iOS change auto layout constraints when device rotates

Question

I want to modify the layout constraints when the device rotates. My UIViewController is composed of 2 UIViews, in landscape they are horizontally a

Answer 1

override -(void) viewWillLayoutSubviews in your UIViewController to update your constraints as below code:

-(void) viewWillLayoutSubviews {
     switch(self.interfaceorientation)
     {
          case UIInterfaceOrientationLandscapeLeft:

              break;
          case UIInterfaceOrientationLandscapeRight:

              break;

          case UIDeviceOrientationPortrait:

              break;

          case UIDeviceOrientationPortraitUpsideDown:

              break;

     }
}