横屏下UIWindow添加多个view自动旋转的解决方案

在横屏应用中，使用keyWindow添加一个视图，切换设备横屏方向，发现添加的视图不会随着变化方向。

并且只有Window的RootViewController可以监听到屏幕旋转变化。

[[UIApplicationsharedApplication].keyWindow addSubview:view];

解决方法如下：

定义RotateWindow继承UIWindow，并重写addSubview方法。AppDelegate中的window使用RotateWindow。

#define degreesToRadian(x) (M_PI * (x) / 180.0)

- (void)addSubview:(UIView *)view {
    if ([self.subviews count] >= 1) {
        float angle = ([UIDevice currentDevice].orientation == UIDeviceOrientationLandscapeLeft)?90:-90;
        view.transform = CGAffineTransformMakeRotation(degreesToRadian(angle));
        view.frame = CGRectOffset(self.frame, 0, 0);
    }

    [super addSubview:view];
}

定义RotateViewController作为window的RootViewController，并重写以下方法

// 仅允许横屏
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations.
    return (interfaceOrientation == UIInterfaceOrientationLandscapeLeft || interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}

// 设备旋转时修改添加视图方向
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
    UIWindow *window = [UIApplication sharedApplication].keyWindow;
    int i = 0;
    for (UIView *view in window.subviews) {
        if (i != 0) {
            CGAffineTransform transform = view.transform;
            transform = CGAffineTransformRotate(transform,  degreesToRadian(180));
            view.transform = transform;
        }
        i++;
    }
}