UIKit - UITabBarController

设置 TabBarItem 的文字属性

    NSMutableDictionary *normalAttrs = [NSMutableDictionary dictionary];
    normalAttrs[NSFontAttributeName] = [UIFont systemFontOfSize:12];
    normalAttrs[NSForegroundColorAttributeName] = [UIColor grayColor];
    [self.tabBarItem setTitleTextAttributes:normalAttrs forState:UIControlStateNormal];\

替换 UITabBarController 的 TabBar

    [self setValue: [[XMGTabBar alloc]init ] forKeyPath:”tabBar”];

设置 TabBarItem 文字偏移

[[UITabBarItem appearance] setTitlePositionAdjustment:UIOffsetMake(0, -3)];

hidesBottomBarWhenPushed Bug

// 如果掉了 self.tabBarcontroller.tabBar.hidden = YES , 且在 push 出新的控制器时设置了 hidesBottomBarWhenPushed = YES,
// pop 回来之后 tabBar 会显示，下面👇重写方法防止该情况发生
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
    if (viewController.hidesBottomBarWhenPushed && self.tabBarController) {
        if (self.tabBarController.tabBar.hidden) {
            viewController.hidesBottomBarWhenPushed = NO;
        }
    }
    [super pushViewController:viewController animated:animated];
}