问题
I wanted to sent one container below the other on portrait and side by side on landscape. Is it possible with just auto layout? I know i can do it programmatically, just wondering if it is possible to do it from the layout.
Like This:
回答1:
Well didRotateFromInterfaceOrientation is not the preferred way to do these kind of things with iOS 8. I would suggest you to take a look at traitCollection and view controller methods associated with it. The trick here is to install horizontal constraint or vertical constraint when UIViewController method viewWillTransitionToSize:withTransitionCoordinator: trigger.
Here is the way I did it,
@interface ViewController ()
@property (nonatomic, weak) UIView *aContainerView;
@property (nonatomic, weak) UIView *bContainerView;
@property (nonatomic, strong) NSArray *horizontalOrientationConstraints;
@property (nonatomic, strong) NSArray *verticalOrientationConstraints;
@end
@implementation ViewController
#pragma mark - Getters
- (NSArray *)horizontalOrientationConstraints
{
if (!_horizontalOrientationConstraints) {
NSLayoutConstraint *equalWidthConstraints = [NSLayoutConstraint constraintWithItem:self.aContainerView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.bContainerView
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0];
NSArray *vConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|[aContainerView][bContainerView]|"
options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom
metrics:nil views:@{@"aContainerView": self.aContainerView, @"bContainerView": self.bContainerView}];
NSArray *hConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[aContainerView]|"
options:0
metrics:nil
views:@{@"aContainerView": self.aContainerView}];
NSArray *constraints = [vConstraints arrayByAddingObjectsFromArray:hConstraints];
_horizontalOrientationConstraints = [constraints arrayByAddingObject:equalWidthConstraints];
}
return _horizontalOrientationConstraints;
}
- (NSArray *)verticalOrientationConstraints
{
if (!_verticalOrientationConstraints) {
NSLayoutConstraint *equalHeightConstraints = [NSLayoutConstraint constraintWithItem:self.aContainerView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:self.bContainerView
attribute:NSLayoutAttributeHeight
multiplier:1.0
constant:0];
NSArray *vConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[aContainerView][bContainerView]|"
options:NSLayoutFormatAlignAllLeft | NSLayoutFormatAlignAllRight
metrics:nil views:@{@"aContainerView": self.aContainerView, @"bContainerView": self.bContainerView}];
NSArray *hConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|[aContainerView]|"
options:0
metrics:nil
views:@{@"aContainerView": self.aContainerView}];
NSArray *constraints = [vConstraints arrayByAddingObjectsFromArray:hConstraints];
_verticalOrientationConstraints = [constraints arrayByAddingObject:equalHeightConstraints];
}
return _verticalOrientationConstraints;
}
#pragma mark -
- (void)viewDidLoad
{
[super viewDidLoad];
UIView *aContainerView = [self viewWithLabelText:@"A" andBackgroundColor:[UIColor yellowColor]];
UIView *bContainerView = [self viewWithLabelText:@"B" andBackgroundColor:[UIColor greenColor]];
[self.view addSubview:aContainerView];
[self.view addSubview:bContainerView];
self.aContainerView = aContainerView;
self.bContainerView = bContainerView;
CGSize viewSize = self.view.bounds.size;
if (viewSize.width > viewSize.height) {
[NSLayoutConstraint activateConstraints:self.horizontalOrientationConstraints];
} else {
[NSLayoutConstraint activateConstraints:self.verticalOrientationConstraints];
}
}
- (UIView *)viewWithLabelText:(NSString *)text andBackgroundColor:(UIColor *)color
{
UIView *aContainerView = [[UIView alloc] init];
aContainerView.backgroundColor = [UIColor blackColor];
aContainerView.translatesAutoresizingMaskIntoConstraints = NO;
UIView *aView = [[UIView alloc] init];
aView.translatesAutoresizingMaskIntoConstraints = NO;
aView.backgroundColor = color;
UILabel *aLabel = [[UILabel alloc] init];
