In iOS 7, we can now add a constraint between a view and the top layout guide, which I think is very useful to solve the status bar offset issue in iOS7(especially when ther
Until now even using XCode 6 I cannot align controls to top layout guide on .xib files. Instead, I am using an alternative way.
First, on interface builder, I still align controls to top border of viewcontroler's view.
Then, in viewDidLoad method, I replace some constraints so they will align to top layout guide instead of main view:
- (void)viewDidLoad
{
[super viewDidLoad];
NSArray *constraints = self.view.constraints;
for (NSLayoutConstraint *constraint in constraints) {
if ( (constraint.firstItem == self.view) && (constraint.firstAttribute == NSLayoutAttributeTop) ) {
NSLayoutConstraint *newConstraint = [self constraint:constraint replaceFirstItemBy:self.topLayoutGuide attribute:NSLayoutAttributeBottom];
[self.view removeConstraint:constraint];
[self.view addConstraint:newConstraint];
} else if ( (constraint.secondItem == self.view) && (constraint.secondAttribute == NSLayoutAttributeTop) ) {
NSLayoutConstraint *newConstraint = [self constraint:constraint replaceSecondItemBy:self.topLayoutGuide attribute:NSLayoutAttributeBottom];
[self.view removeConstraint:constraint];
[self.view addConstraint:newConstraint];
}
}
}
- (NSLayoutConstraint*)constraint:(NSLayoutConstraint*)constraint replaceFirstItemBy:(id)newItem attribute:(NSLayoutAttribute)newAttribute {
UILayoutPriority priority = constraint.priority;
NSLayoutRelation relation = constraint.relation;
id secondItem = constraint.secondItem;
NSLayoutAttribute secondAttribute = constraint.secondAttribute;
CGFloat multiplier = constraint.multiplier;
CGFloat constant = constraint.constant;
NSLayoutConstraint *newConstraint = [NSLayoutConstraint constraintWithItem:newItem attribute:newAttribute relatedBy:relation toItem:secondItem attribute:secondAttribute multiplier:multiplier constant:constant];
newConstraint.priority = priority;
return newConstraint;
}
- (NSLayoutConstraint*)constraint:(NSLayoutConstraint*)constraint replaceSecondItemBy:(id)newItem attribute:(NSLayoutAttribute)newAttribute {
UILayoutPriority priority = constraint.priority;
id firstItem = constraint.firstItem;
NSLayoutAttribute firstAttribute = constraint.firstAttribute;
NSLayoutRelation relation = constraint.relation;
CGFloat multiplier = constraint.multiplier;
CGFloat constant = constraint.constant;
NSLayoutConstraint *newConstraint = [NSLayoutConstraint constraintWithItem:firstItem attribute:firstAttribute relatedBy:relation toItem:newItem attribute:newAttribute multiplier:multiplier constant:constant];
newConstraint.priority = priority;
return newConstraint;
}
Think this is not the best way because we replace objects that we define on interface builder. But it may be an alternative way that we can think about.