如何以编程方式添加UITabBarItem？

Question

在我的应用程序中，我已经在“Storyborad”中添加了UITabBarController。但现在我想以编程方式添加UITabBarItem。假设有5个按钮，每当用户单击该按钮时，就会调用我的UITabBarController。"tabbar"中总共有5个选项卡。例如：

选项卡名称：item1、item2、item3、item4、item5。 按钮名称：item1、item2、item3、item4、item5。

假设用户单击item1按钮，则会调用UITabBarcontroller。现在用户不应该能够在“tabbarcontroller”中看到item1选项卡，而应该能够看到重置的“tabBaritem”。

有谁能帮我解决这个问题吗？ 如何以编程方式实现？

谢谢。

Nilesh J

- Nilesh .S. Joshi

Answer 1

UITabBarItem * itemNew = [[UITabBarItem alloc] initWithTitle:@"Page 1"
                                                     image:[UIImage imageNamed:@"page1_image_normal"]
                                             selectedImage:[UIImage imageNamed:@"page1_image_selected"]];

获取已有的tabBarItems

NSMutableArray *tbItems = [NSMutableArray arrayWithArray:[self.tabBar items]];
//Add your new tabBarItem
[tbItems addObject:itemNew];

//Set your tabBar items to the new array
[self.tabBar setItems:tbItems];

Swift 4

if var controllers = tabBarController?.viewControllers {
   let tabItem = UITabBarItem(title: "Item \(controllers.count)", image: nil, selectedImage: nil)
   let vc = UIViewController() // your new view controller
   vc.tabBarItem = tabItem
   controllers.append(vc) // or insert at index up to you
   tabBarController?.setViewControllers(controllers, animated: true)
}

- Pancho

---

尝试在iOS12上运行时出现了新错误，Terminating app due to uncaught exception 'NSInternalInconsistencyException'，reason: 'Directly modifying a tab bar managed by a tab bar controller is not allowed.' - Albert Renshaw

@AlbertRenshaw 刚刚添加了一个适用于 Swift 4 的代码片段。 - Pancho

Answer 2

要调用tabBar的单击事件，您需要执行以下操作：

在UITabBarDelegate上调用delegate方法并实现它们的方法：

- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item {
    //self.tabBarItem.title = @"Title";
}

- Abhishek Verma

Answer 3

这是用于自定义选项卡控制器的。在此代码中，您可以为选项卡按钮提供图像，并且当您单击一个按钮时，该按钮将根据您的图像进行更改。

设置UITabBarControllerDelegate的委托方法

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    [self creationTabBar];
    [self.window makeKeyAndVisible];
    return YES;
}

-(void)creationTabBar
{
UINavigationController *myNavigationController;

// Create initialized instance of UITabBarController

UITabBarController *tabBarController = [[UITabBarController alloc] init];

tabBarController.view.frame = CGRectMake(0, 0, self.window.bounds.size.width, self.window.bounds.size.height);

// Create initialized instance of NSMutableArray to hold our UINavigationControllers

NSMutableArray *tabs = [[NSMutableArray alloc] init];

World_ViewController *WorldScreen;
Home_ViewController *HomeScreen;
Favourite_ViewController *FavouriteScreen;
Rank_ViewController *RankScreen;
Setting_ViewController *SettingScreen;


UILabel *item1, *item2, *item3, *item4, *item5;

// Create first UIViewController

WorldScreen = [[World_ViewController alloc] initWithNibName:@"World_ViewController" bundle:nil];
HomeScreen = [[Home_ViewController alloc] initWithNibName:@"Home_ViewController" bundle:nil];
FavouriteScreen= [[Favourite_ViewController alloc] initWithNibName:@"Favourite_ViewController" bundle:nil];
RankScreen = [[Rank_ViewController alloc] initWithNibName:@"Rank_ViewController" bundle:nil];
SettingScreen = [[Setting_ViewController alloc] initWithNibName:@"Setting_ViewController" bundle:nil];

myNavigationController = [[UINavigationController alloc] initWithRootViewController:self.viewController];

item1 = [[UILabel alloc] initWithFrame:CGRectMake(0, 430, 64, 50)];
item2 = [[UILabel alloc] initWithFrame:CGRectMake(64, 430, 64, 50)];
item3 = [[UILabel alloc] initWithFrame:CGRectMake(128, 430, 64, 50)];
item4 = [[UILabel alloc] initWithFrame:CGRectMake(195, 430, 64, 50)];
item5 = [[UILabel alloc] initWithFrame:CGRectMake(256, 430, 64, 50)];


myNavigationController = [[UINavigationController alloc] initWithRootViewController:HomeScreen];
[myNavigationController setNavigationBarHidden:YES];
[tabs addObject:myNavigationController];

