How to pop a viewController and then Push a viewController through delegation

Question

I have a UITableViewController that when a cell is pressed, I want the controller to pop itself, and then have the controller it pop's to, push another view controller onto the stack.

I am invoking this method because the popped-to viewController is the delegate of the tableViewController

I am currently invoking this method with a delay on it, because otherwise, everything gets screwed up waiting for the animation to end. Doing it this way seems a bit hacky and seems to me like it would fail if someone's device didn't pop the view in the allotted wait time I have given it.

Here is some of the code:

//**** code in my tableViewController ***//

[self.navigationController popViewControllerAnimated:YES];
[self.delegate cellPressedInTableViewControllerWithCalculationsModel:(id)anArgmentMyDelegateMethodTakes];



// **** Code in the viewController being popped to ****//
//CalculationsViewController is a subclass of UIViewController
CalculationsViewController *calcViewController = [[CalculationsViewController alloc] init];

//some customization code would go her

[self.navigationController performSelector:@selector(pushViewController:animated:) withObject:calcViewController afterDelay:0.75];
//this seems like the arbitrary part, the 0.75 second delay.

[calcViewController release];

There seems like there should be a better way to pop/push through delegation that will execute after the animation finishes. The wait time seems to me like it could cause unexpected problems.

I have also tried using:

 performSelectorOnMainThread:withObject:waitUntilDone

But the code just executes immediately and the view hierarchy screwed up.

I have also looked at this question: Delegation question and it has gotten me this far, but I am curious to see if there is a better way to perform such a task, Thanks.

edit: I have also tried wrapping the method in an instance of NSInvocation, and I couldn't get it to coordinate the method call until after the animation finished without arbitrarily setting the delay

Answer 1

The cleanest way to do more than a single push or pop of a view controller is to set the UINavigationControllers view controllers array.

For example, to pop and then push a view controller:

MyTableViewController *vc = [[MyTableViewController alloc] init];

NSMutableArray *controllers = [NSMutableArray arrayWithArray:self.navigationController.viewControllers];
[controllers removeLastObject];
[controllers addObject:vc];

[self.navigationController setViewControllers:controllers animated:YES];

Answer 2

You should use a flag to overcome this situation. You set this flag in viewWillDisappear method of view controller being popped. When this flag is set then and then you can push another view controller on stack. Hope it's clear.

Answer 3

How about when you dismiss your UIViewController containing the table you send a NSNotifcation in your viewDidDisappear method like so:

- (void)viewDidDisappear:(BOOL)animated
{
    [[NSNotificationCenter defaultCenter] postNotificationName:@"loadOtherVC" object:nil];
}

And in your parent view controller that will push a new view controller, you add an observer for that notification like so:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(LoadOtherVC:) name:@"loadOtherVC" object:nil];

You should have a method that matches the selector.

- (void) LoadOtherVC:(NSNotification *) notification
{
    // load your other view controller you want here
}

Answer 4

I liked Alexandre's solution but if I were a delegate person, I wouldn't want to use notification. So in that case, we can just use the delegate in the viewDidDisappear method.

So, in the didSelectRowAtIndexPath method, you can pop the controller-

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
     [self.navigationController popViewControllerAnimated:YES];
}

and in the same View Controller, the ViewController you are popping, call the delegate method in the viewDidDisappear method like-

-(void)viewDidDisappear:(BOOL)animated{
   [self.delegate cellPressedInTableViewControllerWithCalculationsModel:(id)anArgmentMyDelegateMethodTakes];
}

Then in the controller that is pushed can implement the delegate method and inside that delegate method, you can do whatever you want.

Answer 5

Don't pop it from the top level controller. Call the delegate method that will pop the view off the navigation controller and then push a new one on.