The First：StoryBoard导航

思想：

在Xcode中，程序运行顺序如下：Xib  —> 代码 —> StoryBoard（后者亲测，前者未测）

细分：

当AppDelegate没有程序入口时，StoryBord有入口时，系统从StoryBord中进入

当StoryBord和AppDelegate都有入口时，优先从AppDelegate进入

当既没有AppDelegate也没有StoryBrod，那么程序从默认的ViewController开始

---

第一种：Root+ViewControllers

思想：

self.window.rootViewController=_tabbar;

_tabbar.viewControllers=@[nav1, nav2];

图一：

图二：

全部代码：

#import"AppDelegate.h"

#import"ViewController.h"

#import"HomeViewController.h"

@interfaceAppDelegate()

@property(nonatomic,strong)UITabBarController*tabbar;

@property(nonatomic,strong)UINavigationController*NC;

@end

@implementationAppDelegate

- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {

//1、初始化Window

self.window=[[UIWindowalloc]initWithFrame:[UIScreenmainScreen].bounds];

//2、初始化NV

ViewController*VC = [[ViewControlleralloc]init];

VC.title=@"diyige";

VC.view.backgroundColor= [UIColorredColor];

HomeViewController*HomeVC = [[HomeViewControlleralloc]init];

HomeVC.title=@"dierge";

HomeVC.view.backgroundColor= [UIColorgrayColor];

UINavigationController*nav1 =[[UINavigationControlleralloc]initWithRootViewController:VC];

UINavigationController*nav2 =[[UINavigationControlleralloc]initWithRootViewController:HomeVC];

//3、UINavigationController——> UITabbarController

_tabbar=[[UITabBarControlleralloc]init];

_tabbar.viewControllers=@[nav1, nav2];

_tabbar.delegate=self;

//5、UITabBarController  ——> Window

self.window.rootViewController=_tabbar;

//6、Window  ——> makeKeyVisible

[self.windowmakeKeyAndVisible];

//7、添加默认状态

[selftabBarController:_tabbardidSelectViewController:nav1];

returnYES;

}

//UITabBarControllerDelegate协议

-(void)tabBarController:(UITabBarController*)tabBarController didSelectViewController:(UIViewController*)viewController{

if(0 == tabBarController.selectedIndex) {

viewController.title=@"dudu";

tabBarController.navigationItem.rightBarButtonItem=nil;

}

else{

viewController.title=@"xixi";

tabBarController.navigationItem.rightBarButtonItem=nil;

}

}

---

第二种：全部Root

思想：

self.window.rootViewController=_NC;

_NC=[[UINavigationControlleralloc]initWithRootViewController:_tabbar];

图一：

图二：

全部代码：

#import"AppDelegate.h"

#import"ViewController.h"

#import"HomeViewController.h"

@interfaceAppDelegate()

@property(nonatomic,strong)UITabBarController*tabbar;

@property(nonatomic,strong)UINavigationController*NC;

@end

@implementationAppDelegate

- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {

//1、初始化Window

self.window=[[UIWindowalloc]initWithFrame:[UIScreenmainScreen].bounds];

//2、初始化NV

ViewController*p1 = [[ViewControlleralloc]init];

HomeViewController*p2 = [[HomeViewControlleralloc]init];

p1.tabBarItem.title=@"p1";

p2.tabBarItem.title=@"p2";

//3、ViewController ——> UITabbarController

_tabbar=[[UITabBarControlleralloc]init];

_tabbar.viewControllers=@[p1,p2];

_tabbar.delegate=self;

//4、UINanigationController ——> UITabBarController

_NC=[[UINavigationControlleralloc]initWithRootViewController:_tabbar];

//5、UITabBarController  ——> Window

self.window.rootViewController=_NC;

//6、Window  ——> makeKeyVisible

[self.windowmakeKeyAndVisible];

//7、添加默认状态

[selftabBarController:_tabbardidSelectViewController:p1];

returnYES;

}

//UITabBarControllerDelegate协议

-(void)tabBarController:(UITabBarController*)tabBarController didSelectViewController:(UIViewController*)viewController{

if(0 == tabBarController.selectedIndex) {

tabBarController.title=@"dudu";

tabBarController.navigationItem.rightBarButtonItem=nil;

}

else{

tabBarController.title=@"xixi";

tabBarController.navigationItem.rightBarButtonItem=nil;

}

}

---

技巧：需要不止一个ViewController的请 command+c/v  —>  ViewController

提示：下次编辑  —> UILayoutContainerView / Xcode程序运行底层设计 / 两种导航点评