iOS 动画篇 （二） CAShapeLayer与CoreAnimation结合使用

　　接上一篇博客 iOS 动画篇（一） Core Animation

　　CAShapeLayer是CALayer的一个子类，使用这个类能够很轻易实现曲线的动画。

　　先来一个折线动画效果：

　　

示例代码：

//1.生成path
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:CGPointMake(, )];
    [path addLineToPoint:CGPointMake(, )];
    [path addLineToPoint:CGPointMake(, )];
    [path addLineToPoint:CGPointMake(, )];
    [path addLineToPoint:CGPointMake(, )];
    [path addLineToPoint:CGPointMake(, )];

    self.shapeLayer.path = path.CGPath;

    //设置animation
    CABasicAnimation *strokeAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    strokeAnimation.fromValue = @;
    strokeAnimation.toValue = @;
    strokeAnimation.duration = .f;

    CABasicAnimation *lineWidthAnimation = [CABasicAnimation animationWithKeyPath:@"lineWidth"];
    lineWidthAnimation.fromValue = @;
    lineWidthAnimation.toValue = @;
    lineWidthAnimation.duration = .f;

    CABasicAnimation *strokeColorAnimation = [CABasicAnimation animationWithKeyPath:@"strokeColor"];
    strokeColorAnimation.fromValue = (id)([UIColor redColor].CGColor);
    strokeColorAnimation.toValue = (id)([UIColor magentaColor].CGColor);
    strokeColorAnimation.duration = .f;

    CAAnimationGroup *group = [CAAnimationGroup animation];
    group.animations = @[strokeAnimation, lineWidthAnimation, strokeColorAnimation];
    group.duration = .f;
    group.fillMode = kCAFillModeForwards;
    group.removedOnCompletion = NO;
    [self.shapeLayer addAnimation:group forKey:@"groupAnimation"];

　　现在介绍CAShapeLayer，CAShapeLayer几乎所有的属性都可以用来做动画，比如说path、strokeEnd、strokeStart、lineWidth等等，利用这些属性可以实现多种曲线动画。

　　接下来，介绍一个CAShapeLayer与贝塞尔曲线结合的曲线动画，效果图：

　　

代码：

//二次贝塞尔曲线
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:CGPointMake(, self.shapeLayer.bounds.size.height / )];
    [path addCurveToPoint:CGPointMake(self.shapeLayer.bounds.size.width, ) controlPoint1:CGPointMake(, ) controlPoint2:CGPointMake(, )];
    self.shapeLayer.path = path.CGPath;

    //绘制动画
    CABasicAnimation *strokeEndAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    strokeEndAnimation.fromValue = @0.5;
    strokeEndAnimation.toValue = @;
    strokeEndAnimation.duration = .f;

    [self.shapeLayer addAnimation:strokeEndAnimation forKey:@"strokeAnimation"];

    CABasicAnimation *strokeStartAnimation = [CABasicAnimation animationWithKeyPath:@"strokeStart"];
    strokeStartAnimation.fromValue = @0.5;
    strokeStartAnimation.toValue = @;
    strokeStartAnimation.duration = .f;

    [self.shapeLayer addAnimation:strokeStartAnimation forKey:@"strokeStartAnimation"];

　　再来一个看着酷一点的loading动画，效果：

　

代码如下：

self.shapeLayer.backgroundColor = [UIColor clearColor].CGColor;
    self.shapeLayer.strokeColor = [UIColor redColor].CGColor;
    self.shapeLayer.fillColor = [UIColor clearColor].CGColor;
    self.shapeLayer.lineWidth = .f;
    UIBezierPath *storkePath = [UIBezierPath bezierPathWithOvalInRect:self.shapeLayer.bounds];
    self.shapeLayer.path = storkePath.CGPath;
    self.shapeLayer.strokeStart = ;
    self.shapeLayer.strokeEnd = 0.1;

