核心动画（CAKeyframeAnimation）

Main.storyboard

ViewController.m

//

//  ViewController.m

//  8A02.核心动画 - CAKeyframeAnimation

//

//  Created by huan on 16/2/4.

//  Copyright © 2016年 huanxi. All rights reserved.

//

#import "ViewController.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

//添加一个圆

CGFloat screenW = [UIScreen mainScreen].bounds.size.width;

UIView *circleView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, screenW, screenW)];

circleView.backgroundColor = [UIColor yellowColor];

//设置圆角

circleView.layer.cornerRadius = screenW * 0.5;

[self.view addSubview:circleView];

//把图片移到顶部

[self.view bringSubviewToFront:self.imageView];

}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

//学习帧动画

//创建一个帧动画

CAKeyframeAnimation *animation = [CAKeyframeAnimation animation];

animation.keyPath = @"position";

//设置动画执行路径 指定四个点

NSValue *value1 = [NSValue valueWithCGPoint:CGPointMake(50, 50)];

NSValue *value2 = [NSValue valueWithCGPoint:CGPointMake(250, 50)];

NSValue *value3 = [NSValue valueWithCGPoint:CGPointMake(250, 250)];

NSValue *value4 = [NSValue valueWithCGPoint:CGPointMake(50, 250)];

//数组第一个是"开始状态" 最后一个是“结束状态”

animation.values = @[value1, value2, value3, value4, value1];

//设置时间

animation.duration = 3;

//设置动画节奏

//    kCAMediaTimingFunctionEaseIn 先慢后快

//    kCAMediaTimingFunctionEaseOut 先慢后快

//    kCAMediaTimingFunctionEaseOut 线性匀速

//    kCAMediaTimingFunctionEaseInEaseOut 中间快两边慢

animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

#warning 内部的path的优先级大于values优先级

//设置路径

CGMutablePathRef path = CGPathCreateMutable();

CGFloat screenW = [UIScreen mainScreen].bounds.size.width;

CGPathAddEllipseInRect(path, NULL, CGRectMake(0, 0, screenW, screenW));

animation.path = path;

//c语言的数据类型，如果create/copy/retain 创建要释放

//添加动画

[self.imageView.layer addAnimation:animation forKey:nil];

}

@end

结果