iOS：核心动画之基本动画CABasicAnimation

    //创建子层
    self.subLayer = [CALayer layer];
    
    self.subLayer.bounds = CGRectMake(0, 0, 100, 100);
    
    self.subLayer.position = CGPointMake(100, 100);
    
    self.subLayer.backgroundColor = [[UIColor redColor]CGColor];
    
    self.subLayer.cornerRadius = 50;
    
    [self.view.layer addSublayer:self.subLayer];

    //创建tap手势
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(Tap:)];
    tap.numberOfTapsRequired = 1;
    tap.numberOfTouchesRequired = 1;
    [self.view addGestureRecognizer:tap];

#pragma mark -tap手势处理
-(void)Tap:(UITapGestureRecognizer *)sender
{
    //获取当前的点击的位置
    CGPoint location = [sender locationInView:self.view];
    
    //创建基本动画
    CABasicAnimation *basicAnimation = [[CABasicAnimation alloc]init];
    
    basicAnimation.duration = 5.0f;
    
    //设置动画改变的值为position
    basicAnimation.keyPath = @"position";
    
    //BasicAnimation.fromValue用当前位置，不用设置
    basicAnimation.toValue = [NSValue valueWithCGPoint:location];
    
    
    //动画执行完,停留下来,不返回原值,需要设置下面的两个属性
    basicAnimation.removedOnCompletion = NO;
    basicAnimation.fillMode = kCAFillModeForwards;
    
    //设置代理
    basicAnimation.delegate = self;
    
    
    //设置一个键区分动画,将指定的动画添加到子层中
    [self.subLayer addAnimation:basicAnimation forKey:@"BasicAnimation"];
    
    
    //没有具体实现代理方法的情况下,subLayer虽然发生移动,但是它的真正位置并没有发生改变
    //NSLog(@"%@",NSStringFromCGPoint(self.subLayer.position));
}

- (IBAction)buttonClicked:(UIButton *)sender
{
    if (sender.tag == 0)
    {
        //动画暂停
        [self animationPause];
        sender.tag = 1;
    }
    else
    {
        //动画恢复
        [self animationResume];
        sender.tag = 0;
    }
}

//动画暂停
-(void)animationPause
{
    //获取当前暂停时间
    //CFTimeInterval pauseTime = [self.subLayer convertTime:CACurrentMediaTime() fromLayer:nil];
    CFTimeInterval pauseTime = CACurrentMediaTime();
    
    //层的速度为0,停止动画
    self.subLayer.speed = 0;
    
    //保存暂停时间,便于恢复
    self.subLayer.timeOffset = pauseTime;
}

//动画恢复
-(void)animationResume
{
    //获取暂停时保存的时间
    CFTimeInterval pauseTime = self.subLayer.timeOffset;
    self.subLayer.timeOffset = 0;
    
    
    //设置速度
    self.subLayer.speed = 1.0;
    
    //清除开始时间
    self.subLayer.beginTime = 0.0;
    
    
    //计算开始时间
    CFTimeInterval beginTime = [self.subLayer convertTime:CACurrentMediaTime() fromLayer:nil] - pauseTime;
    
    //重设开始时间
    self.subLayer.beginTime = beginTime;
}

#pragma mark -动画代理的方法
//动画开始时触发的方法
-(void)animationDidStart:(CAAnimation *)anim
{
    //开始时的当前值
    //NSLog(@"animationDisStart:%@",((CABasicAnimation *)anim).fromValue);
}

//动画停止时触发的方法
-(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
{
    //停止时的终点值
    //NSLog(@"animationDidStop,%@",((CABasicAnimation*)anim).toValue);
    
    //将subLayer的属性值真正变为动画停止时的属性值
    NSValue *toValue = ((CABasicAnimation*)anim).toValue;
    CGPoint point = [toValue CGPointValue];
    self.subLayer.position = point;
}
@end