讓TabBarItem 顯示出我們設置的圖片的真實樣子，需要看以下設置方法在AppDelegate.h中，拿到所有的item然后統一設置成自定義的圖片分別是選中和未選中，針對ios7以后
_tabBarController = [[UITabBarController alloc]init];
[_tabBarController setViewControllers:@[recNav,feedNav,postNav,loginNav]];
// 拿到 TabBar 在拿到想應的item
UITabBar *tabBar = _tabBarController.tabBar;
UITabBarItem *item0 = [tabBar.items objectAtIndex:0];
UITabBarItem *item1 = [tabBar.items objectAtIndex:1];
UITabBarItem *item2 = [tabBar.items objectAtIndex:2];
UITabBarItem *item3 = [tabBar.items objectAtIndex:3];
// 對item設置相應地圖片
item0.selectedImage = [[UIImage imageNamed:@"recognize-1"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];;
item0.image = [[UIImage imageNamed:@"recognize"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
item1.selectedImage = [[UIImage imageNamed:@"life-1"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];;
item1.image = [[UIImage imageNamed:@"life"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
item2.selectedImage = [[UIImage imageNamed:@"edit-1"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];;
item2.image = [[UIImage imageNamed:@"edit"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
item3.selectedImage = [[UIImage imageNamed:@"setting-1"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];;
item3.image = [[UIImage imageNamed:@"setting"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
通過以上代碼設置就把4個item的圖片設置好了當然也可以分別在對應的controller中進行相應地設置，不過建議統一設置修改起來比較省事，如果需要在item點擊有很炫的動畫或是其他樣式，那就需要高度自定義才能實現
另一種思路
IOS8以前使用的是：
UITabBarItem *photoItem = [[UITabBarItem alloc] initWithTitle:@"首頁" image:[UIImage imageNamed:@"app2"] tag:0];
photo.tabBarItem = photoItem;
[photo.tabBarItem setFinishedSelectedImage:[UIImage imageNamed:@"app1"] withFinishedUnselectedImage:[UIImage imageNamed:@"app2"]];
[photoItem release];
使用新的API方法來初始化tabBarItem
?- (instancetype)initWithTitle:(NSString *)title image:(UIImage *)image selectedImage:(UIImage *)selectedImage
同時對使用的UIImage設置一下UIImageRenderingMode，使用UIImageRenderingModeAlwaysOriginal
用例：
?UIImage * normalImage = [[UIImage imageNamed:@"nor.png"]? imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIImage * selectImage = [[UIImage imageNamed:@"select.png"]? imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
?UITabBarItem * tabBarItem = [[UITabBarItem alloc]initWithTitle:@"" image:normalImage selectedImage:selectImage];
