iOS 开发自定义 UITabBarController 完整代码 (OC)

以下是一个简单的自定义 UITabBarController 的完整代码示例：

AppDelegate.h 文件：

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

AppDelegate.m 文件：

#import "AppDelegate.h"
#import "CustomTabBarController.h"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    
    // 创建自定义的 UITabBarController
    CustomTabBarController *tabBarController = [[CustomTabBarController alloc] init];
    
    // 设置根视图控制器为自定义的 UITabBarController
    self.window.rootViewController = tabBarController;
    
    [self.window makeKeyAndVisible];
    return YES;
}

@end

CustomTabBarController.h 文件：

#import <UIKit/UIKit.h>

@interface CustomTabBarController : UITabBarController

@end

CustomTabBarController.m 文件：

#import "CustomTabBarController.h"
#import "CustomTabBar.h"

@interface CustomTabBarController () <CustomTabBarDelegate>

@end

@implementation CustomTabBarController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // 创建自定义的标签栏
    CustomTabBar *customTabBar = [[CustomTabBar alloc] init];
    customTabBar.delegate = self;
    
    // 替换系统的标签栏
    [self setValue:customTabBar forKey:'tabBar'];
    
    // 创建并添加子视图控制器
    UIViewController *viewController1 = [[UIViewController alloc] init];
    UIViewController *viewController2 = [[UIViewController alloc] init];
    UIViewController *viewController3 = [[UIViewController alloc] init];
    
    viewController1.tabBarItem.title = 'Tab 1';
    viewController1.tabBarItem.image = [UIImage imageNamed:'tab1'];
    
    viewController2.tabBarItem.title = 'Tab 2';
    viewController2.tabBarItem.image = [UIImage imageNamed:'tab2'];
    
    viewController3.tabBarItem.title = 'Tab 3';
    viewController3.tabBarItem.image = [UIImage imageNamed:'tab3'];
    
    self.viewControllers = @[viewController1, viewController2, viewController3];
}

#pragma mark - CustomTabBarDelegate

- (void)tabBar:(CustomTabBar *)tabBar didSelectItemAtIndex:(NSInteger)index {
    self.selectedIndex = index;
}

@end

CustomTabBar.h 文件：

#import <UIKit/UIKit.h>

@protocol CustomTabBarDelegate;

@interface CustomTabBar : UITabBar

@property (nonatomic, weak) id<CustomTabBarDelegate> delegate;

@end

@protocol CustomTabBarDelegate <NSObject>

- (void)tabBar:(CustomTabBar *)tabBar didSelectItemAtIndex:(NSInteger)index;

@end

CustomTabBar.m 文件：

#import "CustomTabBar.h"

@implementation CustomTabBar

- (void)layoutSubviews {
    [super layoutSubviews];
    
    // 设置标签栏的 frame
    CGFloat tabBarButtonWidth = self.bounds.size.width / self.items.count;
    CGFloat tabBarButtonHeight = self.bounds.size.height;
    CGFloat tabBarButtonY = 0;

    for (int index = 0; index < self.items.count; index++) {
        CGFloat tabBarButtonX = index * tabBarButtonWidth;
        UIButton *tabBarButton = self.subviews[index];
        tabBarButton.frame = CGRectMake(tabBarButtonX, tabBarButtonY, tabBarButtonWidth, tabBarButtonHeight);
        tabBarButton.tag = index;
        [tabBarButton addTarget:self action:@selector(tabBarButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
    }
}

- (void)tabBarButtonClicked:(UIButton *)sender {
    if ([self.delegate respondsToSelector:@selector(tabBar:didSelectItemAtIndex:)]) {
        [self.delegate tabBar:self didSelectItemAtIndex:sender.tag];
    }
}

@end

此代码示例创建了一个自定义的 UITabBarController，并使用自定义的标签栏替换了系统的标签栏。自定义标签栏使用 UIButton 来表示每个标签按钮，并在点击按钮时触发代理方法通知 UITabBarController 切换选中的子视图控制器。