UITabBarController的使用

UITabBarController 是多页面视图控制器切换控制器

一、主要使用方法，即属性设置：

1、视图控制器集合：viewControllers

2、切换视图属性：tabbar

2-1、tabbar 背景颜色：backgroundColor

2-2、tabbar 背景图标：backgroundImage

2-3、tabbar 标题（选中，或非选中状态）：UITabBarItem，- (void)setTitleTextAttributes:(nullable NSDictionary<NSString *,id> *)attributes forState:(UIControlState)state

2-4、tabbar 图标（选中，或非选中状态）：UITabBarItem，- (void)setFinishedSelectedImage:(nullable UIImage *)selectedImage withFinishedUnselectedImage:(nullable UIImage *)unselectedImage

或进行 2-3、2-4 属性的统一设置 方法如：

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1. // 设置标题，未选中状态图标，选中状态图标  
2. UITabBarItem *barItem = [[UITabBarItem alloc] initWithTitle:title image:imageNormal selectedImage:imageSelected];  
3. xxxViewController.tabBarItem = barItem;  

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1. // 设置标题字体颜色  
2. [[UITabBarItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor blackColor]} forState:UIControlStateNormal];  
3. [[UITabBarItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor orangeColor]} forState:UIControlStateSelected];  

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1. // 设置标题字体大小  
2. [[UITabBarItem appearance] setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:8.0]} forState:UIControlStateNormal];  

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1. // 设置标题字体偏移  
2. [[UITabBarItem appearance] setTitlePositionAdjustment:UIOffsetMake(0.0, -8.0)];  

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1. // 设置图标选中时颜色  
2. [[UITabBar appearance] setTintColor:[UIColor redColor]];  

3、默认选中视图控制器：selectedIndex

     

二、使用注意事项：

1、设置视图控制器集合时，是 UINavigationController 导航栏控制器集合；

2、设置视图控制器集合时，通常小于等于 5 个 视图控制器，超过 5 个时系统默认生成一个 more 的控制器页面，用于操作多余的视图控制器

3、视图控制器导航栏标题设置时，注意使用：" self.navigationItem.title = @"xxx"; "，而不使用" self.title = @"xxx"; "，避免影响 UITabBarController 中 tabbar 标题的设置。

4、当要显示下一个视图控制器，且需要隐藏 tabbarController 控制器时，设置视图控制器的属性 hidesBottomBarWhenPushed 值为YES，如：

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1. UIViewController *nextVC = [[UIViewController alloc] init];  
2. nextVC.hidesBottomBarWhenPushed = YES;  
3. [self.navigationController pushViewController:nextVC animated:YES];  

5、第一次初始化时，会出现设置的 tabbar 图标颜色异常，设置属性 tintColor 与图标颜色一致后，则不会，如：

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1. [[UITabBar appearance] setTintColor:[UIColor redColor]];  

6、tabbar 标题设置后出现偏移情况，即靠近底端，可通过设置属性 titlePositionAdjustment 进行调整，如：

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1. [[UITabBarItem appearance] setTitlePositionAdjustment:UIOffsetMake(0.0, -8.0)];  

7、设置 badgeValue 标识属性时，特别是在 viewController 中设置时，注意使用方法为" self.navigationController.tabBarItem.badgeValue = @"0"; "，而不是" self.tabBarItem.badgeValue = @"0"; "，否则无效，如：

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1. - (void)viewWillAppear:(BOOL)animated  
2. {  
3.         NSInteger index = arc4random() % 2;  
4.         if (0 == index)  
5.         {  
6.             // self.tabBarItem.badgeValue = nil; // 无效  
7.             self.navigationController.tabBarItem.badgeValue = nil;  
8.         }  
9.         else  
10.         {  
11.             index = arc4random() % 100 + 1;  
12.             // self.tabBarItem.badgeValue = [NSString stringWithFormat:@"%ld", index]; // 无效  
13.             self.navigationController.tabBarItem.badgeValue = [NSString stringWithFormat:@"%ld", index];  
14.         }  
15. }  

