自定义tabBar，创建一个类继承UITabBar

1>写这篇文章的意义在于，之前我一直用继承UIview的方式自定义UITabBar，这又很多弊端，比如图片的拉伸都需要自己设置。今天用的是继承UITabBar的方式，这样图片以及文字就可以自己管控

首先是在TabBarController里设置子控制器的属性，并加载自定义的UITabBar

- (void)viewDidLoad {
    [super viewDidLoad];
    
    /**** 设置所有UITabBarItem的文字属性 ****/
    [self setupItemTitleTextAttributes];
    
    /**** 添加子控制器 ****/
    [self setupChildViewControllers];
    
    /**** 更换TabBar ****/
    [self setupTabBar];
}

/**
 *  设置所有UITabBarItem的文字属性
 */
- (void)setupItemTitleTextAttributes
{
    UITabBarItem *item = [UITabBarItem appearance];
    // 普通状态下的文字属性
    NSMutableDictionary *normalAttrs = [NSMutableDictionary dictionary];
    normalAttrs[NSFontAttributeName] = [UIFont systemFontOfSize:14];
    normalAttrs[NSForegroundColorAttributeName] = [UIColor grayColor];
    [item setTitleTextAttributes:normalAttrs forState:UIControlStateNormal];
    // 选中状态下的文字属性
    NSMutableDictionary *selectedAttrs = [NSMutableDictionary dictionary];
    selectedAttrs[NSForegroundColorAttributeName] = [UIColor darkGrayColor];
    [item setTitleTextAttributes:normalAttrs forState:UIControlStateSelected];
}

/**
 *  添加子控制器
 */
- (void)setupChildViewControllers
{
    [self setupOneChildViewController:[[XMGNavigationController alloc] initWithRootViewController:[[XMGEssenceViewController alloc] init]] title:@"精华" image:@"tabBar_essence_icon" selectedImage:@"tabBar_essence_click_icon"];
    
    [self setupOneChildViewController:[[XMGNavigationController alloc] initWithRootViewController:[[XMGNewViewController alloc] init]] title:@"新帖" image:@"tabBar_new_icon" selectedImage:@"tabBar_new_click_icon"];
    
    [self setupOneChildViewController:[[XMGNavigationController alloc] initWithRootViewController:[[XMGFollowViewController alloc] init]] title:@"关注" image:@"tabBar_friendTrends_icon" selectedImage:@"tabBar_friendTrends_click_icon"];
    
    [self setupOneChildViewController:[[XMGNavigationController alloc] initWithRootViewController:[[XMGMeViewController alloc] init]] title:@"我" image:@"tabBar_me_icon" selectedImage:@"tabBar_me_click_icon"];
}

/**
 *  初始化一个子控制器
 *
 *  @param vc            子控制器
 *  @param title         标题
 *  @param image         图标
 *  @param selectedImage 选中的图标
 */
- (void)setupOneChildViewController:(UIViewController *)vc title:(NSString *)title image:(NSString *)image selectedImage:(NSString *)selectedImage
{
    vc.tabBarItem.title = title;
    if (image.length) { // 图片名有具体值
        vc.tabBarItem.image = [UIImage imageNamed:image];
        vc.tabBarItem.selectedImage = [UIImage imageNamed:selectedImage];
    }
    [self addChildViewController:vc];
}

/**
 *  更换TabBar
 */
- (void)setupTabBar
{
    [self setValue:[[XMGTabBar alloc] init] forKeyPath:@"tabBar"];
}

#pragma mark - 懒加载
/** 发布按钮 */
- (UIButton *)publishButton
{
    if (!_publishButton) {
        UIButton *publishButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [publishButton setImage:[UIImage imageNamed:@"tabBar_publish_icon"] forState:UIControlStateNormal];
        [publishButton setImage:[UIImage imageNamed:@"tabBar_publish_click_icon"] forState:UIControlStateHighlighted];
        [publishButton addTarget:self action:@selector(publishClick) forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:publishButton];
        _publishButton = publishButton;
    }
    return _publishButton;
}

#pragma mark - 初始化
- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        self.backgroundImage = [UIImage imageNamed:@"tabbar-light"];
    }
    return self;
}

/**
 *  布局子控件
 */
- (void)layoutSubviews
{
    [super layoutSubviews];
    /**** 按钮的尺寸 ****/
    CGFloat buttonW = self.xmg_width / 5;
    CGFloat buttonH = self.xmg_height;
    
    /**** 设置所有UITabBarButton的frame ****/
    CGFloat tabBarButtonY = 0;
    // 按钮索引
    int tabBarButtonIndex = 0;
    
    for (UIView *subview in self.subviews) {
        // 过滤掉非UITabBarButton
        if (subview.class != NSClassFromString(@"UITabBarButton")) continue;
        
        // 设置frame
        CGFloat tabBarButtonX = tabBarButtonIndex * buttonW;
        if (tabBarButtonIndex >= 2) { // 右边的2个UITabBarButton
            tabBarButtonX += buttonW;
        }
        subview.frame = CGRectMake(tabBarButtonX, tabBarButtonY, buttonW, buttonH);
        
        // 增加索引
        tabBarButtonIndex++;
    }
    
    /**** 设置中间的发布按钮的frame ****/
    self.publishButton.xmg_width = buttonW;
    self.publishButton.xmg_height = buttonH;
    self.publishButton.xmg_centerX = self.xmg_width * 0.5;
    self.publishButton.xmg_centerY = self.xmg_height * 0.5;
}

#pragma mark - 监听
- (void)publishClick
{
    XMGLogFunc
}

非常简单尤其是涉及到这种tabBar的时候最有效

92ACEF527103FB470C45E27DF4A4D0E6.png