how to set subview of UIScrollView using autolayout - ios

Question

i am trying to implement Horizontal scrollview with ten views.
its working fine in portrait mode but i want same scenario in landscape too.
can anyone help me by which constraint i can achieve this?
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.title=#"Demo.....";
self.myScrollView.pagingEnabled = YES;
NSInteger numberOfViews = 10;
for (int i = 0; i < numberOfViews; i++) {
CGFloat myOrigin = i * self.view.frame.size.width;
UIView *myView = [[UIView alloc] initWithFrame:CGRectMake(myOrigin, 0, self.view.frame.size.width, self.view.frame.size.height)];
myView.backgroundColor = [UIColor purpleColor];
CGRect myFrame = CGRectMake(10.0f, 70.0f, 200.0f, 25.0f);
UILabel *myLabel = [[UILabel alloc] initWithFrame:myFrame];
myLabel.translatesAutoresizingMaskIntoConstraints = NO;
myLabel.text = [NSString stringWithFormat:#"This is page number %d", i];
myLabel.font = [UIFont boldSystemFontOfSize:16.0f];
myLabel.textAlignment = NSTextAlignmentLeft;
[myView addSubview:myLabel];
//set the scroll view delegate to self so that we can listen for changes
self.myScrollView.delegate = self;
//add the subview to the scroll view
[self.myScrollView addSubview:myView];
NSLayoutConstraint *constraintLeft = [NSLayoutConstraint constraintWithItem:myView
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.myScrollView
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:0.0];
// 0px to the right of the UIScrollView
NSLayoutConstraint *constraintRight = [NSLayoutConstraint constraintWithItem:myView
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.myScrollView
attribute:NSLayoutAttributeRight
multiplier:1.0
constant:0.0];
[self.myScrollView addConstraint:constraintLeft];
[self.myScrollView addConstraint:constraintRight];
}
//set the content size of the scroll view, we keep the height same so it will only
//scroll horizontally
self.myScrollView.contentSize = CGSizeMake(self.view.frame.size.width * numberOfViews,
self.view.frame.size.height);
//we set the origin to the 3rd page
CGPoint scrollPoint = CGPointMake(self.view.frame.size.width * 2, 0);
//change the scroll view offset the the 3rd page so it will start from there
[myScrollView setContentOffset:scrollPoint animated:YES];
[self.view addSubview:self.myScrollView];
}
in my above code,
ten view is completely added into scrollview and working fine in portrait mode but when i change the orientation to horizontal it will not resize and not scrolled.

Answer 1

You need to tie subviews width constraint equal to scrollView width
for (UIView *subView in subViews)
{
NSLayoutConstraint *constraintEqualWidth = [NSLayoutConstraint constraintWithItem:subView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.myScrollView
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0.0];
[subView addConstraint:constraintEqualWidth];
}