UIView 主要负责视图与用户的交互，真正的内容显示是通过UIView里面的图层CALayer来完成的（没有交互能力）

1.创建CALayer

CALayer *layer = [CALayer layer];

layer.backgroundColour = [UIColor redColor].CGColor;---颜色类型必须为CGColor;

layer.frame = CGRectMake(50,50,100,100);//定位layer在父视图的位置

layer.cornerRadius = 50;//设置圆角，定为宽度的一半可以将整个图形变为圆形

layer.borderColor = [UIColor blueColor].CGColor;//增加边框的颜色

layer.borderWidth = 2;//增加的边框的宽度

--layer.position = self.view.center;//layer在父视图的图钉定位,与frame一样

--layer.anchorPoint = CGPointMake(1,1)//在layer内的图钉定位点，范围为0-1.

[self.view.layer addSublayer:layer];

 

2.Layer 动画

旋转

_layer.transform = CATransform3DRotate(_layer.transform,10/180.0*M_PI,1,1,1);

放大缩小

_layer.transform = CATransform3DScale(_layer.transform,2,2,2);按两倍放大

平移

_layer.transform = CATransform3DTranslate(_layer.transform,10,10,0);

//基本动画

渐变，从有到无

CABasicAnimation *capacityAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];

capacityAnimation.fromValue = @1;

capacityAnimation.fromValue = @0;

[_layer addAnimation:capacityAnimation forKey:nil];

放大，从0.5倍到2倍

CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];

scaleAnimation.fromValue = @0.5;

scaleAnimation.fromValue = @2;

scaleAnimation.fillMode = kCAFillModeForwards;最后以什么填充

scaleAnimation.repeatCount = MAXFLOAT;重复次数

scaleAnimation.duration = 1;持续时间

[_layer addAnimation:scaleAnimation forKey:nil];

位置移动

CABasicAnimation *moveAnimation = [CABasicAnimation animationWithKeyPath:@"position"];

moveAnimation.toValue = [NSValue valueWithCGPoint:CGPointMake(200, 200)];

[_layer addAnimation:moveAnimation forKey:nil];

旋转

CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:@"transform"];

rotateAnimation.fromValue = [NSValue valueWithCATransform3D:CATransform3DIdentity];

rotateAnimation.toValue = [NSValue valueWithCATransform3D:CATransform3DRotate(_layer.transform,M_PI,0,0,1)];

[_layer addAnimation:rotateAnimation forKey:nil];

多种动画效果叠加

CAAnimationGroup *group = [CAAnimationGroup animation];

    group.duration = 1;

    group.removedOnCompletion = NO;

    group.fillMode = kCAFillModeForwards;

    group.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];

    group.animations = @[capacityAnimation, scaleAnimation, moveAnimation, rotateANimation];

    [_layer addAnimation:group forKey:nil];

在旋转中，上边的写法转换成弧度之后不能转多圈，下面实现转多圈

    CABasicAnimation *zrotateANimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];

    zrotateANimation.fromValue = [NSNumber numberWithFloat:0];

    zrotateANimation.toValue = [NSNumber numberWithFloat:M_PI * 4.0];//4圈

 

：

https://zsisme.gitbooks.io/ios-/content/chapter1/layers-and-trees.html