storyboard问题

问题：
用Interface Builder为UITabBarController 设置selected image，运行起来后提示：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：
获取制定的tabbar实例，用代码修改
<pre><code>

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

  //storyboard每次都创建个新的实例对象，因此需要呈现它 否则不显示
  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>

参考：How to set selected images for UITabBarItem in UITabBarController