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1. // 1 创建视图控制器  
2. MessageViewController *messageVC = [[MessageViewController alloc] init];  
3. UINavigationController *messageNav = [[UINavigationController alloc] initWithRootViewController:messageVC];  
4. ContacterViewController *contacterVC = [[ContacterViewController alloc] init];  
5. UINavigationController *contacterNav = [[UINavigationController alloc] initWithRootViewController:contacterVC];  
6. DynamicViewController *dynamicVC = [[DynamicViewController alloc] init];  
7. UINavigationController *dynamicNav = [[UINavigationController alloc] initWithRootViewController:dynamicVC];  
8. // 视图控制器数组  
9. NSArray *controllerArray = @[messageNav, contacterNav, dynamicNav];  

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1. // 2 创建tabbarController控制器  
2. UITabBarController *tabbarController = [[UITabBarController alloc] init];  
3. // 属性设置  
4. // 设置默认被选中视图控制器  
5. tabbarController.selectedIndex = 0;  
6. // 设置切换视图 tabBar 属性  
7. // 1 打开用户交互  
8. tabbarController.tabBar.userInteractionEnabled = YES;  
9. // 2 设置背景颜色  
10. tabbarController.tabBar.backgroundColor = [UIColor whiteColor];  
11. // 3 设置背景图片  
12. tabbarController.tabBar.backgroundImage = [UIImage imageNamed:@"background"];  
13. // 选中时的背景图片  
14. tabbarController.tabBar.selectionIndicatorImage = [UIImage imageNamed:@"backgroundSelected"];  
15. // 4 设置按钮标题、常规图标、选中时图标  
16. NSArray *titleArray = @[@"消息", @"联系人", @"动态"];  
17. NSArray *imageNArray = @[[UIImage imageNamed:@"messageNormal"], [UIImage imageNamed:@"contacterNormal"], [UIImage imageNamed:@"dynamicNormal"]];  
18. NSArray *imageSAarray = @[[UIImage imageNamed:@"messageSelected"], [UIImage imageNamed:@"contacterSelected"], [UIImage imageNamed:@"dynamicSelected"]];  

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1. /**************************************/  
2.       
3. // 更多视图控制器的情况  
4. UIViewController *vc4 = [[UIViewController alloc] init];  
5. vc4.title = @"vc4";  
6. UINavigationController *nav4 = [[UINavigationController alloc] initWithRootViewController:vc4];  
7. UIViewController *vc5 = [[UIViewController alloc] init];  
8. vc5.title = @"vc5";  
9. UINavigationController *nav5 = [[UINavigationController alloc] initWithRootViewController:vc5];  
10. UIViewController *vc6 = [[UIViewController alloc] init];  
11. vc6.title = @"vc6";  
12. UINavigationController *nav6 = [[UINavigationController alloc] initWithRootViewController:vc6];  
13. UIViewController *vc7 = [[UIViewController alloc] init];  
14. vc7.title = @"vc7";  
15. UINavigationController *nav7 = [[UINavigationController alloc] initWithRootViewController:vc7];  
16. UIViewController *vc8 = [[UIViewController alloc] init];  
17. vc8.title = @"vc8";  
18. UINavigationController *nav8 = [[UINavigationController alloc] initWithRootViewController:vc8];  
19. // 视图控制器数组  
20. NSArray *controllerArray = @[messageNav, contacterNav, dynamicNav, nav4, nav5, nav6, nav7, nav8];  
21. NSArray *titleArray = @[@"消息", @"联系人", @"动态", @"nav4", @"nav5", @"nav6", @"nav7", @"nav8"];  
22. NSArray *imageNArray = @[[UIImage imageNamed:@"messageNormal"], [UIImage imageNamed:@"contacterNormal"], [UIImage imageNamed:@"dynamicNormal"], [UIImage imageNamed:@"dynamicNormal"], [UIImage imageNamed:@"dynamicNormal"], [UIImage imageNamed:@"dynamicNormal"], [UIImage imageNamed:@"dynamicNormal"], [UIImage imageNamed:@"dynamicNormal"]];  
23. NSArray *imageSAarray = @[[UIImage imageNamed:@"messageSelected"], [UIImage imageNamed:@"contacterSelected"], [UIImage imageNamed:@"dynamicSelected"], [UIImage imageNamed:@"contacterSelected"], [UIImage imageNamed:@"contacterSelected"], [UIImage imageNamed:@"contacterSelected"], [UIImage imageNamed:@"contacterSelected"], [UIImage imageNamed:@"contacterSelected"]];  
24.       
25. /**************************************/  

