//添加动画

CABasicAnimation *monkeyAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];

monkeyAnimation.toValue = [NSNumber numberWithFloat:2.0 *M_PI];

monkeyAnimation.duration = 1.5f;

monkeyAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

monkeyAnimation.cumulative = NO;

monkeyAnimation.removedOnCompletion = NO; //No Remove

monkeyAnimation.repeatCount = FLT_MAX;

[self.backimageView.layer addAnimation:monkeyAnimation forKey:@"AnimatedKey"];

// 加载动画 但不播放动画

self.backimageView.layer.speed = 0.0;

- (void) startAnimation

{

self.backimageView.layer.speed = 1.0;

self.backimageView.layer.beginTime = 0.0;

CFTimeInterval pausedTime = [self.backimageView.layer timeOffset];

CFTimeInterval timeSincePause = [self.backimageView.layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;

self.backimageView.layer.beginTime = timeSincePause;

}

- (void)stopAnimation

{

CFTimeInterval pausedTime = [self.backimageView.layer convertTime:CACurrentMediaTime() fromLayer:nil];

self.backimageView.layer.speed = 0.0;

self.backimageView.layer.timeOffset = pausedTime;

}