利用 CALayer 可以实现复杂的动画效果，同时 CALayer 在运动过程中，需要点击 CALayer，同时能够监控到点击的对象。下面是实现的效果和过程。
实现过程：
#import "AnimView.h"
@implementation AnimView
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
[self setBackgroundColor:[UIColor clearColor]];
UITapGestureRecognizer *tapGesture=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(touchesPoint:)];
[self addGestureRecognizer:tapGesture];
[tapGesture release];
}
return self;
}
-(void) drawRect:(CGRect)rect
{
[NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(stratAnim:) userInfo:nil repeats: NO];
}
-(void)stratAnim:(id)sender
{
//添加层
layer2 = [CALayer layer];
[layer2 setBackgroundColor:[[UIColor redColor] CGColor]];
layer2.bounds = CGRectMake(0, 0, 60,40);//层设置为图片大小
layer2.position = CGPointMake(25,25);//层在view的位置
[self.layer addSublayer:layer2];//将层加到当前View的默认layer下
[self startFlyStarAnimation];
}
-(void) startFlyStarAnimation
{
//运动轨迹
CGMutablePathRef thePath=CGPathCreateMutable();
CGPathMoveToPoint(thePath,NULL,self.center.x,self.center.y);
CGPathAddLineToPoint(thePath, NULL, self.center.x, self.center.y-45);
CGPathAddLineToPoint(thePath, NULL, self.center.x, self.center.y+45);
CGPathAddLineToPoint(thePath, NULL, self.center.x, self.center.y);
//添加动画
CAKeyframeAnimation * animation;
animation=[CAKeyframeAnimation animationWithKeyPath:@"position"];
animation.path=thePath;
animation.duration=3.0;
animation.repeatCount=2;
CFRelease(thePath);
[animation setDelegate:self];
//[self animationDidStop:animation finished:YES];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]];
[layer2 addAnimation:animation forKey:kCATransition];
}
//动画停止
-(void) animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
{
NSLog(@">>>>动画停止了");
}
//touch事件
-(void)touchesPoint:(UITapGestureRecognizer *)gestureRecognizer
{
CGPoint locationInView = [gestureRecognizer locationInView:self];
//presentationLayer layer的动画层
CALayer *layer1=[[layer2 presentationLayer] hitTest:locationInView];
if (layer1!=nil) {
NSLog(@"点击了运动的layer");
}
}
- (void)dealloc {
[super dealloc];
}
@end
其中 presentationLayer 是 CALayer 动画的位置层。源代码下载：http://easymorse-iphone.googlecode.com/svn/trunk/iphone.presentlayer/