UI- Layer的使用总结（附动画）
#pargma mark - Layer
1. 设置当前视图的背景颜色
self.view.backgroundColor = [UIColor lightGrayColor];
2. 创建一个视图，并且设置frame
UIView *myView = [[UIView alloc]initWithFrame:CGRectMake(50, 50, 100, 100)];
3. 将创建的视图添加到当前视图
[self.view addSubview:myView];
4. 设置创建视图的背景颜色
myView.backgroundColor = [UIColor blueColor];
5. 设置视图的层属性，每个视图都关联着一个Layer
设置 创建视图图层 的 背景颜色，即为 视图 本身 的 背景颜色 可通过Debug查看
myView.layer.backgroundColor = [UIColor redColor].CGColor;
// myView.backgroundColor = [UIColor yellowColor];
设置图层的边界宽度
myView.layer.borderWidth = 10;
设置图层的边界颜色 ，默认为黑色
myView.layer.borderColor = [UIColor whiteColor].CGColor;
设置拐点的圆角半径， 可以巧妙的利用该方法画圆（将圆角半径设置为视图宽度的一般即可）
myView.layer.cornerRadius = 50;
添加一张图片
myView.layer.contents = (__bridge id _Nullable)([UIImage imageNamed:@"btn_02"].CGImage);
将图片超出圆角半径的内容裁剪掉
myView.clipsToBounds = YES;
//myView.layer.masksToBounds = YES;
6.基础动画: 3种方式 --> 中心点移动/大小变化/旋转
CABasicAnimation *basicAnimation = [CABasicAnimation animation];
动画时间
basicAnimation.duration = 2;
动画重复次数
basicAnimation.repeatCount = 3;
basicAnimation.removedOnCompletion = YES;
//填充模式4中 至今木有弄懂 `backwards', `forwards', `both' and `removed'
// basicAnimation.fillMode = @"backwards";
6.1 中心点移动动画
basicAnimation.fromValue = [NSValue valueWithCGPoint: CGPointMake(50, 50) ];
basicAnimation.byValue = [NSValue valueWithCGPoint:CGPointMake(200, 200)];
basicAnimation.toValue = [NSValue valueWithCGPoint:CGPointMake(300, 300)];
basicAnimation.keyPath = @"position";
6.2 大小变化动画
basicAnimation.toValue = [NSValue valueWithCGRect:CGRectMake(0, 0, 300, 400)];
basicAnimation.keyPath = @"bounds";
6.3 旋转
basicAnimation.toValue = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(M_PI_4 + M_PI_2, 0, 0, 1)];
basicAnimation.keyPath = @"transform";
//注意：设置完动画后要添加动画
[myLayer addAnimation:basicAnimation forKey:nil];
7. 关键帧动画: 两种方式 --> 定义关键点/定义路径
CAKeyframeAnimation *keyFrameAni = [CAKeyframeAnimation animation];
keyFrameAni.duration = 2;
keyFrameAni.repeatCount = 3;
7.1 定义关键点
NSValue *value1 = [NSValue valueWithCGPoint: CGPointMake(50, 50) ];
NSValue *value2 = [NSValue valueWithCGPoint:CGPointMake(100, 200)];
NSValue *value3 = [NSValue valueWithCGPoint:CGPointMake(300, 300)];
keyFrameAni.keyPath = @"position";
keyFrameAni.values = @[value1,value2,value3];
7.2 定义路径
CGMutablePathRef path = CGPathCreateMutable();
//CGPathAddEllipseInRect(path, nil, CGRectMake(50, 50, 300, 400));
CGPathAddArc(path, nil, 100, 100, 50, M_PI_2, M_PI, YES);
keyFrameAni.path = path;
CGPathRelease(path);
keyFrameAni.keyPath = @"position";
[myLayer addAnimation:keyFrameAni forKey:nil];
8. 转换动画 --> 可有立体效果
CATransition *transAnimaiton = [CATransition animation];
transAnimaiton.duration = 3;
transAnimaiton.type = @"cube";
transAnimaiton.subtype = @"fromTop";
[myLayer addAnimation:transAnimaiton forKey:nil];
