Is there an iOS method that fires when Autolayout has completed?

The following can be used to avoid multiple calls:

- (void) didFinishAutoLayout {

    // Do some stuff here.    

    NSLog(@"didFinishAutoLayout");
}

and

- (void) viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];


    [NSObject cancelPreviousPerformRequestsWithTarget:self
                                 selector:@selector(didFinishAutoLayout)
                                           object:nil];
    [self performSelector:@selector(didFinishAutoLayout) withObject:nil
               afterDelay:0];
}

I'm using viewDidLayoutSubviews for this. Apple's documentation says, "Called to notify the view controller that its view has just laid out its subviews."

If you watched 2018's WWDC about "High-Performance AutoLayout", you would know the answer to this question.

Technically, there is no such API method that will be called when autolayout has completed your view's layout. But when autolayout has completed the calculations, your view's setBounds and setCenter will be called so that your view gets its size and position.

After this, your view's layoutSubviews will be called. So, layoutSubviews can, to some degree, be thought of as the method that fires after autolayout has done calculations.

As to view controller's viewDidLayoutSubviews, this is a bit complicated. The documentation says:

When the bounds change for a view controller's view, the view adjusts the positions of its subviews and then the system calls this method. However, this method being called does not indicate that the individual layouts of the view's subviews have been adjusted. Each subview is responsible for adjusting its own layout.

So when viewDidLayoutSubviews called on a view controller, only the view controller'view 's first-level subviews are guaranteed to be laid out correctly.