1>創建程序載入界面 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {     //1>創建窗口     self.window = [[UIWindowalloc] initWithFrame:[UIScreenmainScreen].bounds];     //2>設置窗口的根控制器     UITabBarController *tabBarController = [[UITabBarControlleralloc] init];     self.window.rootViewController = tabBarController;     //3>顯示窗口     [self.windowmakeKeyAndVisible];     returnYES; }     2>LaunchImage配置   LaunchImage.launchimage文件下的Contents.json文件中記錄了LaunchImage的詳細配置:     QQ20140703 1     3>取消APP圖標渲染   QQ20140704 1     4>程序加載時隱藏狀態欄   QQ20140704 2     在程序加載完成後如需恢復狀態欄顯示,可以在didFinishLaunchingWithOptions方法中調用[application setStatusBarHidden:NO]方法;       5>添加TabBar控制器及其子控制器   自定義一個TabBarViewController類繼承UITabBarController類用來創建自定義的TabBarView,並在該類中的viewDidLoad方法中創建子控制器   - (void)viewDidLoad {     [superviewDidLoad];     //添加子控制器     UIViewController *home = [[UIViewControlleralloc] init];     home.view.backgroundColor = [UIColorredColor];     home.tabBarItem.title = @"首頁";     home.tabBarItem.image = [UIImageimageNamed:@"tabbar_home"];     [home.tabBarItemsetSelectedImage:[UIImageimageNamed:@"tabbar_home_selected"]];     [selfaddChildViewController:home];     UIViewController *message = [[UIViewControlleralloc] init];     message.view.backgroundColor = [UIColororangeColor];     message.tabBarItem.title = @"消息";     message.tabBarItem.image = [UIImageimageNamed:@"tabbar_message_center"];     [message.tabBarItemsetSelectedImage:[UIImageimageNamed:@"tabbar_message_center_selected"]];     [selfaddChildViewController:message];     UIViewController *discover = [[UIViewControlleralloc] init];     discover.view.backgroundColor = [UIColorgreenColor];     discover.tabBarItem.title = @"發現";     discover.tabBarItem.image = [UIImage imageNamed:@"tabbar_discover"];     [discover.tabBarItemsetSelectedImage:[UIImageimageNamed:@"tabbar_discover_selected"]];     [selfaddChildViewController:discover];     UIViewController *profile = [[UIViewControlleralloc] init];     profile.view.backgroundColor = [UIColorblueColor];     profile.tabBarItem.title = @"我";     profile.tabBarItem.image = [UIImageimageNamed:@"tabbar_profile"];     [profile.tabBarItemsetSelectedImage:[UIImageimageNamed:@"tabbar_profile_selected"]];     [selfaddChildViewController:profile]; }   6>渲染圖片     在iOS7中，會對selectedImage的圖片再次渲染為藍色，要想顯示原圖，就必須要取消渲染；       取消渲染調用的方法：       selectedImage = [selectedImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];       7>優化添加子控制器代碼     將添加子控制器到TabBarViewController的代碼進行優化，建立如下方法：   - (void)addOneChildViewController:(UIViewController *)viewController withTitle:(NSString *)title imageName:(NSString *)imageName selectedImageName:(NSString *)selectedImageName {     viewController.view.backgroundColor = ZFRandomColor;     viewController.tabBarItem.title = title;     viewController.tabBarItem.image = [UIImage imageNamed:imageName]; UIImage *image = [UIImage imageNamed:selectedImageName]; if (iOS7) {         image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];     }     [viewController.tabBarItem setSelectedImage:image];     [self addChildViewController:viewController]; }     其中ZFRandomColor和iOS7為自定義宏,其宏定義在Prefix.pch文件下:   #ifdef __OBJC__     #import <UIKit/UIKit.h>     #import <Foundation/Foundation.h>     #import <CoreData/CoreData.h> #define ZFRandomColor [UIColor colorWithRed:arc4random_uniform(256)/255.0 green:arc4random_uniform(256)/255.0 blue:arc4random_uniform(256)/255.0 alpha:1.0] #define iOS7 [[UIDevice currentDevice].systemVersion doubleValue] >= 7.0 #endif     由於imageWithRenderingMode方法只在iOS7環境下有效,因此此處代碼需要添加條件判斷語句進行系統適配,通過獲取當前運行環境的系統版本來判斷是否編譯此方法;   8>圖片適配     為UIImage添加一個分類,用於image的系統適配:   @implementation UIImage (Extension) + (UIImage *)imageWithName:(NSString *)imageName { UIImage *image = nil; if (iOS7) { NSString *name = [imageName stringByAppendingString:@"_os7"];         image = [UIImage imageNamed:name];     } if (!image) {         image = [UIImage imageNamed:imageName];     } return image; } @end