Date pickers selection's overlay not adjusting when screen rotates - ios

Question

I've got a view with two date pickers set to cover the entire view's height and half a width each, so that they are filling the entire view.
I've then added an overlay to each picker to make the selection more visible, like this:
-(void)drawOverlays {
if (_overlay1 != nil) {
[_overlay1 removeFromSuperview];
}
if (_overlay2 != nil) {
[_overlay2 removeFromSuperview];
}
_overlay1 = [[UIView alloc] initWithFrame:CGRectMake(_startPicker.bounds.origin.x, (_startPicker.frame.size.height/2)-19, _startPicker.bounds.size.width, 38)];
_overlay1.backgroundColor = [UIColor redColor];
_overlay1.alpha = 0.5f;
[_startPicker addSubview:_overlay1];
_overlay2 = [[UIView alloc] initWithFrame:CGRectMake(_endPicker.bounds.origin.x, (_endPicker.frame.size.height/2)-19, _endPicker.bounds.size.width, 38)];
_overlay2.backgroundColor = [UIColor redColor];
_overlay2.alpha = 0.5f;
[_endPicker addSubview:_overlay2];
}
I'm calling this method from the -viewDidLayoutSubviews method and from the -viewWillTransitionToSize:withTransitionCoordinator method, and the first time the view appears everything is fine.
Then I rotate my iPad and the overlays are shown inverted, meaning that when in landscape the overlays are the size I want for the portrait and vice versa.
What's wrong with my code?

Answer 1

You will be much better off using constraints and letting auto-layout handle the resizing:
-(void)drawOverlays {
if (_overlay1 != nil) {
[_overlay1 removeFromSuperview];
}
if (_overlay2 != nil) {
[_overlay2 removeFromSuperview];
}
//_overlay1 = [[UIView alloc] initWithFrame:CGRectMake(_startPicker.bounds.origin.x, (_startPicker.frame.size.height/2)-19, _startPicker.bounds.size.width, 38)];
// instantiate overlay1
_overlay1 = [UIView new];
_overlay1.backgroundColor = [UIColor redColor];
_overlay1.alpha = 0.5f;
// add as subview of startPicker
[_startPicker addSubview:_overlay1];
//_overlay2 = [[UIView alloc] initWithFrame:CGRectMake(_endPicker.bounds.origin.x, (_endPicker.frame.size.height/2)-19, _endPicker.bounds.size.width, 38)];
// instantiate overlay2
_overlay2 = [UIView new];
_overlay2.backgroundColor = [UIColor redColor];
_overlay2.alpha = 0.5f;
// add as subview of endPicker
[_endPicker addSubview:_overlay2];
// we want to use auto-layout / constraints
_overlay1.translatesAutoresizingMaskIntoConstraints = NO;
_overlay2.translatesAutoresizingMaskIntoConstraints = NO;
[NSLayoutConstraint activateConstraints:#[
// constrain overlay1 to startPicker
// centerY
// leading / trailing = 0
// height = 38
[_overlay1.centerYAnchor constraintEqualToAnchor:_startPicker.centerYAnchor],
[_overlay1.leadingAnchor constraintEqualToAnchor:_startPicker.leadingAnchor constant:0.0],
[_overlay1.trailingAnchor constraintEqualToAnchor:_startPicker.trailingAnchor constant:0.0],
[_overlay1.heightAnchor constraintEqualToConstant:38.0],
// constrain overlay2 to startPicker
// centerY
// leading / trailing = 0
// height = 38
[_overlay2.centerYAnchor constraintEqualToAnchor:_endPicker.centerYAnchor],
[_overlay2.leadingAnchor constraintEqualToAnchor:_endPicker.leadingAnchor constant:0.0],
[_overlay2.trailingAnchor constraintEqualToAnchor:_endPicker.trailingAnchor constant:0.0],
[_overlay2.heightAnchor constraintEqualToConstant:38.0],
]
];
}
And, this only needs to be called from viewDidLoad (or wherever else you may find it appropriate). There is no need for it to be -- and in fact, it should not be -- called from viewDidLayoutSubviews or viewWillTransitionToSize.
As a side note -- if you are using remove and re-add to show and hide them, you'll also get a little better optimization if you add them once, and then set the .hidden property to YES or NO.