    //旋转动画
    CABasicAnimation *rotateAnimaiton = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotateAnimaiton.duration = .f;
    rotateAnimaiton.repeatCount = CGFLOAT_MAX;
    rotateAnimaiton.removedOnCompletion = NO;
    rotateAnimaiton.fillMode = kCAFillModeForwards;
    rotateAnimaiton.toValue = @(M_PI * );

    //stroke动画
    CABasicAnimation *storkeAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    storkeAnimation.duration = .f;
    storkeAnimation.repeatCount = CGFLOAT_MAX;
    storkeAnimation.fillMode =  kCAFillModeForwards;
    storkeAnimation.removedOnCompletion = NO;
    storkeAnimation.toValue = @();

    CAAnimationGroup *animationGroup = [CAAnimationGroup animation];
    animationGroup.duration = .f;
    animationGroup.repeatCount =CGFLOAT_MAX;
    animationGroup.fillMode = kCAFillModeForwards;
    animationGroup.removedOnCompletion = NO;
    animationGroup.animations = @[rotateAnimaiton, storkeAnimation];
    animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];

    [self.shapeLayer addAnimation:animationGroup forKey:@"indicatorAnimation"];

　　现在我们来看一个CAShapeLayer与mask结合的动画

　　

代码：

CAShapeLayer *shapeLayer = [CAShapeLayer layer];
    self.shapeLayer.mask = shapeLayer;

    UIBezierPath *fromPath = [UIBezierPath bezierPathWithRect:CGRectMake(, , , )];
    UIBezierPath *toPath = [UIBezierPath bezierPathWithRect:CGRectMake(, , , )];
    shapeLayer.path = fromPath.CGPath;

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"path"];
    animation.fromValue = (id)fromPath.CGPath;
    animation.toValue = (id)toPath.CGPath;
    animation.duration = .f;
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeForwards;

    [shapeLayer addAnimation:animation forKey:@"animation"];

　　最后再介绍一个登录动画：

　　分析：这个登录动画一共分为三步

　　1. 在button上添加一个shapeLayer，用path属性实现layer的展开动画

　　2. 在展开动画结束后，为button设置一个shapeLayer的mask，利用layer的path和opacity属性实现收起按钮动画

　　3. 添加一个loading动画到view上

详情见代码：

- (void)viewDidLoad {
    [super viewDidLoad];

    NSLog(@"一个复杂一点的登录动画");
    [self.shapeLayer removeFromSuperlayer];

    UIButton *startButton = ({
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];
        btn.backgroundColor = [UIColor purpleColor];
        [btn setTitle:@"start" forState:UIControlStateNormal];
        btn.frame = (CGRect){{, }, {, }};
        btn.center = self.view.center;

        [btn addTarget:self action:@selector(startAction:) forControlEvents:UIControlEventTouchUpInside];
        btn;
    });

    [self.view addSubview:startButton];

    self.startButton = startButton;

}

- (IBAction)startAction:(UIButton *)sender {
    [self addMaskAnimation];
}

- (void)addMaskAnimation
{
    CAShapeLayer *shapeLayer = [CAShapeLayer new];
    shapeLayer.frame = self.startButton.bounds;
    shapeLayer.fillColor = [UIColor whiteColor].CGColor;
    shapeLayer.strokeColor = [UIColor whiteColor].CGColor;
    shapeLayer.opacity = .3f;
    shapeLayer.path = [UIBezierPath bezierPathWithRect:CGRectMake(self.startButton.bounds.size.width / , , , self.startButton.bounds.size.height)].CGPath;//不初始化则无动画效果

    [self.startButton.layer addSublayer:shapeLayer];

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"path"];
    animation.duration = 0.5f;
    animation.toValue = (__bridge id)[UIBezierPath bezierPathWithRect:self.startButton.bounds].CGPath;
    animation.fillMode = kCAFillModeForwards;
    animation.removedOnCompletion = NO;

    [shapeLayer addAnimation:animation forKey:@"shapeAnimation"];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5f * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [self addPackupAnimation];
    });
}

