Getting subViews' frames in Storyboard

Question

I just want (for now) to get the dimensions of a subview on the view controller\'s instantiation.

[This is a reduction to as simple a case I can find of a previous

Answer 1

There is a Related issue that I am compelled to address, which hopefully will save someone else a day of debugging:

I am finding out that in Storyboard:

1. segue-push does not cause subViews to be laid out at -viewDidLayoutSubviews (they are instead laid out at some other time just before -viewDidAppear).
   Whereas...
2. segue-modal and [navController.storyboard presentViewController:] does cause subViews to be laid out at -viewDidLayoutSubviews.

The solution is to put [self.mySubView layoutSubviews] within the viewController's -viewDidLayoutSubviews method in order to manually load the subViews within mySubView.

My case was that I had a custom gradient button that was not properly initializing it's visual appearance.
The button was contained within a scrollView that contained a CustomView which contained the custom gradient button.
So, basically... a button within a view within a scrollView.

The app starts out with a UINavigationController having some other ViewController1 loaded.
ViewController1 contains a button which, when pressed, launches a storyboard segue-push to ViewController2.
(this was arranged in storyboard by control-dragging from the button in ViewController1 to ViewController2).

ViewController2 contains the scrollview/customView/customButton.
In ViewController2's -viewDidLayoutSubviews, I initialize the customButton which is a custom Gradient Button having it's own .h/.m files.
GradientButton.m has an initLayers method which configures it graphically and requires the bounds/frame property of the button to be initialized.
However...
in ViewController2's -viewDidLayoutSubviews, self.customButton had a frame of 0,0,0,0.

A few notes:

1. Yes, I am calling [super viewDidLayoutSubviews] at the beginning of -viewDidLayoutSubviews.
2. The only view that has been laid out at -viewDidLayoutSubviews is self.view (ViewController2's initial view, as connected in Storyboard's connections panel. in my case - self.view is a scrollView).

To resolve:

1. in ViewController2, I created an outlet self.bottomView for the view that contained self.customButton.
2. in ViewController2's -viewDidLayoutSubviews, I call [self.bottomView layoutSubviews]
   • This will then cause customButton's frame/bounds to be properly set.
3. Next, I call [self.customButton initLayers] which now properly initializes my custom gradient button.

A few notes about ViewController2's -viewDidLayoutSubviews: calling [self.view layoutSubviews] causes bottomView's frame to be initialized, but NOT customButton's frame.
In terms of a view hierarchy, -layoutSubviews applies only to the subViews of self.view and not to any subViews of those subViews.
This only appears to be the case with storyboard segue-push.

The storyboard segue-modal and the programmatic [navController presentViewController] both seem to correctly initialize all levels of the view hierarchy (all "subViews of subViews") by the time -viewDidLayoutSubviews is called.

Answer 2

Those dimensions are calculated and set when the call to layoutSubviews is made, which occurs after viewWillAppear. After layoutSubviews is called on the UIVIew you can get the dimensions.

Look at implementing this method in your view controller: viewDidLayoutSubviews. At this point you should be able to get dimensions of your subviews. Note that this call is available starting in iOS 5.0 but since you reference storyboards I assume you are working at or above that anyway.

- (void)viewDidLayoutSubviews
{
    [super viewDidLayoutSubviews];

    NSLog(@"View Controller did layout subviews. firstViewFirstSubView: %@ ", firstViewFirstSubView);
    NSLog(@"subView's dimmensions: %f by %f at %f, %f", firstViewFirstSubView.frame.size.width,
      firstViewFirstSubView.frame.size.height,
      firstViewFirstSubView.frame.origin.x,
      firstViewFirstSubView.frame.origin.y);
}