多个CALayer的联动

在如何通过手势捕获CALayer基础上做了个示例，两个CALayer的联动，当拖动左侧的Layer的时候，右侧的Layer随动。因为右侧的动画没有关闭，有延迟，产生随动的效果。如果不想延迟，可参考拖动动画的问题及解决。

在视图的头文件：

#import <UIKit/UIKit.h> 
#import <QuartzCore/QuartzCore.h>

#define RADIAS 180

@interface AnimationView : UIView <UIGestureRecognizerDelegate>{ 
    CALayer *startLayer; 
    CALayer *startLayer2; 
}

- (void) initLayers;

- (void)panPiece:(UIPanGestureRecognizer *)gestureRecognizer;

@end

实现文件：

#import "AnimationView.h"

@implementation AnimationView

- (id)initWithFrame:(CGRect)frame { 
    
    self = [super initWithFrame:frame]; 
    if (self) { 
        [self initLayers]; 
        
        UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panPiece:)]; 
        [panGesture setMaximumNumberOfTouches:2]; 
        [self addGestureRecognizer:panGesture]; 
        [panGesture release]; 
    } 
    return self; 
}

- (void) initLayers{ 
    startLayer=[CALayer layer]; 
    UIImage *image=[UIImage imageNamed:@"4.png"]; 
    startLayer.bounds=CGRectMake(0, 0, image.size.width, image.size.height); 
    startLayer.contents=(id)[image CGImage]; 
    startLayer.position=CGPointMake(768/2-RADIAS, 1024/2); 
    
    [self.layer addSublayer:startLayer]; 
    
    [image release]; 
    
    startLayer2=[CALayer layer]; 
    image=[UIImage imageNamed:@"5.png"]; 
    startLayer2.bounds=CGRectMake(0, 0, image.size.width, image.size.height); 
    startLayer2.contents=(id)[image CGImage]; 
    startLayer2.position=CGPointMake(768/2+RADIAS, 1024/2); 
    
    [self.layer addSublayer:startLayer2]; 
    
    [image release]; 
}

- (void)panPiece:(UIPanGestureRecognizer *)gestureRecognizer{ 
    NSLog(@"pan …"); 
    CGPoint locationInView = [gestureRecognizer locationInView:self]; 
    CALayer *layer=[self.layer hitTest:locationInView]; 
    
    if (layer==startLayer) { 
        NSLog(@"catch it!"); 
        [CATransaction begin]; 
        
        CGPoint newLocation=locationInView; 
        newLocation.x+=RADIAS*2; 
        startLayer2.position=newLocation; 
        
        [CATransaction begin]; 
        [CATransaction setValue:[NSNumber numberWithBool:YES] 
                         forKey:kCATransactionDisableActions]; 
        startLayer.position=locationInView; 
        [CATransaction commit]; 
        [CATransaction commit]; 
    } 
}