问题
Auto Layout, as good as it is, driving me crazy with constraints. I have the portrait mode designed in IB but I can't get the desired landscape orientation to work.
Notice that when the orientation changes to landscape, the spacing between the UIImageView blocks decreases and the text alignment of SAMPLE TEXT changes to right aligned.
Currently, I have added a few constraints for it to work. However, I need to keep the space between UIImageView blocks fixed, as a result of which it looks cramped up in portrait and fine in landscape. I need it to be spread out evenly in portrait and compress in landscape (like in image above). Similarly, currently my constraints bring up the text but it doesnot keep it at the center of screen and right aligned.
Is this possible at all with Auto Layout? If so, how? Help greatly appreciated.
回答1:
There are several ways to approach this. One way is to enclose your 3 image views in a UIView. Give the top and bottom image views constraints to the top and bottom respectively, and give the middle one a centerY constraint. Give this enclosing view a fixed height and width, and a constraint to the top of the controller's view. Make an IBOutlet to the height constraint for this enclosing view, and change it on rotation. In the example below, I gave it a height of 350 in portrait:
-(void)updateViewConstraints {
[super updateViewConstraints];
if (self.view.bounds.size.height < self.view.bounds.size.width) {
self.heightCon.constant = self.view.bounds.size.height;
}else{
self.heightCon.constant = 350;
}
}
As for the label, the easiest way is to remove the constraints you have (bottom and centerX), and add trailing and centerY on rotation.
回答2:
Yes, it can be done with Auto Layout. If you want the spacing between views to increase and/or decrease depending on orientation, you can use the Less Than or Equal or Greater Than or Equal relation (instead of Equal) for the constraint, which allows a distance to grow or shrink:
Play around with that and you should be able to get what you want.
回答3:
Yes, it is definitely possible to do this with Auto Layout. Through a series of steps, that I think might be too long to post as an answer, you can retain the spacing between your ImageViews and keep the alignment of the text the same.
Essentially, you will have to pin a corner of each ImageView and remove some constraints so that it doesn't automatically compress the spacing when you change the orientation.
Full explanation on how to do this (pretty much exactly what you are asking for) is explained in this tuorial. You can find it about halfway through the page.
Hope this is what you were looking for.
来源：https://stackoverflow.com/questions/18213376/working-with-autolayout-in-portrait-and-landscape