How does view layering affect a views positioning? - ios

Question

This question has been re-written, since I think it has more to do with views and layers than the original 'Finding the center of a tableview'. Also in hope of finding another answer.
In question, is a set of 4 views to show activity, in a tableview, in a tab bar.
The code of:
NSLog(#"view.center: %#", self.view.center);
NSLog(#"view.frame: %#", self.view.frame);
Produces, on first display of 'loading':
view.center: {160, 250}
view.frame: {{0, 20}, {320, 460}}
For 2nd (and subsequent) displays: (after a pop up date picker)
view.center: {160, 205.5}
view.frame: {{0, 0}, {320, 411}}
Self (ListViewController) is subclass of UITableViewController. So, the height of the view (or tableview) frame is changing. Why?
I've been exploring and found this info in the debugger, that seems relevant.
--- Before ---
[self parentViewController]:
<UITabBarController: 0x6e115a0>
[[self parentViewController] view]:
<UILayoutContainerView: 0x6e1b750; frame = (0 0; 320 480); autoresize = W+H; layer = <CALayer: 0x6e0c8f0>>
self: <ListsViewController: 0x6e13730>
[self tableView]:
<UITableView: 0x71e4000; frame = (0 20; 320 460); clipsToBounds = YES; opaque = NO; autoresize = W+H; layer = <CALayer: 0x6834db0>; contentOffset: {0, 0}>
[[self view] subviews]: (array)
<UIImageView: 0x6825e30; frame = (0 453; 320 7); alpha = 0; opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x6835a90>>,
<UIImageView: 0x68314e0; frame = (313 411; 7 20); alpha = 0; opaque = NO; autoresize = LM; userInteractionEnabled = NO; layer = <CALayer: 0x683d120>>,
<UIView: 0x6a054f0; frame = (0 0; 320 460); alpha = 0.4; tag = 12; layer = <CALayer: 0x6a07840>>,
<UIView: 0x6a04c60; frame = (110 155.5; 100 100); alpha = 0.6; tag = 13; layer = <CALayer: 0x6a073c0>>,
<UILabel: 0x6a07480; frame = (110 200.5; 100 50); text = 'Loading ...'; clipsToBounds = YES; userInteractionEnabled = NO; tag = 14; layer = <CALayer: 0x6a065b0>>,
<UIActivityIndicatorView: 0x6a07a80; frame = (140 167.5; 40 40); tag = 15; layer = <CALayer: 0x6a07b40>>
--- After datepicker ---
[self parentViewController]:
<UITabBarController: 0x6e115a0>
[self parentViewController] view]:
<UILayoutContainerView: 0x6e1b750; frame = (0 0; 320 480); autoresize = W+H; layer = <CALayer: 0x6e0c8f0>>
self: <ListsViewController: 0x6e13730>
[self tableView]:
<UITableView: 0x71e4000; frame = (0 0; 320 411); clipsToBounds = YES; opaque = NO; autoresize = W+H; layer = <CALayer: 0x6834db0>; contentOffset: {0, 0}>
[[self view] subviews]:
<DetailTableViewCell: 0xb642120; baseClass = UITableViewCell; frame = (0 369; 320 44); autoresize = W; layer = <CALayer: 0xb642230>>,
<DetailTableViewCell: 0xb643850; baseClass = UITableViewCell; frame = (0 325; 320 44); autoresize = W; layer = <CALayer: 0xb643960>>,
<DetailTableViewCell: 0xb6435c0; baseClass = UITableViewCell; frame = (0 281; 320 44); autoresize = W; layer = <CALayer: 0xb6436d0>>,
<DetailTableViewCell: 0xb63cf30; baseClass = UITableViewCell; frame = (0 237; 320 44); autoresize = W; layer = <CALayer: 0xb63d130>>,
<DetailTableViewCell: 0x6a14050; baseClass = UITableViewCell; frame = (0 193; 320 44); autoresize = W; layer = <CALayer: 0x6a16fb0>>,
<DetailTableViewCell: 0x6a13760; baseClass = UITableViewCell; frame = (0 149; 320 44); autoresize = W; layer = <CALayer: 0x6a13870>>,
<DetailTableViewCell: 0x6a10920; baseClass = UITableViewCell; frame = (0 105; 320 44); autoresize = W; layer = <CALayer: 0x6a10010>>,
<DetailTableViewCell: 0xb63ce20; baseClass = UITableViewCell; frame = (0 60; 320 45); autoresize = W; layer = <CALayer: 0xb63c3e0>>,
<UIImageView: 0x6825e30; frame = (0 404; 320 7); alpha = 0; opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x6835a90>>,
<UIView: 0xb6477f0; frame = (0 0; 320 60); autoresize = W; layer = <CALayer: 0xb647820>>,
<UIImageView: 0x68314e0; frame = (313 411; 7 20); alpha = 0; opaque = NO; autoresize = LM; userInteractionEnabled = NO; layer = <CALayer: 0x683d120>>,
<UIView: 0x6a098a0; frame = (0 0; 320 411); alpha = 0; tag = 9; animations = { opacity <CABasicAnimation: 0xb6279f0>; }; layer = <CALayer: 0x6a154b0>>,
<UIDatePicker: 0x6a23350; frame = (0 455; 320 216); tag = 10; animations = { position <CABasicAnimation: 0xb63bd40>; }; layer = <CALayer: 0x6a20590>>,
<UIToolbar: 0x6843f60; frame = (0 411; 320 44); opaque = NO; tag = 11; animations = { position=<CABasicAnimation: 0xb645f80>; }; layer = <CALayer: 0x6844a20>>,
<UIView: 0xb60baa0; frame = (0 0; 320 411); alpha = 0.4; tag = 12; layer = <CALayer: 0xb626af0>>,
<UIView: 0xb626b20; frame = (110 155.5; 100 100); alpha = 0.6; tag = 13; layer = <CALayer: 0xb626930>>,
<UILabel: 0xb60cfb0; frame = (110 200.5; 100 50); text = 'Loading ...'; clipsToBounds = YES; userInteractionEnabled = NO; tag = 14; layer = <CALayer: 0xb60d020>>,
<UIActivityIndicatorView: 0xb649e20; frame = (140 167.5; 40 40); tag = 15; layer = <CALayer: 0xb626960>>

Answer 1

You can use tableview.frame to access the origin points and it's dimensions. You can use tablview.center which is a CGPoint which gives you the center point of the object.