myNavigationController = [[UINavigationController alloc] initWithRootViewController:WorldScreen];
[myNavigationController setNavigationBarHidden:YES];
[tabs addObject:myNavigationController];

myNavigationController = [[UINavigationController alloc] initWithRootViewController:FavouriteScreen];
[myNavigationController setNavigationBarHidden:YES];
[tabs addObject:myNavigationController];

myNavigationController = [[UINavigationController alloc] initWithRootViewController:RankScreen];
[myNavigationController setNavigationBarHidden:YES];
[tabs addObject:myNavigationController];

myNavigationController = [[UINavigationController alloc] initWithRootViewController:SettingScreen];
[myNavigationController setNavigationBarHidden:YES];
[tabs addObject:myNavigationController];


[[UITabBar appearance] setBackgroundImage:[UIImage imageNamed:@"tabbar.png"]];
[tabBarController setViewControllers:tabs];
[tabBarController setDelegate:self];

[item1 setText:@"item1"];
[item1 setBackgroundColor:[UIColor grayColor]];
[tabBarController.view addSubview:item1];
item1.tag = 101;

[item2 setText:@"item2"];
[item2 setBackgroundColor:[UIColor grayColor]];
[tabBarController.view addSubview:item2];
item2.tag = 102;

[item3 setText:@"item3"];
[item3 setBackgroundColor:[UIColor grayColor]];
[tabBarController.view addSubview:item3];
item3.tag = 103;

[item4 setText:@"item4"];
[item4 setBackgroundColor:[UIColor grayColor]];
[tabBarController.view addSubview:item4];
item4.tag = 104;

[item5 setText:@"item5"];
[item5 setBackgroundColor:[UIColor grayColor]];
[tabBarController.view addSubview:item5];
item5.tag = 105;

[self.window setRootViewController:self.viewController];
}
- (void)tabBarController:(UITabBarController *)tabBarControllerref didSelectViewController:(UIViewController *)viewController
{
UILabel *item1 = (UILabel*)[tabBarControllerref.view viewWithTag:101];
UILabel *item2 = (UILabel*)[tabBarControllerref.view viewWithTag:102];
UILabel *item3 = (UILabel*)[tabBarControllerref.view viewWithTag:103];
UILabel *item4 = (UILabel*)[tabBarControllerref.view viewWithTag:104];
UILabel *item5 = (UILabel*)[tabBarControllerref.view viewWithTag:105];

[item1 setFrame: CGRectMake(0, 430, 64, 50)];
[item2 setFrame: CGRectMake(64, 430, 64, 50)];
[item3 setFrame: CGRectMake(128, 430, 64, 50)];
[item4 setFrame: CGRectMake(195, 430, 64, 50)];
[item5 setFrame: CGRectMake(256, 430, 64, 50)];

if([tabBarControllerref selectedIndex] == 0)
{
    [item1 setTextColor:[UIColor redColor]];
    [item2 setTextColor:[UIColor greenColor]];
    [item3 setTextColor:[UIColor greenColor]];
    [item4 setTextColor:[UIColor greenColor]];
    [item5 setTextColor:[UIColor greenColor]];
}
else if ([tabBarControllerref selectedIndex] == 1)
{
    [item1 setTextColor:[UIColor greenColor]];
    [item2 setTextColor:[UIColor redColor]];
    [item3 setTextColor:[UIColor greenColor]];
    [item4 setTextColor:[UIColor greenColor]];
    [item5 setTextColor:[UIColor greenColor]];
}
else if ([tabBarControllerref selectedIndex] == 2)
{
    [item1 setTextColor:[UIColor greenColor]];
    [item2 setTextColor:[UIColor greenColor]];
    [item3 setTextColor:[UIColor redColor]];
    [item4 setTextColor:[UIColor greenColor]];
    [item5 setTextColor:[UIColor greenColor]];
}
else if ([tabBarControllerref selectedIndex] == 3)
{
    [item1 setTextColor:[UIColor greenColor]];
    [item2 setTextColor:[UIColor greenColor]];
    [item3 setTextColor:[UIColor greenColor]];
    [item4 setTextColor:[UIColor redColor]];
    [item5 setTextColor:[UIColor greenColor]];
}
else if ([tabBarControllerref selectedIndex] == 4)
{
    [item1 setTextColor:[UIColor greenColor]];
    [item2 setTextColor:[UIColor greenColor]];
    [item3 setTextColor:[UIColor greenColor]];
    [item4 setTextColor:[UIColor greenColor]];
    [item5 setTextColor:[UIColor redColor]];
}

}

- Soumya Ranjan