蓝色的子视图，在翻转的情况下触发界面大小的调整。

还是使用通知机制，即：

[[NSNotificationCenter defaultCenter] addObserver:self

                                                 selector:@selector(doRotateAction:)

                                                     name:@”UIDeviceOrientationDidChangeNotification”

                                                   object:nil];

不过，这里发现了个问题，当执行通知触发方法的时候，发现总是执行了多次。其中多出来的情况，设备的方向是不对的：

[UIDevice currentDevice].orientation==UIDeviceOrientationUnknown

如上面代码，返回的值是UIDeviceOrientationUnknown，也就是0。只许过滤这种情况即可，下面是比较完整的视图实现代码：

@implementation ContentView

-(id)initWithCoder:(NSCoder *)aDecoder{

    self = [super initWithCoder:aDecoder];

    if (self) {

        [[NSNotificationCenter defaultCenter] addObserver:self

                                                 selector:@selector(doRotateAction:)

                                                     name:@”UIDeviceOrientationDidChangeNotification”

                                                   object:nil];

    }

    return self;

}

-(void) doRotateAction:(NSNotification *) notification{

    if([UIDevice currentDevice].orientation!=UIDeviceOrientationUnknown){

        NSLog(@”do rotate action: %d”,[[notification object] orientation]);

        if([UIDevice currentDevice].orientation==UIDeviceOrientationPortrait||

           [UIDevice currentDevice].orientation==UIDeviceOrientationPortraitUpsideDown){

            self.frame=CGRectMake(self.frame.origin.x, self.frame.origin.y, 200, 200);

        }else{

            self.frame=CGRectMake(self.frame.origin.x, self.frame.origin.y, 600, 500);

        }

    }

}

-(void)dealloc{

    [[NSNotificationCenter defaultCenter] removeObserver:self];

}