点击登录按钮，跳转到登录的ViewController，为什么我的不跳转呢，帮忙看下

- (IBAction)btnLoginClick {
LoginViewController *loginView = [[LoginViewController alloc] initWithNibName:@"LoginViewController" bundle:nil];
//UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:loginView];
//[self.navigationController presentModalViewController:nav animated:YES];
//[self.navigationController pushViewController:loginView animated:YES];
[self.navigationController presentModalViewController:loginView animated:YES];
//[nav release];
[loginView release];
NSLog(@"aaa");
}

注释掉的我也试过 都不行，还是没动静，控制台输出了 aaa
[解决办法]
[self presentModalViewController:loginView animated:YES];

navigationController 应该没初始化
[解决办法]
1. NSAssert(self.navigationController != nil, @"nothing");

2. Breakpoint debug