IOS动画（3）关键帧动画

浏览数：35 / 时间：2015年06月11日

关键帧动画中的时间系统，模型树和呈现树与基础动画一致，这里主要介绍关键帧动画的用法

CAKeyframeAnimation

- (void)viewDidLoad
{
    [super viewDidLoad];

    CALayer *layer = [CALayer layer];
    layer.bounds = CGRectMake(0, 0, 120, 120);
    layer.position = CGPointMake(100, 300);
    layer.cornerRadius = 60;
    layer.masksToBounds = YES;
    layer.contents = (id)[UIImage imageNamed:@"5.png"].CGImage;
    [self.view.layer addSublayer:layer];

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    CALayer *layer = [self.view.layer.sublayers lastObject];
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"position"];

    //设置关键帧
    //与基础动画不同，关键帧动画必须指明动画初始值
    NSValue *value1 = [NSValue valueWithCGPoint:layer.position];
    NSValue *value2 = [NSValue valueWithCGPoint:CGPointMake(50, 300)];
    NSValue *value3 = [NSValue valueWithCGPoint:CGPointMake(50, 100)];    
    
    animation.duration = 2;
    animation.values = @[value1,value2,value3];
    animation.autoreverses = YES;
    
    [layer addAnimation:animation forKey:nil];
}

这是关键帧动画的第一种写法，就是设定几个关键节点，然后CoreAnimation自动补齐关键节点中的动画

关键帧的另一种写法是设定动画的path，然后layer可以绕着画好的path移动，这种方式可以方便的实现曲线运动的动画效果

- (void)viewDidLoad
{
    [super viewDidLoad];

    CALayer *layer = [CALayer layer];
    layer.bounds = CGRectMake(0, 0, 120, 120);
    layer.position = CGPointMake(100, 300);
    layer.cornerRadius = 60;
    layer.masksToBounds = YES;
    layer.contents = (id)[UIImage imageNamed:@"5.png"].CGImage;
    [self.view.layer addSublayer:layer];
}



- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {    
    CALayer *layer = [self.view.layer.sublayers lastObject];
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    
    //设置关键帧
    //与基础动画不同，关键帧动画必须指明动画初始值
    CGPathRef path = CGPathCreateMutable();
    
    CGPathMoveToPoint(path, NULL, layer.position.x, layer.position.y);//移动到起始点
    CGPathAddCurveToPoint(path, NULL, 160, 280, -30, 300, 55, 400);//绘制二次贝塞尔曲线
    
    CGPathRelease(path);
    
    animation.path = path;
    

    animation.duration = 2;
    animation.autoreverses = YES;
    
    [layer addAnimation:animation forKey:nil];
}

UIView封装关键帧动画

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 20, 120, 120)];
    imageView.image = [UIImage imageNamed:@"5.png"];
    [self.view addSubview:imageView];
}



- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    UIImageView *image = [self.view.subviews lastObject];
    [UIView animateKeyframesWithDuration:5 delay:0 options:UIViewKeyframeAnimationOptionRepeat|UIViewKeyframeAnimationOptionAutoreverse animations:^{
        //添加关键帧
        //第一个关键帧为开始位置，无需添加
        
        //第二个关键帧:从0秒开始持续50%的时间，也就是5.0*0.5=2.5秒
        [UIView addKeyframeWithRelativeStartTime:0 relativeDuration:0.5 animations:^{
            image.center = CGPointMake(50, 50);
        }];
        
        //第三个关键帧，从0.5*5.0秒开始，持续5.0*0.25=1.25秒
        [UIView addKeyframeWithRelativeStartTime:0.5 relativeDuration:0.25 animations:^{
            image.center = CGPointMake(150, 50);
        }];
        
        //第四个关键帧：从0.75*5.0秒开始，持所需5.0*0.25=1.25秒
        [UIView addKeyframeWithRelativeStartTime:0.75 relativeDuration:0.25 animations:^{
            image.center = CGPointMake(150, 350);
        }];
    } completion:nil];
    
}