如何更新UIImageView的contentMode？

Question

在最初的UIImageView我已将其设置为

mCurrentImageView.contentMode = UIViewContentModeLeft;

因此，如果设备旋转，我将更改contentMode 但它没有效果。我该如何解决？

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

Answer 1

[UIDevice orientation]不会返回这些标识符以进行定位。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消息的视图控制器代码中执行某些操作：

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