关于根视图

就是我原本是想先进入登录界面(原先的根视图是登录界面)，但自从用了网上看到的一直抽屉视图后，它发的代码要指明根视图为mmDrawerController(MMDrawerController的一个对象)，所以运行后，就直接调到这个中心视图界面了(但我本意是先进入登录界面，账号密码通过后才进入这个中心界面)，代码如下:
#import "AppDelegate.h"
#import "MMDrawerController.h"
#import "AFNetworking.h"
#import "MainViewController2.h"//中
#import "ModelViewController.h"//左
#import "ManageViewController.h"//右
#import "MainnavViewController.h"//导航栏
@interface AppDelegate (){
   
    ModelViewController *nv_left;
    MainViewController2 *nv_center;
    ManageViewController *nv_right;
    MMDrawerController *mmDrawerController;
  

}

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   //左右中三个视图控制器
    nv_right=[[ManageViewController alloc]init];
    nv_center=[[MainViewController2 alloc]init];
    nv_left=[[ModelViewController alloc]init];
   
    //导航栏控制器
    MainnavViewController *rightNavVc=[[MainnavViewController alloc]initWithRootViewController:nv_right];
    MainnavViewController *centerNavVc=[[MainnavViewController alloc]initWithRootViewController:nv_center];
    MainnavViewController *leftNavVc=[[MainnavViewController alloc]initWithRootViewController:nv_left];
   
    //抽屉控制器
    mmDrawerController=[[MMDrawerController alloc]initWithCenterViewController:centerNavVc leftDrawerViewController:leftNavVc rightDrawerViewController:rightNavVc];
   
    //关闭模式手势
mmDrawerController.closeDrawerGestureModeMask=MMCloseDrawerGestureModeAll;
   
    //打开模式手势
mmDrawerController.openDrawerGestureModeMask=MMOpenDrawerGestureModeAll;
   
    //抽屉控制器的最长宽度
    mmDrawerController.maximumLeftDrawerWidth=200;
   
    [self.window makeKeyAndVisible];
    self.window.rootViewController=mmDrawerController;
有什么解决办法吗?