aLabel.translatesAutoresizingMaskIntoConstraints = NO;
aLabel.text = text;
aLabel.font = [UIFont systemFontOfSize:80];
[aView addSubview:aLabel];
[aContainerView addSubview:aView];
NSLayoutConstraint *centerXConstraints = [NSLayoutConstraint constraintWithItem:aView
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:aLabel
attribute:NSLayoutAttributeCenterX
multiplier:1.0
constant:0];
NSLayoutConstraint *centerYConstraints = [NSLayoutConstraint constraintWithItem:aView
attribute:NSLayoutAttributeCenterY
relatedBy:NSLayoutRelationEqual
toItem:aLabel
attribute:NSLayoutAttributeCenterY
multiplier:1.0
constant:0];
[aContainerView addConstraints:@[centerXConstraints, centerYConstraints]];
NSString *hConstraintsFormat = @"V:|-10-[view]-10-|";
NSString *vConstraintsFormat = @"H:|-10-[view]-10-|";
[aContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:hConstraintsFormat
options:0
metrics:nil
views:@{@"view": aView}]];
[aContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:vConstraintsFormat
options:0
metrics:nil
views:@{@"view": aView}]];
return aContainerView;
}
- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
NSArray *constraintsToDeactivate;
NSArray *constraintsToActivate;
if (size.width > size.height) {
constraintsToActivate = self.horizontalOrientationConstraints;
constraintsToDeactivate = self.verticalOrientationConstraints;
} else {
constraintsToActivate = self.verticalOrientationConstraints;
constraintsToDeactivate = self.horizontalOrientationConstraints;
}
[NSLayoutConstraint deactivateConstraints:constraintsToDeactivate];
[NSLayoutConstraint activateConstraints:constraintsToActivate];
[self.view layoutIfNeeded];
}
@end
Here is how it looks for both the orientations,
For iOS7, you basically do the same thing. Instead of overriding viewWillTransitionToSize: you should rather override willAnimateRotationToInterfaceOrientation:duration:. Then you add or remove the constraint inside the method,
@interface ViewController ()
@property (nonatomic, weak) UIView *aContainerView;
@property (nonatomic, weak) UIView *bContainerView;
@property (nonatomic, assign) BOOL touchExited;
@property (nonatomic, assign) NSUInteger count;
@property (nonatomic, weak) NSTimer *countChangeTimer;
@property (nonatomic, weak) UIButton *theCountButton;
@property (nonatomic, strong) NSArray *horizontalOrientationConstraints;
@property (nonatomic, strong) NSArray *verticalOrientationConstraints;
@end
@implementation ViewController
#pragma mark - Getters
- (NSArray *)horizontalOrientationConstraints
{
if (!_horizontalOrientationConstraints) {
NSLayoutConstraint *equalWidthConstraints = [NSLayoutConstraint constraintWithItem:self.aContainerView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.bContainerView
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0];
NSArray *vConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|[aContainerView][bContainerView]|"
options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom
metrics:nil views:@{@"aContainerView": self.aContainerView, @"bContainerView": self.bContainerView}];
NSArray *hConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[aContainerView]|"
options:0
metrics:nil
views:@{@"aContainerView": self.aContainerView}];
NSArray *constraints = [vConstraints arrayByAddingObjectsFromArray:hConstraints];
_horizontalOrientationConstraints = [constraints arrayByAddingObject:equalWidthConstraints];
}
return _horizontalOrientationConstraints;
}
- (NSArray *)verticalOrientationConstraints
{
if (!_verticalOrientationConstraints) {
NSLayoutConstraint *equalHeightConstraints = [NSLayoutConstraint constraintWithItem:self.aContainerView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:self.bContainerView
attribute:NSLayoutAttributeHeight
multiplier:1.0
constant:0];
NSArray *vConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[aContainerView][bContainerView]|"
options:NSLayoutFormatAlignAllLeft | NSLayoutFormatAlignAllRight
metrics:nil views:@{@"aContainerView": self.aContainerView, @"bContainerView": self.bContainerView}];