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1. // 5 设置视图控制器  
2. tabbarController.viewControllers = controllerArray;  

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1. // 6 设置 tabbar 标题、图标  
2. // 方法1  
3. NSArray *items = tabbarController.tabBar.items;  
4. NSInteger count = items.count;  
5. for (int index = 0; index < count; index++)  
6. {  
7.         NSString *title = titleArray[index];  
8.         UIImage *imageN = imageNArray[index];  
9.         UIImage *imageS = imageSAarray[index];  
10.           
11.         UITabBarItem *aItem = [items objectAtIndex:index];  
12.         // 标题设置（字体偏移、字体大小、字体颜色）  
13.         aItem.title = title;  
14. //        aItem.titlePositionAdjustment = UIOffsetMake(0.0, -10.0);  
15. //        [aItem setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:8.0]} forState:UIControlStateNormal];  
16. //        [aItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]} forState:UIControlStateNormal];  
17. //        [aItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor redColor]} forState:UIControlStateSelected];  
18.         // 图标设置  
19. //        [aItem setFinishedSelectedImage:imageS withFinishedUnselectedImage:imageN];  
20.         aItem.image = imageN;  
21.         aItem.selectedImage = imageS;  
22. }  

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1. // 方法2  
2. UITabBarItem *messageBarItem = [[UITabBarItem alloc] initWithTitle:titleArray[0] image:imageNArray[0] selectedImage:imageSAarray[0]];  
3. [messageBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]} forState:UIControlStateNormal];  
4. [messageBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor redColor]} forState:UIControlStateSelected];  
5. messageBarItem.badgeValue = @"10";  
6. messageVC.tabBarItem = messageBarItem;  
7. UITabBarItem *contacterBarItem = [[UITabBarItem alloc] initWithTitle:titleArray[1] image:imageNArray[1] selectedImage:imageSAarray[1]];  
8. [contacterBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]} forState:UIControlStateNormal];  
9. [contacterBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor redColor]} forState:UIControlStateSelected];  
10. contacterBarItem.badgeValue = @"3";  
11. contacterVC.tabBarItem = contacterBarItem;  
12. UITabBarItem *dynamicBarItem = [[UITabBarItem alloc] initWithTitle:titleArray[2] image:imageNArray[2] selectedImage:imageSAarray[2]];  
13. [dynamicBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]} forState:UIControlStateNormal];  
14. [dynamicBarItem setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor redColor]} forState:UIControlStateSelected];  
15. dynamicBarItem.badgeValue = @"21";  
16. dynamicVC.tabBarItem = dynamicBarItem;  

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1. // 设置字体颜色  
2. [[UITabBarItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor blackColor]} forState:UIControlStateNormal];  
3. [[UITabBarItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor orangeColor]} forState:UIControlStateSelected];  
4. // 设置字体大小  
5. [[UITabBarItem appearance] setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:8.0]} forState:UIControlStateNormal];  
6. // 设置字体偏移  
7. [[UITabBarItem appearance] setTitlePositionAdjustment:UIOffsetMake(0.0, -8.0)];  
8. // 设置图标选中时颜色  
9. [[UITabBar appearance] setTintColor:[UIColor redColor]];