代码片段 分段动画

    CAKeyframeAnimation *animation1 = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    animation1.duration = 1.6;
    animation1.repeatCount = CGFLOAT_MAX;
    animation1.calculationMode = kCAAnimationLinear;
    animation1.values = @[[NSValue valueWithCGPoint:CGPointMake(center.x + 40, center.y)],
                         [NSValue valueWithCGPoint:CGPointMake(center.x + 100, center.y)],
                         [NSValue valueWithCGPoint:CGPointMake(center.x + 100, center.y)],
                         [NSValue valueWithCGPoint:CGPointMake(center.x, center.y)]];
    animation1.keyTimes = @[@(0),@(0.4),@(1),@(1)];
    
    CAKeyframeAnimation *animation2 = [CAKeyframeAnimation animationWithKeyPath:@"opacity"];
    animation2.duration = 1.6;
    animation2.repeatCount = CGFLOAT_MAX;
    animation2.calculationMode = kCAAnimationLinear;
    animation2.values = @[@1, @0, @0];
    animation2.keyTimes = @[@0, @0.7, @1];
    
    [self.extraView1.layer addAnimation:animation1 forKey:@"extraView1_animation1"];
    [self.extraView2.layer addAnimation:animation1 forKey:@"extraView2_animation1"];
    [self.extraView1.layer addAnimation:animation2 forKey:@"extraView1_animation2"];
    [self.extraView2.layer addAnimation:animation2 forKey:@"extraView2_animation2"];