UITabBarController取消再次点击已选中tab时回到UINavigationController的rootViewController

设置tabBarController的delegate, 并实现delegate中的tabBarController:shouldSelectViewController方法

?

- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
{
??? AppUtilsLog(NSStringFromSelector(_cmd));
??? UIViewController* selectedViewController = tabBarController.selectedViewController;
??? if (selectedViewController == viewController) {
??????? return NO;
??? } else {
??????? return YES;
??? }??
}