UITabbarViewController代码重构

原始代码：

UIViewController *vc1 = [[UIViewController alloc] init];
    vc1.tabBarItem.title = @"首页";
    vc1.tabBarItem.image = [UIImage imageNamed:@"tabbar_home"];
    vc1.tabBarItem.selectedImage = [[UIImage imageNamed:@"tabbar_home_selected"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];//取消默认蓝色，按原始图片输出
    [vc1.tabBarItem setTitleTextAttributes:textAttrs forState:UIControlStateNormal];
    [vc1.tabBarItem setTitleTextAttributes:selectedTextAttrs forState:UIControlStateHighlighted];
    vc1.view.backgroundColor = randomColor;
    
    UIViewController *vc2 = [[UIViewController alloc] init];
    vc2.tabBarItem.title = @"消息";
    vc2.tabBarItem.image = [UIImage imageNamed:@"tabbar_message_center"];
    vc2.tabBarItem.selectedImage = [[UIImage imageNamed:@"tabbar_message_center_selected"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    [vc2.tabBarItem setTitleTextAttributes:textAttrs forState:UIControlStateNormal];
    [vc2.tabBarItem setTitleTextAttributes:selectedTextAttrs forState:UIControlStateHighlighted];
    vc2.view.backgroundColor = randomColor;
    
    UIViewController *vc3 = [[UIViewController alloc] init];
    vc3.tabBarItem.title = @"发现";
    vc3.tabBarItem.image = [UIImage imageNamed:@"tabbar_discover"];
    vc3.tabBarItem.selectedImage = [[UIImage imageNamed:@"tabbar_discover_selected"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    [vc3.tabBarItem setTitleTextAttributes:textAttrs forState:UIControlStateNormal];
    [vc3.tabBarItem setTitleTextAttributes:selectedTextAttrs forState:UIControlStateHighlighted];
    vc3.view.backgroundColor = randomColor;
    
    UIViewController *vc4 = [[UIViewController alloc] init];
    vc4.tabBarItem.title = @"我";
    vc4.tabBarItem.image = [UIImage imageNamed:@"tabbar_profile"];
    vc4.tabBarItem.selectedImage = [[UIImage imageNamed:@"tabbar_profile_selected"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    [vc4.tabBarItem setTitleTextAttributes:textAttrs forState:UIControlStateNormal];
    [vc4.tabBarItem setTitleTextAttributes:selectedTextAttrs forState:UIControlStateHighlighted];
    vc4.view.backgroundColor = randomColor;
    
    //tabBarVC.viewControllers = @[vc1,vc2];
    [tabBarVC addChildViewController:vc1];
    [tabBarVC addChildViewController:vc2];
    [tabBarVC addChildViewController:vc3];
    [tabBarVC addChildViewController:vc4];

重构之后

  HomeViewController *homeVC = [[HomeViewController alloc] init];
    [self addChildVC:homeVC title:NSLocalizedString(@"HomeTitle",@"HomeTitle") image:@"tabbar_home" selectedImage:@"tabbar_home_selected"];
    
    MessageCenterViewController *messageCenterVC = [[MessageCenterViewController alloc] init];
    [self addChildVC:messageCenterVC title:NSLocalizedString(@"MessageCenterTitle", @"MessageCenterTitle") image:@"tabbar_message_center" selectedImage:@"tabbar_message_center"];
    
    DiscoverViewController *discoverVC = [[DiscoverViewController alloc] init];
    [self addChildVC:discoverVC title:NSLocalizedString(@"DiscoverTitle", @"DiscoverTitle") image:@"tabbar_discover" selectedImage:@"tabbar_discover_selected"];
    
    ProfileViewController *profileVC = [[ProfileViewController alloc] init];
    [self addChildVC:profileVC title:NSLocalizedString(@"ProfileTitle",@"ProfileTitle") image:@"tabbar_profile" selectedImage:@"tabbar_profile_selected"];


/**
 *  设置子控制器
 *
 *  @param childVC       子控制器
 *  @param title         标题
 *  @param image         图片
 *  @param selectedImage 选中时的图片
 */
- (void)addChildVC:(UIViewController *)childVC title:(NSString *)title image:(NSString *)image selectedImage:(NSString *)selectedImage{
    
    NSMutableDictionary *textAttrs = [NSMutableDictionary dictionary];
    textAttrs[NSForegroundColorAttributeName] = RGBACOLOR(123.0, 123.0, 123.0, 1.0);
    NSMutableDictionary *selectedTextAttrs = [NSMutableDictionary dictionary];
    selectedTextAttrs[NSForegroundColorAttributeName] = [UIColor orangeColor];
    
    childVC.tabBarItem.title = title;
    childVC.tabBarItem.image = [UIImage imageNamed:image];
    childVC.tabBarItem.selectedImage = [[UIImage imageNamed:selectedImage] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    [childVC.tabBarItem setTitleTextAttributes:textAttrs forState:UIControlStateNormal];
    [childVC.tabBarItem setTitleTextAttributes:selectedTextAttrs forState:UIControlStateHighlighted];
    childVC.view.backgroundColor = randomColor;
}

注意点：不要传类，要传控制器。因为如果传递类，那么创建就要封装在方法内部，但是初始化方法是可能发生变化的，因此，应该在需要的时候创建控制器，这样更佳灵活，易于扩展。