iOS:核心动画之关键帧动画CAKeyframeAnimation

#import "ViewController.h"
@interface ViewController ()
@property (strong,nonatomic)CALayer *subLayer; //声明核心动画子层
@end

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //创建子层
    self.subLayer = [CALayer layer];
    //设置子层大小
    self.subLayer.bounds = CGRectMake(0, 0, 100, 100);
    //设置子层的位置
    self.subLayer.position = CGPointMake(100, 100);
    //设置子层的背景颜色
    self.subLayer.backgroundColor = [[UIColor redColor]CGColor];
    //添加子层到根层
    [self.view.layer addSublayer:self.subLayer];
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    //创建关键帧动画
    CAKeyframeAnimation *keyframe = [[CAKeyframeAnimation alloc]init];
    //设置变化属性值为透明度
    keyframe.keyPath = @"opacity";

    //设置每一帧动画的透明度时刻值
    keyframe.values = @[@1.0,@0.5,@0.0,@0.5,@1.0];
    
    //设置动画持续事件
    keyframe.duration = 1.0f;
    //添加动画到子层
    [self.subLayer addAnimation:keyframe forKey:@"keyAnimation"]; //forkey:的参数可以自己设置，就是一个标示符,区别开其他的动画
}

#import "ViewController.h"
#define MAX_CLICKED_NUM 4    //触摸的最大次数
@interface ViewController ()
@property (strong,nonatomic)NSMutableArray *points;  //用于存放触摸屏幕的次数
@property (strong,nonatomic)CALayer *subLayer;//声明核心动画子层
@end

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //初始化
    self.points = [NSMutableArray array];
    
    //创建子层
    self.subLayer = [CALayer layer];
    self.subLayer.bounds = CGRectMake(0, 0, 100, 100);
    self.subLayer.position = CGPointMake(100, 100);
    self.subLayer.backgroundColor = [[UIColor redColor]CGColor];
    
    //添加子层到根层
    [self.view.layer addSublayer:self.subLayer];
    
}

//触摸事件的处理
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    //获取当前触摸点
    CGPoint location = [[touches anyObject]locationInView:self.view];
    
    //判断当前的点的个数
    if (self.points.count < MAX_CLICKED_NUM)
    {
        //添加当前点
        [self.points addObject:[NSValue valueWithCGPoint:location]];
    }
    else
    {
        
        //创建关键帧动画
        CAKeyframeAnimation *keyanimation = [[CAKeyframeAnimation alloc]init];
        
        //设置该变量为位置position
        keyanimation.keyPath = @"position";
        
        //设置每一帧动画的位置值
        keyanimation.values = self.points;
        
        //设置动画持续时间
        keyanimation.duration = 3.0f;
        
        //设置动画不在恢复原状
        keyanimation.removedOnCompletion = NO;
        keyanimation.fillMode = kCAFillModeForwards;
        
        //设置代理
        keyanimation.delegate = self;
        
        //添加动画到层
        [self.subLayer addAnimation:keyanimation forKey:@"keyanimation"];
    }
    
}

#pragma mark -动画代理方法
-(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
{
    //关闭隐式动画
    [CATransaction begin];
    [CATransaction setDisableActions:YES];
    
    //停留在最后的位置
    self.subLayer.position = [[self.points lastObject]CGPointValue];
    
    //提交动画事物
    [CATransaction commit];
    
    //删除上一次动画结束后保存的所有的数据
    [self.points removeAllObjects];
}

#import "ViewController.h"

@interface ViewController ()
@property (strong,nonatomic)CALayer *subLayer;     //声明核心动画子层用作动画层
@property (assign,nonatomic)CGMutablePathRef path; //声明可变的绘图路径
@property (strong,nonatomic)CALayer *DrawLayer;    //声明核心动画子层用来绘图层
@end

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    
    //创建绘图子层
    self.DrawLayer = [CALayer layer];
    self.DrawLayer.bounds = self.view.bounds;
    self.DrawLayer.position = CGPointMake(0, 0);
    self.DrawLayer.anchorPoint = CGPointMake(0, 0);
    self.DrawLayer.backgroundColor = [[UIColor whiteColor]CGColor];

    //设置绘图子层的代理,它会调用协议中的绘图方法
    self.DrawLayer.delegate = self;
    
    //添加绘图子层
    [self.view.layer addSublayer:self.DrawLayer];
    
    
    
    //创建动画子层
    self.subLayer = [CALayer layer];
    self.subLayer.bounds = CGRectMake(0, 0, 100, 100);
    self.subLayer.position = CGPointMake(100, 100);
    self.subLayer.backgroundColor = [[UIColor redColor]CGColor];

    //添加动画子层
    [self.view.layer addSublayer:self.subLayer];
}

//触摸点击事件的处理
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    //获取当前触摸点
    CGPoint location = [[touches anyObject]locationInView:self.view];
        
    //创建路经
    self.path = CGPathCreateMutable();
    
    //将当前点加到路径中去
    CGPathMoveToPoint(self.path, NULL, location.x, location.y);
    
}

//触摸移动事件的处理
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    //获取当前触摸点
    CGPoint location = [[touches anyObject]locationInView:self.view];
    
    //将当前点加到路径中去
    CGPathAddLineToPoint(self.path, NULL, location.x, location.y);
    
    //让绘图子层绘图
    [self.DrawLayer setNeedsDisplay];
}

//触摸结束事件的处理
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    
    //创建帧动画
    CAKeyframeAnimation *keyAnimation = [[CAKeyframeAnimation alloc]init];
    
    //设置改变属性值为位置position
    keyAnimation.keyPath = @"position";
    
    //设置动画路径为绘制的路径
    keyAnimation.path = self.path;
    
    //设置动画持续时间
    keyAnimation.duration = 3.0f;
    
    
    //设置动画结束时保持不变,不在恢复原状
    keyAnimation.removedOnCompletion = NO;
    keyAnimation.fillMode = kCAFillModeForwards;
    
    
    //设置帧动画代理
    keyAnimation.delegate = self;
    
    
    //添加帧动画到动画子层
    [self.subLayer addAnimation:keyAnimation forKey:@"keyAnimation"];
}

#pragma mark -动画代理方法
-(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
{
    //释放路径
    CGPathRelease(self.path);
}

#pragma mark -UILayer画图方法
-(void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx
{
    //添加路径
    CGContextAddPath(ctx, self.path);
    
    //设置颜色
    CGContextSetStrokeColorWithColor(ctx, [[UIColor blueColor]CGColor]);
    
    //绘路径
    CGContextDrawPath(ctx, kCGPathStroke);
}