在排列和拖动视图知道如何通过手势捕获视图&＃xff0c;在如何通过手势选择到子视图知道如何捕获视图的子视图。现在有个问题&＃xff0c;如何通过手势捕获视图内部的层&＃xff08;Layer&＃xff09;&＃xff0c;如果能&＃xff0c;怎么捕获。
捕获到Layer是很重要的&＃xff0c;这样才能针对具体的Layer做操作&＃xff0c;比如拖动&＃xff0c;比如反转等。
答案是肯定的&＃xff0c;下面写个例子说明一下。
示例中的图&＃xff0c;是在视图默认Layer下的子Layer。当touch&＃xff08;手指拖动&＃xff09;该Layer以外的部分&＃xff0c;则只打印pan …&＃xff0c;当在该Layer上拖动时&＃xff0c;除了打印pan..以外&＃xff0c;还会打印catch it!
这里需要用到CALayer的hitTest方法。
控制器代码很简单。
头文件&＃xff1a;
&＃64;interface TestGestureViewController : UIViewController{
AnimationView *animationView;
实现文件中&＃xff1a;
- (void)viewDidLoad {
[super viewDidLoad];
animationView&＃61;[[AnimationView alloc] initWithFrame:CGRectMake(0, 0, 768, 1024)];
animationView.backgroundColor&＃61;[UIColor blueColor];
[self.view addSubview:animationView];
视图部分&＃xff0c;头文件&＃xff1a;
#import
#import
#define RADIAS 180
&＃64;interface AnimationView : UIView
CALayer *startLayer;
}
- (void) initLayers;
- (void)panPiece:(UIPanGestureRecognizer *)gestureRecognizer;
&＃64;end
实现文件&＃xff1a;
- (id)initWithFrame:(CGRect)frame {
self &＃61; [super initWithFrame:frame];
if (self) {
[self initLayers];
UIPanGestureRecognizer *panGesture &＃61; [[UIPanGestureRecognizer alloc] initWithTarget:self action:&＃64;selector(panPiece:)];
[panGesture setMaximumNumberOfTouches:2];
[self addGestureRecognizer:panGesture];
[panGesture release];
}
return self;
}
- (void) initLayers{
startLayer&＃61;[CALayer layer];
UIImage *image&＃61;[UIImage imageNamed:&＃64;"4.png"];
startLayer.bounds&＃61;CGRectMake(0, 0, image.size.width, image.size.height);
startLayer.contents&＃61;(id)[image CGImage];
startLayer.position&＃61;CGPointMake(768/2-RADIAS, 1024/2);
[self.layer addSublayer:startLayer];
[image release];
}
- (void)panPiece:(UIPanGestureRecognizer *)gestureRecognizer{
NSLog(&＃64;"pan …");
CALayer *layer&＃61;[self.layer hitTest:[gestureRecognizer locationInView:self]];
if (layer&＃61;&＃61;startLayer) {
NSLog(&＃64;"catch it!");
}
}
其中&＃xff0c;捕获Layer的代码&＃xff1a;
CALayer *layer&＃61;[self.layer hitTest:[gestureRecognizer locationInView:self]];
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