- (void)addPackupAnimation
{
    CAShapeLayer *maskLayer = [CAShapeLayer layer];
    maskLayer.frame = self.startButton.bounds;
    self.startButton.layer.mask = maskLayer;

    //path动画
    CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"path"];
    pathAnimation.duration = 0.3f;
    pathAnimation.removedOnCompletion = NO;
    pathAnimation.toValue = (__bridge id)[UIBezierPath bezierPathWithArcCenter:CGPointMake(self.startButton.bounds.size.width / , self.startButton.bounds.size.height / ) radius: startAngle: endAngle:M_PI *  clockwise:YES].CGPath;
    pathAnimation.fromValue = (__bridge id)[UIBezierPath bezierPathWithArcCenter:CGPointMake(self.startButton.bounds.size.width / , self.startButton.bounds.size.height / ) radius:self.startButton.bounds.size.width /  startAngle: endAngle:M_PI *  clockwise:YES].CGPath;
    pathAnimation.fillMode = kCAFillModeForwards;

    //透明度动画
    CABasicAnimation *opacityAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
    opacityAnimation.duration = 0.3f;
    opacityAnimation.toValue = @();
    opacityAnimation.fromValue = @();
    opacityAnimation.removedOnCompletion = YES;
    opacityAnimation.fillMode = kCAFillModeForwards;

    CAAnimationGroup *group = [CAAnimationGroup new];
    group.animations = @[pathAnimation];
    group.removedOnCompletion = NO;
    group.fillMode = kCAFillModeForwards;
    group.duration = pathAnimation.duration;

    [maskLayer addAnimation:group forKey:@"packupAnimation"];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        self.startButton.hidden = YES;
        [self addLoadingAnimation];

    });
}

- (void)addLoadingAnimation
{
    CAShapeLayer *shapeLayer =  ({
        CAShapeLayer *layer = [CAShapeLayer layer];
        layer.position = self.view.center;
        layer.bounds = CGRectMake(, , , );
        layer.backgroundColor = [UIColor clearColor].CGColor;
        layer.strokeColor = [UIColor redColor].CGColor;
        layer.fillColor = [UIColor clearColor].CGColor;
        layer.lineWidth = .f;
        UIBezierPath *storkePath = [UIBezierPath bezierPathWithOvalInRect:layer.bounds];
        layer.path = storkePath.CGPath;
        layer.strokeStart = ;
        layer.strokeEnd = 0.1;

        layer;
    });

    [self.view.layer addSublayer:shapeLayer];

    //旋转动画
    CABasicAnimation *rotateAnimaiton = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotateAnimaiton.duration = .f;
    rotateAnimaiton.repeatCount = CGFLOAT_MAX;
    rotateAnimaiton.removedOnCompletion = NO;
    rotateAnimaiton.fillMode = kCAFillModeForwards;
    rotateAnimaiton.toValue = @(M_PI * );

    //stroke动画
    CABasicAnimation *storkeAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    storkeAnimation.duration = .f;
    storkeAnimation.repeatCount = CGFLOAT_MAX;
    storkeAnimation.fillMode =  kCAFillModeForwards;
    storkeAnimation.removedOnCompletion = NO;
    storkeAnimation.toValue = @();

    CAAnimationGroup *animationGroup = [CAAnimationGroup animation];
    animationGroup.duration = .f;
    animationGroup.repeatCount =CGFLOAT_MAX;
    animationGroup.fillMode = kCAFillModeForwards;
    animationGroup.removedOnCompletion = NO;
    animationGroup.animations = @[rotateAnimaiton, storkeAnimation];
    animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];

    [shapeLayer addAnimation:animationGroup forKey:@"indicatorAnimation"];
}

　　核心动画就介绍到这，你可以在这里查看demo。

　　个人原创，转载请注明出处 http://www.cnblogs.com/pretty-guy/p/8268745.html

　　下一篇博客打算介绍利用CADisplayLink与CoreGraphics结合实现动画