1
我有一个CALayer
它有一个CAKeyFrameAnimation
。iOS - 检测CALayer内容的变化
有没有办法检测到CALayer
的内容变化?
这就像,每当CALayer
的内容(图像)由于CAKeyFrameAnimation
而改变时,我想播放一个短的声音与AVAudioPlayer
。
UPDATE
我做这样的解决它。
- (void) viewDidLoad
{
// init CADisplayLink to catch the changing moment
CADisplayLink *displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(checkContents:)];
[displayLink setFrameInterval:6] // checking by every 0.1 sec (6 frames)
[displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
- (void) checkContents:(CADisplayLink *) sender;
{
// _newImage and _oldImage are class variables. (UIImage)
// animatingView is a `UIImageView` where its layer's contents is being changed by `CAKeyFrameAnimation`
CALayer *presentLayer = [animatingView.layer presentationLayer];
_newImage = presentLayer.contents;
if (![_newimage isEqual:_oldImage])
{
NSLog(@"Image changed! From %@ to %@", _oldImage, _newImage);
}
_oldImage = _newImage;
}
当然,不要忘记在不再需要时使CADisplayLink
无效。
谢谢你快回答!我会给它一个! – Woonohyo