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我有一个 CAKeyframeAnimation 调用 animationDidStart: 和 animationDidStop:finished:，正如预期的那样，当动画被允许运行时。

当我在中断期间暂停动画（通话、按下 home btn 等）时，animationDidStop:finished: 会触发 NO 标志，正如预期的那样。

但是，重新启动暂停的动画后，animationDidStart: 和 animationDidStop:finished: 永远不会再次触发。动画确实在视觉上继续并完成，但我没有收到该事件。我需要知道动画何时停止，以便重新开始我的游戏循环。

我按照这个暂停/重新启动动画。

请告诉我我做错了什么。谢谢！

- (void)takeFlight
{   
    CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    pathAnimation.calculationMode = kCAAnimationPaced;
    pathAnimation.removedOnCompletion = NO;
    pathAnimation.duration = FLY_ANIM_TIME;
    pathAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
    pathAnimation.delegate = self;

    CGPoint endPoint = CGPointMake(self.view.frame.size.width/2, self.view.frame.size.height/3);
    CGMutablePathRef curvedPath = CGPathCreateMutable();
    CGPathMoveToPoint(curvedPath, NULL, xPos, yPos);
    CGPathAddQuadCurveToPoint(curvedPath, NULL, -100.0, -50.0, 200.0, 100.0);
    pathAnimation.path = curvedPath;
    CGPathRelease(curvedPath);

    [shipView.layer addAnimation:pathAnimation forKey:@"flyin"];
    shipView.center = endPoint; 
}

-(void)pauseFlight
{
    CALayer *layer = (CALayer *)shipView.layer;
    CFTimeInterval pausedTime = [layer convertTime:CACurrentMediaTime() fromLayer:nil];
    layer.speed = 0.0;
    layer.timeOffset = pausedTime;
}

-(void)resumeFlight
{   
    CALayer *layer = (CALayer *)shipView.layer;
    CFTimeInterval pausedTime = [layer timeOffset];
    layer.speed = 1.0;
    layer.timeOffset = 0.0;
    layer.beginTime = 0.0;
    CFTimeInterval timeSincePause = [layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
    layer.beginTime = timeSincePause;
}

- (void)animationDidStart:(CAAnimation *)animation
{
    NSLog(@"anim did start");
}

- (void)animationDidStop:(CAAnimation *)animation finished:(BOOL)flag
{   
    NSLog(@"anim did stop, flag is: %d", flag);

}
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