核心动画——基础动画

//开始选号- (IBAction)startChoose {    //停掉定时器    [self stopRotating];        //核心动画-基础动画    CABasicAnimation *anim = [CABasicAnimation animation];    anim.keyPath = @"transform.rotation";    anim.toValue = @(2 * M_PI * 3);    anim.duration = 1.5;//    anim.repeatCount = 3;        //开始和结尾比较慢，中间快    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];    anim.delegate = self;    [self.centerWheel.layer addAnimation:anim forKey:nil];        //不能被点击    self.userInteractionEnabled = NO;}//动画停止之后执行- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{    self.userInteractionEnabled = YES;        //2秒后执行    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{        //调用开始转动的方法        [self statrRotating];    });    }