the view from a UISplitViewController object as the root view of your application’s window. [...] Split view controllers cannot be presented modally."

换句话说，你看到的是预期的行为。