TvOS UITabBarController 检测标签栏 shown/hidden

Question

有没有办法检测到UITabBarController 的标签栏会出现或消失？我想与 shows/hides 标签栏的动画同时制作动画。

我还没有找到检测此事件的任何方法。标签栏的属性 "hidden" 不是一个选项，因为它会在动画结束后更改其值

Answer 1

解决方案是使用视图控制器中的方法 didUpdateFocusInContext:withAnimationCoordinator：使用此代码：

static NSString *kUITabBarButtonClassName = @"UITabBarButton";

NSString *prevFocusViewClassName = NSStringFromClass([context.previouslyFocusedView class]);
    NSString *nextFocusedView = NSStringFromClass([context.nextFocusedView class]);

    // The tabbar is going to disappear
    if ([prevFocusViewClassName isEqualToString:kUITabBarButtonClassName] &&
        ![nextFocusedView isEqualToString:kUITabBarButtonClassName]) {
        [self.view layoutIfNeeded];
        self.constraintScrollViewCenterY.constant -= self.tabBarController.tabBar.frame.size.height;

        [coordinator addCoordinatedAnimations:^{
            [self.view layoutIfNeeded];
        } completion:nil];
    // The tabbar is going to appear
    } else if (![prevFocusViewClassName isEqualToString:kUITabBarButtonClassName] &&
               [nextFocusedView isEqualToString:kUITabBarButtonClassName]) {
        [self.view layoutIfNeeded];
        self.constraintScrollViewCenterY.constant += self.tabBarController.tabBar.frame.size.height;

        [coordinator addCoordinatedAnimations:^{
            [self.view layoutIfNeeded];
        } completion:nil];
    }

其中self.constraintScrollViewCenterY是与我要根据标签栏移动移动的视图的垂直对齐相关的约束

注意：使用class名称（kUITabBarButtonClassName）而不是[...class]方法是因为UITabBarButton是私有的class

TvOS UITabBarController 检测标签栏 shown/hidden

TvOS UITabBarController detect tabbar shown/hidden

objective-c

uitabbarcontroller

uitabbar

tvos

apple-tv