NSArray *hConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|[aContainerView]|"
options:0
metrics:nil
views:@{@"aContainerView": self.aContainerView}];
NSArray *constraints = [vConstraints arrayByAddingObjectsFromArray:hConstraints];
_verticalOrientationConstraints = [constraints arrayByAddingObject:equalHeightConstraints];
}
return _verticalOrientationConstraints;
}
#pragma mark -
- (void)invalidateTimer
{
if (self.countChangeTimer) {
[self.countChangeTimer invalidate];
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
UIView *aContainerView = [self viewWithLabelText:@"A" andBackgroundColor:[UIColor yellowColor]];
UIView *bContainerView = [self viewWithLabelText:@"B" andBackgroundColor:[UIColor greenColor]];
[self.view addSubview:aContainerView];
[self.view addSubview:bContainerView];
self.aContainerView = aContainerView;
self.bContainerView = bContainerView;
CGSize viewSize = self.view.bounds.size;
if (viewSize.width > viewSize.height) {
[self.view addConstraints:self.horizontalOrientationConstraints];
} else {
[self.view addConstraints:self.verticalOrientationConstraints];
}
}
- (UIView *)viewWithLabelText:(NSString *)text andBackgroundColor:(UIColor *)color
{
UIView *aContainerView = [[UIView alloc] init];
aContainerView.backgroundColor = [UIColor blackColor];
aContainerView.translatesAutoresizingMaskIntoConstraints = NO;
UIView *aView = [[UIView alloc] init];
aView.translatesAutoresizingMaskIntoConstraints = NO;
aView.backgroundColor = color;
UILabel *aLabel = [[UILabel alloc] init];
aLabel.translatesAutoresizingMaskIntoConstraints = NO;
aLabel.text = text;
aLabel.font = [UIFont systemFontOfSize:80];
[aView addSubview:aLabel];
[aContainerView addSubview:aView];
NSLayoutConstraint *centerXConstraints = [NSLayoutConstraint constraintWithItem:aView
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:aLabel
attribute:NSLayoutAttributeCenterX
multiplier:1.0
constant:0];
NSLayoutConstraint *centerYConstraints = [NSLayoutConstraint constraintWithItem:aView
attribute:NSLayoutAttributeCenterY
relatedBy:NSLayoutRelationEqual
toItem:aLabel
attribute:NSLayoutAttributeCenterY
multiplier:1.0
constant:0];
[aContainerView addConstraints:@[centerXConstraints, centerYConstraints]];
NSString *hConstraintsFormat = @"V:|-10-[view]-10-|";
NSString *vConstraintsFormat = @"H:|-10-[view]-10-|";
[aContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:hConstraintsFormat
options:0
metrics:nil
views:@{@"view": aView}]];
[aContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:vConstraintsFormat
options:0
metrics:nil
views:@{@"view": aView}]];
return aContainerView;
}
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
duration:(NSTimeInterval)duration{
NSArray *constraintsToDeactivate;
NSArray *constraintsToActivate;
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft || toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
constraintsToActivate = self.horizontalOrientationConstraints;
constraintsToDeactivate = self.verticalOrientationConstraints;
} else {
constraintsToActivate = self.verticalOrientationConstraints;
constraintsToDeactivate = self.horizontalOrientationConstraints;
}
[self.view removeConstraints:constraintsToDeactivate];
[self.view addConstraints:constraintsToActivate];
}
@end
回答2:
Yep, I think there is going to be a little code though. So the I believe the 2 constraints involved here are horizontal spacing and vertical spacing (Editor -> Pin -> Horizontal/Vertical).
Arrange A and B in the portrait layout, select both of the elements, and add both of those constraints. Create IBOutlets to both of these constraints in the header file (just like you would a label, button, etc)
You can then change the values of these constraints in the "didRotateFromInterfaceOrientation" delegate method (constraint_variable_name.constant = 0;). Let me know if any of this is unclear or you need me to elaborate on any part of it.
来源：https://stackoverflow.com/questions/27067078/ios-autolayout-change-position-on-rotation