問題：
用Interface Builder為UITabBarController 設置selected image，運行起來后提示：Could not load the "(null)" image referenced from a nib in the bundle with identifier

Screen-Shot-2014-12-14-at-20.54.18.png

修改方法：
獲取制定的tabbar實例，用代碼修改
<pre><code>

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

  //storyboard每次都創建個新的實例對象，因此需要呈現它 否則不顯示
  UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"main" bundle:[NSBundle mainBundle]];
  UITabBarController * tabBarController = [storyboard instantiateViewControllerWithIdentifier:@"TabBarController"];
  self.window.rootViewController = tabBarController;

  NSArray *imageArray = @[@"ic_tabbar_home",@"ic_tabbar_oversea_red",@"ic_tabbar_faxian_red", @"ic_tabbar_shopping_cart", @"ic_tabbar_my"];
  int i = 0;
  NSArray *itemArray = tabBarController.tabBar.items;
  for (UITabBarItem *item in itemArray) {
  UIImage *image = [UIImage imageNamed:imageArray[i++]];
  item.selectedImage = image;
  }
  tabBarController.tabBar.tintColor = [UIColor redColor];

  return YES;
  }
  </code></pre>

參考：How to set selected images for UITabBarItem in UITabBarController