如何更新UIImageView的contentMode？

Question

在初始UIImageView中，我将其设置为

mCurrentImageView.contentMode = UIViewContentModeLeft;

因此，如果设备旋转，我将更改contentMode，但它没有任何影响。我怎么才能修复它？

if ([UIDevice currentDevice].orientation == UIInterfaceOrientationLandscapeLeft || [UIDevice currentDevice].orientation == UIInterfaceOrientationLandscapeRight) {
        mCurrentImageView.contentMode = UIViewContentModeScaleAspectFit;
    }

Answer 1

UIDevice orientation不返回方向的那些标识符。从文档中，该消息将返回以下内容：

typedef enum {
   UIDeviceOrientationUnknown,
   UIDeviceOrientationPortrait,
   UIDeviceOrientationPortraitUpsideDown,
   UIDeviceOrientationLandscapeLeft,
   UIDeviceOrientationLandscapeRight,
   UIDeviceOrientationFaceUp,
   UIDeviceOrientationFaceDown
} UIDeviceOrientation;

要更改内容模式，您应该在willRotate消息中的视图控制器代码中执行一些操作：

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
    if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft || toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
        mCurrentImageView.contentMode = UIViewContentModeScaleAspectFit;
    }
}