橫屏下UIWindow添加多個view自動旋轉的解決方案

在橫屏應用中，使用keyWindow添加一個視圖，切換設備橫屏方向，發現添加的視圖不會隨着變化方向。

並且只有Window的RootViewController可以監聽到屏幕旋轉變化。

[[UIApplicationsharedApplication].keyWindow addSubview:view];

解決方法如下：

定義RotateWindow繼承UIWindow，並重寫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];
}

定義RotateViewController作為window的RootViewController，並重寫以下方法

// 僅允許橫屏
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations.
    return (interfaceOrientation == UIInterfaceOrientationLandscapeLeft || interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}

// 設備旋轉時修改添加視圖方向
- (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++;
    }
}