Core Animation

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [touches anyObject];
    
    CGPoint point = [touch locationInView:self.view];
    [self moveToPoint:point];
    
}

-(void)moveToPoint:(CGPoint)point{
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"] ;
    // 1.设置目的点
    animation.toValue =[NSValue valueWithCGPoint:point];
    // 2.设置动画时长
    animation.duration =0.5;
    // 3.设置完成后删除动画
    animation.removedOnCompletion = NO;
    // 4.设置模式为向前填充
    animation.fillMode = kCAFillModeBoth;
    // 5.设置速度模式为先慢后快
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
    // 6.设置开始时长延后1秒
    animation.beginTime  =CACurrentMediaTime() + 1;
    // 7.将动画添加到Layer上开始执行
    [_redview.layer addAnimation:animation forKey:nil];

}

#pragma mark 暂停动画
- (void)pause
{
    // 记录停止瞬间的时间偏移量，取出当前动画定格对应的事件
    CFTimeInterval time = [_redView.layer convertTime:CACurrentMediaTime() fromLayer:nil];
    // 利用图层的timeOffset记录暂停的时间偏移量
    _redView.layer.timeOffset = time;
    
    NSLog(@"%f", time);
    
    // 将速度设置为0，可以停止动画
    _redView.layer.speed = 0.0;
}

#pragma mark 继续动画
- (void)resume
{
    // 恢复时间量
    CFTimeInterval pauseTime = _redView.layer.timeOffset;
    // 取当前媒体时间
    CFTimeInterval time = CACurrentMediaTime();
    // 计算时间差值
    CFTimeInterval offset = time - pauseTime;
    NSLog(@"%f", offset);
   
    // 设置图层动画的起始时间
    _redView.layer.beginTime = offset;
    _redView.layer.timeOffset = 0;
    
    // 恢复速度为1
    _redView.layer.speed = 1.0;
}

// 用户抬起手指，才会执行，通常会针对touchesMove中的处理，做一些收尾工作
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    
}

#pragma mark - 动画代理方法
- (void)animationDidStart:(CAAnimation *)anim
{
    NSLog(@"动画开始 %@", NSStringFromCGPoint(_redView.center));
}

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
{
    CABasicAnimation *animation = (CABasicAnimation *)anim;
    
    // 动画结束后，修正视图的位置
    CGPoint point = [animation.toValue CGPointValue];
    _redView.center = point;

    NSLog(@"动画结束 %@ %@", NSStringFromCGPoint(_redView.center), animation.toValue);
}

#pragma mark - 动画方法
#pragma mark 旋转动画
- (void)rotation
{
    
    CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
    
    _redView.layer.anchorPoint = CGPointMake(1, 1);
    
    // 设置旋转角度，转360
    anim.toValue = @(2 * M_PI);
    // 要无限循环转动，指定一个非常大的数值
    // 对于无限循环的动画，需要处理动画累加的问题
    anim.repeatCount = HUGE_VALF;
//    anim.repeatCount = MAXFLOAT;
    
    // 如果要退出到后台，再次回复的时候继续执行动画，需要设置removedOnCompletion = NO
    anim.removedOnCompletion = NO;
    
    anim.duration = 1.0f;
    
    [_redView.layer addAnimation:anim forKey:@"myRotation"];
}

#pragma mark 缩放动画
- (void)scale
{
    // 1. 实例化
    CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
    
    // 2. toValue
    anim.toValue = @(2.0);
    anim.repeatCount = 3;
    // 自动反向执行动画
    anim.autoreverses = YES;
    
    anim.duration = 0.3f;
    
    [_redView.layer addAnimation:anim forKey:nil];
}