GCD高级编程例子

两种方法，实现一件事情做完，再做另外一件事情。 

1、

dispatch_async(dispatch_get_main_queue(), ^{

[self.navigationController popToRootViewControllerAnimated:NO];

});

dispatch_barrier_async(dispatch_get_main_queue(), ^{

[[[AppDelegate getDelegate] tabbarController] setSelectedIndex:0];

});

2、

dispatch_group_t group =dispatch_group_create();

dispatch_group_async(group, dispatch_get_main_queue(), ^{

[self.navigationControllerpopToRootViewControllerAnimated:NO];

});

dispatch_group_notify(group, dispatch_get_main_queue(), ^{

[[[AppDelegategetDelegate] tabbarController]setSelectedIndex:0];

});

出现问题的代码如下：

[self.navigationController popToRootViewControllerAnimated:NO];

GCD高级编程例子

原文：http://blog.csdn.net/winsdom123456/article/details/41014561