ios - 如何在应用模糊的情况下交叉淡化 UIImageView 的图像

Question

我正在尝试交叉淡入淡出到新图像。这是一个添加了 UIVisualEffectView 的 UIImageView：

self.bgBlurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
self.visualEffectView = [[UIVisualEffectView alloc] initWithEffect:self.bgBlurEffect];

self.visualEffectView.frame = self.bgImageView.bounds;
[self.bgImageView addSubview:self.visualEffectView];

这是我尝试淡入新图像的方式：

UIImage *toImage = [UIImage imageNamed:imgName];

CABasicAnimation *crossFade = [CABasicAnimation animationWithKeyPath:@"contents"];
crossFade.duration = 2.5;
crossFade.delegate = self;
crossFade.fromValue = (id)self.bgImageView.image.CGImage;
crossFade.toValue = (id)toImage.CGImage;
[self.bgImageView.layer addAnimation:crossFade forKey:@"animateContents"];
self.bgImageView.image = toImage;

这实际上在模拟器中有效，但在设备（iPhone 6）上，图像完全变灰 2.5 秒，然后新图像立即出现。有想法该怎么解决这个吗？

编辑：这也不起作用：

[UIView transitionWithView:self.bgImageView
                  duration:2.5
                   options:UIViewAnimationOptionTransitionCrossDissolve
                animations:^{
                    self.bgImageView.image = toImage;
                } completion:nil];

Answer 1

也许这种方法适用于淡入淡出动画：

self.bgImageView.image = toImage;

CATransition *fadeTransition = [CATransition animation];
fadeTransition.duration = 2.5;
fadeTransition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
fadeTransition.type = kCATransitionFade;

[self.bgImageView.layer addAnimation:fadeTransition forKey:nil];