iOS 怎么设置 UITabBarController 的第n个item为第一响应者?
UITabBarController 里面有个属性：selectedIndex
@property(nonatomic) NSUInteger selectedIndex;
UITabBarController *VC = [[UITabBarController alloc]init];
VC.selectedIndex = n-1;
[self.navigationController pushViewController:VC animated:YES];