我正在努力采用多任务来支持应用程序的拆分视图.但我发现app在右边时没有调用traitCollectionDidChange.有没有人对此有所了解?
解决方法
 你试过viewWillTransitionToSize方法吗?这用于通知容器其视图的大小即将更改. 
  
 
        Objective-C的
- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
迅速
func viewWillTransitionToSize(size: CGSize,withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
    coordinator.animatealongsideTransition(nil,completion: {
    if UIDevice.currentDevice().orientation.isLandscape.boolValue {
        print("landscape")
    } else {
        print("portrait")
    }
}