新建一个子类

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface CCSplit : UISplitViewController
+(instancetype)share;
@end

NS_ASSUME_NONNULL_END

#import "CCSplit.h"

@interface CCSplit ()

@end

@implementation CCSplit

+(instancetype)share{
    static CCSplit *instance;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        instance=[[CCSplit alloc] init];
    });
    return instance;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

@end

在建一个左边的viewController 与右边的viewcontroller
左边用来控制，右边用来显示详细信息的
左边的操作,这样就可以实时的显示右边的viewcontroller了

//建一个新的，或者使用已有的来显示在右边
UIViewController *subView=[[CCRightViewController alloc] init];
subView.navigationItem.leftBarButtonItem=[CCSplit share].displayModeButtonItem;
        subView.navigationItem.leftItemsSupplementBackButton=YES;
        
[[CCSplit share] showDetailViewController:[[UINavigationController alloc] initWithRootViewController:subView] sender:nil];
[CCSplit share].preferredDisplayMode=UISplitViewControllerDisplayModeAllVisible;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window.rootViewController=self.splitVC;
    [self.window makeKeyAndVisible];
    return YES;
}
-(CCLeftViewController *)leftVC{
    if (!_leftVC) {
        _leftVC=[CCLeftViewController new];
    }
    return _leftVC;
}

-(CCRightViewController *)rightVC{
    if (!_rightVC) {
        _rightVC=[[CCRightViewController alloc] init];
    }
    return _rightVC;
}
-(CCSplit *)splitVC{
    if (!_splitVC) {
        _splitVC=[CCSplit share];
        _splitVC.preferredDisplayMode=UISplitViewControllerDisplayModeAllVisible;
        _splitVC.maximumPrimaryColumnWidth=100;
        _splitVC.viewControllers=@[self.leftVC,self.rightVC];
    
    }
    return _splitVC;
}