Question

I came across this while debugging why my scrollView wouldn’t scroll. For context, the structure of my layout is:

-ScrollView
  - View
     - labels, images, buttons

Updating the scrollView.contentSize to match the (sub)view wasn’t working, so I put in some debug statements. Turns out the view’s frame is sized 0, 0 when i NSLog its description, but if i run the debugger’s recursiveDescription, it shows different.

Any idea why, and could that be affecting why my scrolling isn’t working?

From NSLog(@"%@", [self.view description])

2012-11-15 17:16:46.707 Comparo[65731:11303] starting: <UIView:
0x7144590; frame = (0 0; 0 0); autoresize = TM+BM; layer =
<CALayer: 0x714b4f0>>

2012-11-15 17:16:46.708 Comparo[65731:11303] 1: <UIView: 0x7144590;
frame = (0 0; 0 0); autoresize = TM+BM; layer = <CALayer:
0x714b4f0>>

2012-11-15 17:16:46.771 Comparo[65731:11303] 2: <UIView: 0x7144590;
frame = (0 0; 0 0); autoresize = TM+BM; layer = <CALayer:
0x714b4f0>>

2012-11-15 17:16:46.771 Comparo[65731:11303] 3: <UIView: 0x7144590;
frame = (0 0; 0 0); autoresize = TM+BM; layer = <CALayer:
0x714b4f0>>

2012-11-15 17:16:46.772 Comparo[65731:11303] 4: <UIView: 0x7144590;
frame = (0 0; 0 0); autoresize = TM+BM; layer = <CALayer:
0x714b4f0>>

Debugger output for: (lldb) po [[UIApp keyWindow] recursiveDescription]

…

| | | | <UIScrollView: 0x71494d0; frame = (0 0; 320 504);
clipsToBounds = YES; autoresize = TM+BM; gestureRecognizers =
<NSArray: 0x75d3bb0>; layer = <CALayer: 0x71f9ed0>;
contentOffset: {0, 0}>

| | | | | <UIView: 0x7144590; frame = (0 0; 320 523);
autoresize = TM+BM; layer = <CALayer: 0x714b4f0>>

Thanks.

Answer 1

Thanks Rob!

You were right about it being a timing issue and there’s no way to guarantee that frames will be finalized in viewDidLoad (where I had my NSLog statements). I moved the statements to viewDidAppear:, which is where the user will first be able to interact with them and scroll anyway, and the numbers match up now.

Bonus: solved my scrolling issue too.