modal

//就相当于show方式的pop

 [self dismissViewControllerAnimated:YES completion:^{ }];

- (IBAction)openClick
{
    UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    
   myModalViewController *nav = [sb instantiateViewControllerWithIdentifier:@"nav1"];
    
    [self presentViewController:nav animated:YES completion:^{
        
    }];
}