第一种方案:
AppDelegate * appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
UIViewController * controller = appDelegate.window.rootViewController;
UITabBarController * tabBarController = (UITabBarController *)controller;
[tabBarController setSelectedIndex:3];
//假如要跳转到第四个tabBar那里,因为tabBar默认索引是从0开始的
[self.navigationController popToRootViewControllerAnimated:YES];
第二种方案:
self.navigationController.tabBarController.selectedIndex = 3;
第三种方案:
self.tabBarController.selectedIndex = 3;