iPad中將UITabBar的圖標和文字改爲上下結構顯示

@implementation UITabBarController (TabButtonType)
- (UITraitCollection *)traitCollection {
    UITraitCollection *oldTrait = super.traitCollection;
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
        UITraitCollection *tmpTrait = [UITraitCollection traitCollectionWithHorizontalSizeClass: UIUserInterfaceSizeClassCompact];
        UITraitCollection *newTrait = [UITraitCollection traitCollectionWithTraitsFromCollections:@[oldTrait, tmpTrait]];
        return newTrait;
    }
    return oldTrait;
}
@end